Discards in the World'S Marine Fisheries. An Update

Full text

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Preparation of this document
This study was prepared as part of the FAO Fishery Industries Division’s Regular
Programme 2.3.3. Fisheries Exploitation and Utilization.
The reference materials used in compiling the quantitative data form part of the
discard database and are provided in the Excel spreadsheet on the accompanying CD-
ROM. A bibliography of the citations used in the text, the references used in the discard
database and sources of other information used in the report are also provided.
Distribution
Directors of Fisheries
Fisheries Research and Training Institutes
Non-governmental organizations (NGOs)
FAO Fisheries Field Projects
FAO Representatives
FAO Regional Fisheries Officers
Bilateral and Multilateral Development Agencies

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Abstract
This study provides an update of the quantity of discards in the world’s marine fisheries
based on a fishery-by-fishery approach. The weighted discard rate is estimated at 8
percent (proportion of the catch discarded). Based on this discard rate, in the 1992–2001
period, yearly average discards are estimated to be 7.3 million tonnes. Because of the
different method used in the current estimate, it is not directly comparable with the
previous estimates of 27 million and 20 million tonnes.
Trawl fisheries for shrimp and demersal finfish account for over 50 percent of
total estimated discards while representing approximately 22 percent of total landings
recorded in the study. Tropical shrimp trawl fisheries have the highest discard rate and
account for over 27 percent of total estimated discards. Demersal finfish trawls account
for 36 percent of the estimated global discards. Most purse-seine, handline, jig, trap and
pot fisheries have low discard rates. Small-scale fisheries generally have lower discard
rates than industrial fisheries. The small-scale fisheries account for over 11 percent of the
discard database landings and have a weighted discard rate of 3.7 percent.
Evidence is presented for a substantial reduction in discards in recent years. The
major reasons for this are a reduction in unwanted bycatch and increased utilization
of catches. Bycatch reduction is largely a result of the use of more selective fishing
gears, introduction of bycatch and discard regulations, and improved enforcement of
regulatory measures. Increased retention of bycatch for human or animal food results
from improved processing technologies and expanding market opportunities for lower-
value catch.
A number of policy issues are discussed. These include a “no-discards” approach
to fisheries management; the need for balance between bycatch reduction and bycatch
utilization initiatives; and concerns arising from incidental catches of marine mammals,
birds and reptiles. The study advocates the development of more robust methods of
estimating discards, allowance for discards in fishery management plans, development
of bycatch management plans and promotion of best practices for bycatch reduction and
mitigation of incidental catches. Global discard estimates could achieve greater precision
through additional studies at national and regional levels.
Kelleher, K.
Discards in the world’s marine fisheries. An update.
FAO Fisheries Technical Paper No. 470. Rome, FAO. 2004. 131 p.

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Contents
Preparation of this document iii
Abstract iv
Acknowledgements viii
Acronyms and abbreviations ix
Foreword xiii
Executive summary xv
1. Introduction 1
2. Method 3
2.1 Summary of the approach 3
2.2 Other definitions and terms used 4
2.3 The discard database 7
2.4 Assumptions and issues related to the method 9
3. Results 17
3.1 Overview of results 17
3.2 Discards in selected regions and countries 24
3.3 Discards in selected fisheries 35
4. Issues 53
4.1 What is “the discard problem”? 53
4.2 Policy issues 53
4.3 Fishery management issues 59
4.4 Bycatch and discard management frameworks 64
4.5 Biological and ecological issues 67
4.6 Technical and economic issues 69
5. Conclusions 75
5.1 Scope of the study
5.2 Principal conclusions 75
5.3 Issues and future direction 76
Annexes
A. Results: supplementary tables 79
B. Evolution of global discard estimates 97
C. Method 103
D. Summary of the reasons for discards 115
References 119

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Tables
1. Generic example of check-sum gap and temporal inconsistency issues 13
2. Estimate of the annual global quantity of discards (tonnes) 17
3. Summary of discards by major types of fishery (tonnes) 19
4. Summary of recorded discards by FAO statistical area (tonnes) 21
5. Fisheries and fishing areas with very low to negligible discard rates 19
6. Breakdown of discard rates by quintile of total quantity of discards 19
7. Frequency distribution of discard rates in shrimp trawl fisheries 36
8. Discard rates and discards in shrimp trawl fisheries 37
9. Discard rates and discards in non-shrimp trawl fisheries 40
10. Discards and discard rates in fisheries for tuna and HMS 45
11. Discards and discard rates in industrial fisheries for small pelagics 46
12. Other industrial fisheries for small pelagics 47
13. Weighted average discard rates for fisheries using different
discard-related management measures 51
14. Summary of discard estimate with confidence limits 79
15. Shrimp trawl fisheries with highest discards (tonnes) 80
16. Non-shrimp trawl fisheries with highest discards (tonnes) and discard rates 80
17. Selected demersal otter trawl fisheries with high discards (tonnes) 80
18. Midwater (pelagic) trawl fisheries with highest discards (tonnes) 81
19. Selected trawl fisheries with high discards (tonnes) 81
20. Discard rates and discards in other fisheries 82
21. Discard rates and discards in gillnet fisheries 82
22. Percentages of hake discards by year class in the Argentine
hake trawl fishery 83
23. Indicative discards by large marine ecosystem (LME) 84
24. Landings, discards (tonnes) and weighted discard rate by country or area
(EEZ, not flag state) 86
25. Commonly discarded species in different fisheries (indicative) 89
26. Incidental catch of seabirds, turtles and marine mammals in selected fisheries 90
27. Examples of discard reduction in selected fisheries
28. Estimated pollock and non-target groundfish total and discarded catch
in directed BSAI pollock fisheries from 1997 to 2000 (tonnes) 94
29. Average rate of incidental catch of halibut, crab and salmon in the directed
BSAI pollock fishery from 1997 to 2000) 94
30. Matrix for calculation of discards as proposed by the Technical
Consultation 99
31. Evolution of discard estimates (tonnes), 1994–2004 100
32. Possible derivation of the estimate of discards (tonnes) referred to in
SOFIA 1998 101
33. Description of the discard database fields 111
34. Number of records by country or area 112
35. Supporting evidence for low or negligible discard rates in certain fisheries 113
36. A classification of causes of discards 116

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Boxes
1. Selected multilateral initiatives 54
2. Guiding principles in Australia’s bycatch policy 65
3. United States – Managing the nation’s bycatch 66
4. European Union – On a community action plan to reduce discards of fish 67
5. Generic framework for a bycatch/discard management plan 68
6. Mesh size and minimum landing size 71
7. Pacific Whiting Fish Harvesting Cooperative 95
8. Specific comments on the Alverson assessment 98
9. Discard estimates in SOFIA 1996 and SOFIA 1998 99
10. Sampling difficulties encountered by observers 105
11. Observer procedure in Canada’s northern shrimp fishery 106
Figures
1. Recorded discards by FAO statistical area 20
2. Recorded discards by large marine ecosystem 85
3. Diagrammatic representation of catch concepts (FAO) 104
4. Evaluation of bycatch 115
5. Causal diagram of discards 117
6. Discard decision framework (United Kingdom) 118

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Acknowledgements
The author wishes to acknowledge the invaluable assistance and advice of the staff of
FAO’s Fisheries Department and, in particular, the professional, consultant and general
staff of the Fishery Industries Division of FAO, without whose help this study could
not have been made.
The author is indebted to the numerous personnel from national fisheries
organizations, consultants and colleagues who supplied reports, “grey” literature, fishery
statistics and expert opinion. The cooperation and inputs from FAO’s regional officers
and field staff, and the directors and staff of many regional fisheries organizations are
gratefully acknowledged. The critical comments of L. Alverson, F. Chopin, J. Cotter, S.
Garcia, J. Pope and A. Smith were invaluable, although their generous assistance does
not necessarily mean that they agree with the interpretations and opinions expressed.
The assistance of S. Venema is acknowledged with respect to South America and
preparation of the bibliography, while the work of F. Teutscher provided a major
information resource. C. Stamatopolous gave advice on statistical interpretation and
V. Kelleher prepared the maps.

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Acronyms and abbreviations
ACCOBAMS Agreement on the Conservation of Cetaceans of the Black Sea,
Mediterranean Sea and Contiguous Atlantic Area
ACFMAFMA Advisory Committee on Fishery Management Australian Fisheries
Management Authority
ASCOBANS Agreement on the Conservation of Small Cetaceans of the Baltic
and North Seas
BOBP-IGO Bay of Bengal Programme Inter-Governmental Organization
BRD Bycatch reduction device
BSAI Bering Sea Aleutian Islands
CBD Convention on Biological Diversity
CCAMLR Commission for the Conservation of Antarctic Marine Living
Resources
CCRF Code of Conduct for Responsible Fisheries
CCSBT Commission for the Conservation of Southern Bluefish Tuna
CECAF Commission for the Eastern Central Atlantic Fisheries (West
Africa)
CFP Common Fisheries Policy (European Union)
CITES Convention on International Trade in Endangered Species of Wild
Fauna and Flora
CMS Convention on (the conservation of) Migratory Species (of Wild
Animals) (Bonn Convention)
COFI Committee on Fisheries
CPUE Catch per unit effort
CRODTDFID Centre de Recherches Océanographiques de Dakar – Thiaroye
Department for International Development
DFO
DSPCM
Department of Fisheries and Oceans
Délégation à la Surveillance des Pêches et au Contrôle en Mer
EC European Commission
EIA Environmental Impact Assessment
EEZ Exclusive Economic Zone
ESA Endangered Species Act (United States)
ETP Eastern Tropical Pacific
EU European Union
FAO Food and Agriculture Organization of the United Nations
FCMA Fisheries Conservation and Management Act (Magnuson–Stevens
Act)
FIGIS Fisheries Global Information System (FAO)
FIS Fish Information & Services
FMC Fishery Management Council (United States)
FMP Fishery management plan
GEF Global Environment Facility
GOA Gulf of Alaska
GRT Gross registered tons
HMS Highly migratory species

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IATTC Inter-American Tropical Tuna Commission
IBSFC International Baltic Sea Fishery Commission
ICCAT International Commission for the Conservation of Atlantic Tunas
ICES International Council for the Exploration of the Sea
ICES CM ICES Council Meeting
ICES WG ICES Working Group
IDCA International Dolphin Conservation Act
IDPPEIDRC Instituto de Desonvolvimento de Pesca Pequena Escala
International Development Research Centre
IFREMER French Research Institute for Exploitation of the Sea
IIFFET International Institute of Fisheries Economics and Trade
IMARPE Instituto del Mar de Perú
INPFC International North Pacific Fisheries Commission
IOTC Indian Ocean Tuna Commission
IPHC International Pacific Halibut Commission
IPOA International Plan of Action (FAO)
ISSCFGITQ International Standard Statistical Classification of Fishing Gear
Individual transferable quota
IUCN World Conservation Union
IUU Illegal, unreported and unregulated (fishing)
IWC International Whaling Commission
LIFDC Low income food deficient country
LME Large marine ecosystem
LOS Law of the Sea
MCS Marine Conservation Society
MLS Minimum landing size
MMPA Marine Mammal Protection Act (United States)
MMS Minimum mesh size
MPA(s) Marine protected area(s)
MPEDAMSA Marine Products Export Development Authority (India)
Magnuson–Stevens Act (United States)
NAFO Northwest Atlantic Fisheries Organization
NEAFC
NGO
Northeast Atlantic Fisheries Commission
Non-governmental organization
NMFS National Marine Fisheries Service (United States)
NOAA National Oceanic and Atmospheric Administration (United States)
NPFMC North Pacific Fisheries Management Council
NRI Natural Resources Institute
OECD Organisation for Economic Co-operation and Development
PFMC Pacific Fisheries Management Council
PWCC Pacific Whiting Conservation Cooperative
RFB Regional fisheries body
RF(M)O Regional fisheries (management) organization
SEAFDEC Southeast Asian Fisheries Development Centre
SEFSC Southeast Fisheries Science Center (United States)
SERFC Southeast River Forecast Center (United States)
SFA Sustainable Fisheries Act (United States)
SGDBI Study Group on Discard and By-catch Information (ICES)
SGFEN Subgroup on Fishery and Environment

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SOFIA The State of World Fisheries and Aquaculture (FAO)
SPC South Pacific Commission
SPREP South Pacific Regional Environment Programme
SSC Species Survival Commission
SSD Seal saver device
STECF Scientific, Technical and Economic Committee for Fisheries
TAC Total allowable catch
TED Turtle excluder device
UN United Nations
UNCED United Nations Conference on Environment and Development
UNCLOS United Nations Convention on the Law of the Sea
UNEP United Nations Environment Programme
UNGA United Nations General Assembly
UNIA United Nations Implementing Agreement
VNIRO Russian Federal Research Institute of Fisheries and Oceanography
WTO World Trade Organization
WWF World Wide Fund for Nature

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Foreword
A global assessment of fisheries bycatch and discards (FAO Fisheries Technical Paper No.
339) was published a decade ago with the hopes of stimulating further investigation of
these serious problems. Since its publication, fishery scientists throughout the world,
conservation and environmental organizations and members of the fishing industry have
extensively referenced the report. However, these estimates no longer constitute a true
reflection of current global discard levels and continued citation of the paper’s estimates
as such is inappropriate.
The estimates provided in the 1994 paper were largely based on data from the late
1980s and it was made clear that these estimates were of a provisional character. In
1996, a FAO Technical Consultation held in Tokyo noted that discards may have been
overestimated for some FAO statistical areas in the report and there was strong evidence
that discards were declining in many fisheries. FAO’s 1998 publication The State of
World Fisheries and Aquaculture attempted to update the much-cited 1994 discard
estimate of 27 million tonnes and provided a revised estimate of 20 million tonnes. The
senior author of the technical report also published several updates, noting a variety
of factors that may have led to a decline in global discard levels during the late 1990s.
This FAO update on global discards on a fishery-by-fishery basis also supports the
affirmation that global discards have significantly declined in recent years.
The reasons cited for this decline have included: (i) greater utilization of bycatch
species in Asia and elsewhere for both aquaculture and human consumption; (ii)
adoption of more selective fishing technologies and methods; (iii) a decline in the
intensity of fishing for some species having high bycatch rates; (iv) a variety of
management actions that prohibit discarding in some countries, set bycatch quotas,
impose time/area closures, and establish marine protected areas and no trawl zones; and
(v) more progressive attitudes by fishery managers, user groups and society towards the
need to solve discarding problems.
Indeed, with some exceptions, discards in most fisheries in China and Southeast Asia
are now considered to be negligible and bycatch landings have increased significantly in
many developing countries. Major fishing nations such as Norway, Iceland and Namibia
prohibit discards and bycatch reduction devices are mandatory in many Australian,
European and Northwest Atlantic Fisheries Organization (NAFO) area fisheries.
Numerous national and international workshops have taken place to solve bycatch and
discard problems.
Thus, it is disturbing to note that so many scientists revert to 15-year old data in order
to document possible current discard levels. These old estimates are frequently cited by
various advocacy groups to decry the state of the world’s fisheries and the use of terms such
as “dirty fishing” merely undermines the considerable efforts and investments of many
responsible fishers, dedicated gear technologists and fishery managers to find solutions to
long-recognized problems associated with certain fisheries and fishing gears.
We urge therefore that the 1994 global discard estimates are no longer cited to decry
the state of the world’s fisheries. There is no “one size fits all” solution. Bycatch and
discard problems must be addressed fishery by fishery and we urge that scientists and
advocacy groups alike focus on the successes of the past decade rather than on the
continued citing of data not applicable to fisheries in this century.
D.L. Alverson
S.A. Murawski
J.G. Pope

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Executive summary
Discards represent a significant proportion of global marine catches and are generally
considered to constitute waste, or suboptimal use of fishery resources. A number of
United Nations resolutions have drawn attention to the need to monitor and reduce
discards and unwanted bycatch, in order to assess the impact of discards on marine
resources and promote technologies and other means of reducing them. The previous
FAO estimate1 of discards at a global level (referred to hereafter as “the Alverson
assessment”), based on data prior to 1994, is considered to be outdated.
The present study re-estimated discards at a global level using information from a
broad range of fisheries in all continents.
Selected policy and technical issues are highlighted and suggestions made for future
actions. A road map for achieving further precision in the global estimate is described
and associated initiatives are outlined.
METHOD
The Alverson assessment is based on the use of the FAO Fishstat database of national
catches. This database provides catch (in practice, the live-weight equivalent of landings)
information by country, FAO area and species (or species group). The Alverson
assessment is essentially a function of landings by species. However, there is no a
priori reason why the discarded quantities of a species should bear a relationship to the
landings of target species.
The approach used in this study is based on the premise that discards are a function
of the landings of a fishery, rather than a function of the landings of a particular species.
A fishery is defined in terms of an area, a fishing gear and a target species.
A list or inventory of the world’s fisheries was compiled in a discard database. Each
database record contains quantitative data on: (i) the total landings of the fishery; and
(ii) either the total quantity of the discards or the percentage of the total catch that is
discarded. The total quantity of discards for a given fishery was generally extrapolated
from the results of studies on a sample of the fishing activities.
The sources of the information on landings and discards are provided with respect to
each fishery, so that the estimate can be readily verified, updated or changed, as new or
more accurate information becomes available at national, regional or FAO level.
Discards (or discarded catch) were defined (FAO, 1996b) as being “that portion of the
catch which is returned to the sea” for whatever reason. Post-harvest waste and discards
of recreational fisheries are not included. Information on discards of turtles, seabirds and
marine mammals is included in the database, but such incidental catches are a secondary
target of the study. The study does not quantify either the unseen mortalities caused by
fishing or the survival of discards.
The information contained in the database was compiled from three principal
sources: (i) from scientific literature and from published national fisheries information;
(ii) from reports and “grey” literature available within FAO or publicly available on
the Internet; and (iii) from contacts with experts in national fisheries administrations,
research institutions or regional fisheries organizations, many of whom provided
detailed reports and databases.
The database contains four groups of fields:
• those specifying the fishing area, which include reference to the FAO fishing area
1 Alverson et al., 1994. This publication is referred to hereafter as “the Alverson assessment”.

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codes and the country or Exclusive Economic Zone (EEZ) from which the catch is
reported;
• those describing or designing the fishery, which include reference to the gear and
the target species;
• those quantifying the landings by the fishery and the quantity or percentage of
discards – the sources of the quantitative information are cited;
• other descriptive fields, which give the reasons for discards, relevant management
measures in force, exploitation status of the fishery and other information of
relevance to the analysis.
The fishery-by-fishery approach encountered several difficulties in data
compilation:
• the sheer scale of the task of compiling a list of the world’s fisheries and quantifying
the landings of each one;
• the absence or inaccessibility of information on discards for many fisheries;
• the lack of published national fisheries catch statistics on a fishery-by-fishery
basis;
• the failure of numerous publications to distinguish clearly between discards and
bycatch; and
• the narrow focus of some studies on the discards of target or commercial species
only.
To facilitate the discard estimates, certain assumptions were made, and use was made
of fisheries information that had already been aggregated, specifically:
• in the absence of information to the contrary, artisanal fisheries were assumed to
have a discard rate of 1 percent or less than 1 percent of the catch;
• in the absence of information to the contrary, “fishmeal fisheries” were assumed to
have a discard rate of 1 percent or less than 1 percent of the catch;
• with some exceptions, Southeast Asian fisheries were considered to have a discard
rate of 1 percent of the catch;
• tuna and other highly migratory species (HMS), and other fisheries for which
statistical information has been collected by regional fisheries bodies (RFBs) were
generally aggregated by ocean; and
• fisheries, in the opinion of the author considered to be substantially similar in
terms of fishing grounds, target species, fishing area, socio-economic basis and
management regime, were considered to have a similar discard rate.
RESULTS
Over 2 000 records of fisheries were compiled of which 1 275 contain quantitative
information on either landings or discards. Of these records, 788 are quantitatively
complete, i.e. they contain quantitative information on both landings and discards for
a given fishery. Countries with such complete sets of information include Norway,
Iceland, the South Pacific Island states, Thailand, Malaysia and Viet Nam. In the case
of the Southeast Asian countries this “completeness” is based on assumptions made
by national fisheries authorities regarding low discard rates, rather than on empirical
information on discard quantities. There are 62 records that refer exclusively to numbers
of marine animals caught incidentally (marine mammals, seabirds and turtles).
Based on the set of complete records, the sum of the recorded discards is 6.8 million
tonnes with respect to total recorded landings of 78.4 million tonnes. The global
weighted discard rate is 8 percent.
Applying the global weighted discard rate estimated in this study (8 percent) to a
ten-year average of the FAO Fishstat2 reported global nominal catch, total extrapolated
discards are 7.3 million tonnes. Some caution is required in extrapolating from the total
2 Fishstat Plus (version 2.3) of 24 July 2003. The nominal catch value excludes marine animals and plants.

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global catch, as certain major fish producer countries are not adequately represented in
the database. These include the Democratic Republic of Korea, the Republic of Korea
(no discard information), the Russian Federation, New Zealand and the Philippines. The
European Union (EU) member countries and India have only partially been covered. A
number of small fish-producing countries are not included.
Shrimp and demersal finfish trawl fisheries account for over 50 percent of total
estimated discards while representing approximately 22 percent of total recorded
landings. Tropical shrimp trawl fisheries have the highest discard rate and alone account
for over 27 percent of total estimated discards. Small-scale fisheries generally have lower
discard rates than industrial fisheries. Purse-seine, handline, jig, trap and pot fisheries
have low discard rates. In geographical terms the highest discards are in the Northeast
Atlantic and Northwest Pacific, which jointly account for 40 percent of discards (FAO
areas 27 and 61, respectively).
At the global level it was not possible to compile a time series on discards to enable
an empirical assessment of global trends in discards to be established. Nevertheless,
two trends are apparent. There has been a reduction in bycatch and in discards in
many fisheries, particularly those in developed countries. There is increasing utilization
of bycatch and a consequent reduction in discards in many fisheries, particularly in
developing countries. Several time series of discard data for selected fisheries are provided
in support of these conclusions. A decrease in effort and change of target species in some
major trawl fisheries has also resulted in a reduction of discards. Changes in fisheries
regulatory regimes, requiring more selective fishing and prohibiting or curtailing
discards, have also contributed to discard reduction.
The Alverson assessment, published in 1994, estimated discards to be 27 million
tonnes (range 17.9 and 39.5 million tonnes). A subsequent (1998) FAO estimate
suggested a reduced estimate of 20 million tonnes and a further study by Alverson in
1998 indicated that the 1994 assessment was an overestimate. Because of differences
in method, the estimates provided in this report are not directly comparable with the
Alverson assessment and consequently the extent to which the estimates represent a
reduction in discards is not known.
The main spreadsheet file of the discard database and a bibliography are provided
on the accompanying CD-ROM. The spreadsheet file is supplemented by numerous
country and fishery files as well as files generated from databases supplied by the
regional fisheries organizations or derived from national fisheries statistics. These files
and source materials, including electronic copies of reference materials, are archived
within FAO, classified by continent, country or regional fisheries organization. A
searchable bibliography was compiled using bibliographic software.
POLICY IMPLICATIONS
The “discard problem” embraces several issues or subproblems:
• the moral problem of responsible stewardship of marine resources;
• designing a management regime that limits or prevents discarding while meeting
multiple social, economic and biological objectives;
• the practical problem of enforcing regulations designed to prevent or minimize
discards, particularly as discards occur at sea where enforcement is most difficult;
• the technical problems of gear selectivity and utilization of species with a low
market demand through transformation or adding value; and
• the economic problems posed by efforts to reduce bycatch, increase landing of
bycatch or increase utilization of bycatch.
Moral issues
International instruments, including United Nations (UN) resolutions, the Kyoto
Declaration and the Code of Conduct for Responsible Fisheries (CCRF) have

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highlighted the need to reduce or minimize discards. These instruments reflect the idea,
enshrined in many of the world’s religious and secular beliefs, that wastage of natural
resources is morally wrong.
A number of countries have instituted fisheries policies and management regimes
based on the principle of “no discards”. A “no-discard” policy implies a paradigm shift
in approaches to fisheries management. It moves the focus of management measures
from landings to catches and from fish production to fish mortality. In conformity with
the precautionary approach, by regarding “no discards” as the norm, any discarding
then requires adequate justification.
Issues related to the Code of Conduct for Responsible Fisheries
There are two principal approaches to addressing the “discard problem”:
• reducing bycatch
• increasing utilization of bycatch
These two harvest strategies may be complementary and in any given fishery
an appropriate balance between bycatch reduction and utilization is required. The
biological and social principles upon which such a balance can be based require further
analysis and development of decision frameworks. A more precise interpretation of “the
ecosystem approach” in terms of the trade-off between promoting bycatch reduction
and promoting bycatch utilization may be of value. In particular, the balance between
highly selective fishing that targets one trophic level (or species) only, and less selective
fishing that is likely to impact upon several trophic levels (or species groups), may
require further attention to enable best scientific advice to be made available.
A third approach is to improve the survival of discards and animals returned to
the sea. This is of particular importance with regard to species groups such as marine
mammals, turtles, seabirds, lobsters and crabs.
Responsible fishing operations (in relation to discards and bycatch) can be based on
the following principles:
• making efforts to avoid unwanted catches – in particular, catches of endangered
species and unwanted catches and discards that may reduce biodiversity or disrupt
ecosystem function or integrity;
• where catches of unwanted species, sizes or sexes are unavoidable, making efforts
to find sui uses for such animals, and/or if there is a reasonable probability of
survival, making efforts to return the unwanted catch to the sea;
• taking measures to increase the survival of unwanted catch destined to be returned
to the sea;
• keeping records of discards, if required for management purposes.
The incidental catch and subsequent discard of charismatic, protected or endangered
species, such as turtles, marine mammals and seabirds, are likely to have an increasing
impact on fishing activities and trade in fish products. The absence of a neutral and
internationally accredited mechanism for compilation of information on the incidental
catches of many of these species and for examination and promotion of best practices in
mitigation measures may impede rational discussion and development of solutions.
TECHNICAL IMPLICATIONS
Discard information has a high inherent level of variability requiring high levels of
discard sampling to give accurate assessments. On-board observer reports are considered
indispensable for accurate estimation of discards. Relationships between discard rates
and other variables (e.g. landings, duration of trip, length of trawl tow, market prices)
tend to be weak. Consequently, raising or extrapolating discard estimates derived from
samples to the level of the fleet or fishery may have a high degree of error. Accuracy is
dependent on the design of an appropriate sampling protocol.

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Discards account for a significant mortality in fisheries. For numerous reasons
discard estimates may not be included in stock assessments, TAC determination or
quota management. In general, the “accounting toolkit” for discards is deficient.
National fisheries statistics are generally collected, compiled and presented on a
species-by-species or species group basis. There are several advantages in also compiling
national fisheries statistics on a fishery-by-fishery basis. In particular, this may focus
attention on the definition of coherent management units, link trends in landings to
fishery-specific management measures and facilitate inclusion of discard estimates if
required.
The discard database includes information on fishery management measures
associated with discards and bycatch. The measures include legal obligations (e.g.
minimum landing sizes, quotas and transhipment prohibitions), economic incentives
and technical improvements (e.g. bycatch reduction devices [BRDs]). A number of
fisheries have specific bycatch plans or require environmental impact assessments that
specifically address bycatch and discard issues.
FUTURE DIRECTIONS
The development of guidelines on best practices can be considered with regard to:
• discard sampling, e.g. from observers, logbooks, fishers’ estimates;
• raising of discard estimates to the fleet or fishery level;
• use of discard estimates in stock assessments;
• use of discard estimates in total allowable catches (TACs) and quotas;
• development of bycatch management plans; and
• introduction and adoption of bycatch reduction and incidental catch mitigation
technologies and practices.
A series of related studies can be considered to supplement this study, in particular,
to compile:
• information on the interaction between fishing activities and charismatic species at
fishery, ocean and global level, with a focus on effective mitigation measures;
• information on unobserved mortalities caused by fishing activities; and
• additional information on survival of discards.
This study is regarded as an evolving tool rather than a static report. Ideally, it requires
a further “decentralized” phase at national or regional level to: (i) verify or update the
information in the discard database; (ii) give a broader “ownership” base to the discard
information, through dialogue and consultation with national fisheries administrations
and regional fisheries organizations; and (iii) compile discard information from countries
and fisheries where information is deficient.
The global fishery-by-fishery records of landings form the backbone of the discard
database. This set of records is of potential use for a range of other analyses, in particular
if fields such as “status of exploitation of the fishery” are complete. Efforts are under
way to integrate the database into FAO’s Fisheries Global Information System (FIGIS)
both as a basis for compiling the global inventory of fisheries and as a discard database
subset. Records in the database may be biased towards discards, since many of these
records are derived from “discards literature”.

1
1. Introduction
“It is impossible to estimate the quantity of small fish that is destroyed since it is impossible to
estimate the amount that is shovelled overboard, dead or dying.”
(Holt, 1895)
Discards are that portion of the total catch which is dumped or thrown overboard
at sea. Discards are generally considered a waste of fish resources and inconsistent
with responsible1 fisheries. However, while technically a discard, the return of an egg-
bearing lobster to the sea is clearly supportive of responsible fisheries.
WHY IS AN UPDATE OF GLOBAL DISCARDS NEEDED?
FAO is required to report periodically to the United Nations General Assembly
(UNGA) on progress with regard to UN resolutions on fisheries. A number of these
resolutions (see Section 4.2.1) make reference to monitoring bycatch and discards,
including provisions on bycatch and discards in international fisheries instruments, and
reviewing the impact of bycatch and discards on the sustainable use of living marine
resources.
This update helps to quantify the scale of discards in different types of fishing
operations and in different regions and provides an indication of the progress made
in reducing discards and wastage in the world’s capture fisheries. These trends are of
interest for the design of national and multilateral initiatives to promote responsible
fishing operations and utilization of the catch. Estimating discards also raises practical
issues with regard to the interpretation, application and monitoring of the Code of
Conduct for Responsible Fisheries (CCRF).
PREVIOUS ESTIMATE
In 1994 FAO published an estimate of global discards in marine fisheries (Alverson et
al.)2 indicating that 27 million tonnes, or approximately 27 percent of the global catch,
were discarded annually. The initial estimate was a major achievement, providing the
order of magnitude for the estimate of global discards and illustrating the difficulty in
estimating global discards, as indicated by the wide range of the estimate (17.9–39.5
million tonnes). In particular, the Alverson assessment helped to reduce global discards
by focusing attention on the potential magnitude of the “discard problem”.
The 1994 estimate was based on data from the 1980s and early 1990s and cannot
accurately reflect the changes that have occurred in world fisheries. However, the
estimate continues to be cited in support of particular policies and actions. The
Alverson assessment was also subject to criticism with respect to aspects of the
estimation method, including the assumptions on which the assessment was based and
the limited geographical coverage of the available discard information.
1 UN General Assembly Resolution 49/118 (UNGA, 1994). There are numerous references to discards in
the Code of Conduct for Responsible Fisheries (CCRF).
2 Alverson et al., 1994 (referred to hereafter as “the Alverson assessment”). While the primary author
made subsequent revisions of the estimate, the 1994 estimate is that which is most frequently cited in the
literature. A previous estimate was also made by Saila (1983).

Discards in the world’s marine fisheries – an update
2
CURRENT STUDY
The objectives of the current study were to develop an improved and more robust and
transparent method for estimating discards at the global level, and to use the method
to re-estimate discards in the world’s marine capture fisheries.
The approach used in this study differs substantially from that used in the Alverson
assessment, which was based on discard/catch ratios determined by species or species
group. These ratios were then applied to FAO’s Fishstat nominal catch statistics for the
1988–1990 period in order to derive the global estimate.
In contrast, the current study compiled an inventory of the world’s fisheries and
their respective catches. Information on the quantity of discards or the proportion of
discards in the catch was obtained from available discard studies. As discard studies
were not available for all fisheries, in some cases the ratio of discards to catch was
assumed, based on information from similar fisheries. The total quantity of discards for
the fishery was calculated by raising (extrapolating) the results of the discard studies to
the total recorded landings for the fishery, as extracted from national fisheries statistics
and other sources.
The fishery-by-fishery approach offers the possibility of verification and periodic
updating of the discard estimates at the country or regional level in consultation with
national fisheries authorities and regional fisheries organizations.
While it is unlikely that a definitive estimate of discards at the global level can be
made, the re-estimate is seen as a contribution to an ongoing FAO process3 to focus
attention on the scale of discards, trends in discarding and on fisheries management
issues and practices associated with discards.
3 See UN resolutions, Section 4.2.1.

3
2. Method
2.1 SUMMARY OF THE APPROACH
The method is summarized in this subsection. Because there are significant differences
between countries with regard to the interpretation of key terms, definitions are
further discussed in Section 2.2. Reference is also made to Annex C, where details
of the discard database file structure and a diagrammatic representation of the catch
concepts are presented.
2.1.1 Key definitions
The key concepts and definitions are summarized below.
The definition of discards used in this study is adapted from FAO Fisheries Report
No. 547 (FAO, 1996b).
Discards, or discarded catch is that portion of the total organic material of animal origin in the
catch, which is thrown away, or dumped at sea for whatever reason. It does not include plant
materials and post harvest waste such as offal. The discards may be dead, or alive.
Discarding is considered to be an act of volition requiring a decision by fishers
to reject or dump the fish. Discards include slipped fish, i.e. fish caught in a net and
subsequently released into the sea without being brought on board the vessel. Discards
do not include dead corals or empty shells. The release of fish by recreational fishers
has not been considered as a discard for the purposes of this study.
Bycatch is the total catch of non-target animals. Discards are not a subset of bycatch
since the target species is often discarded.
Discard rate is the proportion (percentage) of the total catch that is discarded.
Catch. The term “catch” is used to refer to the “gross catch” as indicated in FAO’s
diagrammatic presentation of catch concepts (see Annex C, Figure 3, and Section 2.2.4).
Catch includes all living biological material retained or captured by the fishing gear,
including corals, jellyfish, tunicates, sponges and other non-commercial organisms,
whether brought on board the vessel or not. Plant material is not considered part of
the catch for the purposes of this study.
Landings refer to the portion of the total catch brought ashore or transhipped from
the vessel. The landings information contained in the discard database is derived from
a range of different sources. For a given set of “catch statistics” it may be difficult to
determine whether the values are landed weights or the live-weight equivalent of the
landings (= nominal catch as used in Fishstat).
Fishery. The fishery is used as the principal unit of account for the discard database.
A fishery is defined as a combination of a fishing area or zone plus a fishing gear plus
a target species.
2.1.2 Sources of information
Information on discards and associated catches and landings by fishery was compiled
from a broad range of sources. These included papers published in scientific journals,
official publications of national fisheries administrations, “grey” or unpublished

Discards in the world’s marine fisheries – an update
4
Method 5
literature, reports of scientific working groups, catch and discard databases and
correspondence and contacts with national and international fisheries experts. Over
3 000 references were compiled in a searchable bibliographic database archived in
FAO.
2.1.3 The discard database
Records of over 2 000 fisheries were compiled in a discard database. Each record
represents one fishery. The record identifies the fishery in terms of its location,
fishing gear used and target species. The key quantitative fields provide the tonnage
of the landings and discards for each fishery. Reference fields indicate the source of
the landings and discard information and the year(s) to which they refer. A “discard
rate” field indicates the percentage of the catch that is discarded (effectively discards
as a percentage of discards plus landings). Other fields record additional qualitative
information, such as the species composition of the discards and reason for discarding.
The structure of the database is presented in Annex C.4.
2.1.4 Raising and key assumptions
The proportion of discards in the catch was obtained from discard studies. The studies
were generally based on a sample of the vessels, fishing trips or fishing activities in
the fishery. This proportion or discard rate was applied to the total landings of the
fishery to raise or extrapolate the tonnage of discards to the level of the fishery. A linear
relationship between discards and landings was assumed (see Section 2.4.1 for further
discussion of the assumptions). In some cases, notably in small-scale and artisanal
fisheries, the proportion of discards in the catch was assumed based on information
from similar fisheries.
2.1.5 Verification
Information was checked by the use of multiple information sources for some records,
further scrutiny of apparent anomalies (e.g. exceptionally high or low discard rates),
by direct contacts with the authors of publications on discards, and by comparisons
between extracts from Fishstat and the records. For selected countries the information
was checked by requesting verification on the content of the discard database records
from the national fisheries authorities or research institutes.
2.1.6 Differences between current and previous estimates
The main difference between the current method and the 1994 estimate is the use of
the fishery-by-fishery approach, in contrast with the species or species group approach
used in 1994. The information on which the current estimate is based has a substantially
broader geographical range and is more representative of the world’s fisheries. The
evolution of discard estimates is detailed in Annex B.
2.2 OTHER DEFINITIONS AND TERMS USED
2.2.1 Other definitions of discards and bycatch
The term “discard” has distinctly different meanings in different jurisdictions, resulting
in frequent confusion between “discard” and “bycatch”. This confusion pervades the
literature and has resulted in considerable difficulty in the course of the study.
The Nordic workshop (Nordic COuncil of Ministers, 2003) defined “discard” as:
“the proportion of the catch which is taken on board, or brought to the surface by the vessel and
which is subsequently thrown back to sea, dead or dying, or likely to die”.
The definition includes “slipped catches” as discards and is essentially the same as
that given above and used in this study.
In contrast, the United States of America Magnuson–Stevens Act (MSA), Section
3(2), (1996) defines bycatch as:

Discards in the world’s marine fisheries – an update
4
Method 5
“fish which are harvested in a fishery, but which are not sold or kept for personal use, and
includes economic discards and regulatory discards. Such term does not include fish released
alive under a recreational catch and release fishery management program”.
This effectively means that bycatch is equivalent to discards under the Act. This
definition has been reinterpreted (NMFS, 1998) in the United States within the context
of specific fishery management plans and publications, for example:
“Bycatch: discarded catch of any living marine resource plus retained incidental catch and
unobserved mortality due to a direct encounter with fishing gear.”
The Inter-American Tropical Tuna Commission (IATTC) refers to “discards” as
commercially important tuna species only (i.e. yellowfin, skipjack, bigeye, bluefin and
albacore) that are dumped dead at sea, while “bycatch” is considered to be fish and
other animals other than commercially important tunas that are dumped dead at sea.
A recent European Commission (EC) paper (European Commission, 2002a) defines
discards as commercial species retained by a fishing gear that have been brought on
board a fishing vessel and are thrown back into the sea, effectively ignoring non-
commercial species.
Other definitions of bycatch
In Australia’s bycatch policy, the term “bycatch” refers to all non-targeted catch
including by-product, discards and the biomass that does not reach the deck of the
fishing vessel but is affected by interaction with the fishing gear.
Bycatch is sometimes defined as “discarded catch plus incidental catch” where
incidental catch is considered to be retained non-target species. However, if target
species (e.g. juveniles) are discarded this may cause some confusion, as target species
are not usually considered to be “bycatch”.
Three further terms are used in this study to describe discards, or discard practices.
• Regulatory discards. Catch that is required by regulation to be discarded (from the
Sustainable Fisheries Act [SFA], United States).
• Discretionary discards. Catch that is discarded because of undesirable species, size,
sex or quality, or for other non-regulatory reasons (NMFS, 1998).
• Highgrading. Discarding of lower value commercial catch to maximize the
value of quota. Highgraded discards are part of “discretionary discards” and are
common in fisheries managed through individual vessel quotas.
2.2.2 Discard rates
The term “discard rate” used throughout this report refers to the weighted discard rate.
The weighted discard rate is derived from the set of complete records for the type of
fishery and is the summed discards as a percentage of summed landings plus summed
discards.
Weighted discard rate (%) = Summed discards (tonnes) x 100
Summed discards + summed landings (tonnes)
The term “average discard rate” is the average of the individual discard rates for a set
of fisheries. Average discard rates are provided together with their respective standard
deviations for several of the major types of fishery.
2.2.3 Fishery and métier
The basic thesis on which the re-estimate is based is that discards are specific to a
fishery. The fishery is used as the principal unit of account for the discard database.
4 Concerns with the terminology used to identify bycatch or discards were addressed at a bycatch
workshop in the United States in 1992. The terminology was subsequently updated by Alverson et al.
(1994). Also see McCaughran, 1992.

Discards in the world’s marine fisheries – an update
6
Method 7
A fishery is defined as a combination of a fishing area or zone plus a fishing gear plus
a target species. The term “fishery” is considered to be equivalent to the French term
“metier”.5
A range of analyses can be used to identify fisheries (Pelletier and Ferraris, 2000;
Rochet et al., 1994; Laurec, Biseau and Charuau, 1991). Because of the lack of such
empirical analyses for many countries and areas, the fisheries listed in the discard
database were generally identified on the basis of descriptions of the fisheries sector
prepared by the national fisheries administrations, e.g. in national fisheries development
or management plans, in national fisheries statistics, or in research reports. Essentially,
most of the fisheries listed in the discard database were identified by the competent
national fisheries authorities.
Despite the fact that the fishery is an important focus of fishery management, many
fisheries administrations do not necessarily compile catch or landings information by
fishery. Consequently a substantial number of database entries refer to aggregate or
generic fisheries, e.g. “the inshore small-scale, multigear, multispecies fishery”.
Industrial fisheries
Industrial fisheries are large-scale fisheries that use large mechanized fishing vessels
as distinct from small-scale and artisanal fisheries. Note that in the EU, the term
“industrial fishery” may be used to refer to fisheries for small pelagics harvested for
the manufacture of fishmeal.
Small-scale fisheries
This generic term is used in the study to characterize a highly diverse group of
fisheries. The definition is essentially country specific, i.e. the country considers the
fishery to be “small-scale”. The terms “artisanal fisheries” and “small-scale fisheries”
are considered equivalent for the purposes of this study and embrace other categories
(e.g. subsistence, traditional, indigenous) as used in national fisheries statistics, or in the
fisheries terminology of different countries. It is recognized that the term “small-scale”
refers to “scale” rather than the nature of the fishing operation itself, e.g. the family
nature of artisanal fisheries.
2.2.4 Other terms used
Landings
Landings values in the discard database are reported as given in the source of reference,
except in rare cases such as when lobster or shrimp catches are reported as tail weight.
In such cases the reported landings are converted to live-weight equivalent.
It is not always clear whether the mass of landings or catches reported in national
fisheries statistics or other sources used is the “gross catch”, the “landings” or the
“nominal catch” as per FAO definitions (see Annex C, Figure 3, which gives a
comprehensive graphical illustration of the different catch concepts). Fishstat provides
statistical information on catches as “nominal catches” by species and country. The
nominal catch is the live-weight equivalent of the landings.
No attempt has been made to adjust for additional catches or landings arising from
illegal or unreported fishing activities, or for possible inaccuracies in national fisheries
statistical information as no adequate information is available at a global level. The
principal reasons for this are the lack of any standardized reporting of such catches
at global, regional or national level and the inability to resolve conflict with official
reports of national fisheries catches.
5 For a discussion of different definitions and approaches to defining fisheries see ICES, 2003. The ICES
study group proposed a narrower definition of the term “métier”: a “homogenous subdivision of a
fishery by vessel type (e.g. by vessel size)”. ICES also uses the term “fishery units” and has distinguished
such units in terms of fishing depth.

Discards in the world’s marine fisheries – an update
6
Method 7
Target catch
This term refers to catch of a species, a particular size or sex, or an assemblage of
species that is primarily sought in a fishery, such as shrimp in a shrimp fishery or
mature female fish in a roe fishery. The definition of targeted catch within a fishery
is not static, as in a multispecies fishery, the mix of species targeted and caught may
change over time.
Incidental catch
This term is used in the context of rare incidents or events such as catches of marine
mammals, turtles or seabirds. Incidental catch is generally expressed in numerical terms
rather than in terms of weight. Incidental catch is usually discarded and is considered
as a discard for the purposes of this report.
Slipped catch
This term is applied to catches (usually purse-seine catches) that are released in the
water without being taken on board the vessel. Slipped catches are considered to be
discards. Quantities of slipped fish are difficult to estimate.
Trash fish
This term is not generally used in the study but refers to non-commercial or very
low-value fish, usually caught by a trawl fishery. Trash fish is usually discarded unless
collected at sea, or landed for aquaculture feed or fishmeal manufacture.
Debris
This term is used in the restricted sense of non-organic materials caught during fishing
operations. Examples include rocks, sand, mud and plastic bottles. Organic materials
such as dead shells, dead coral and plant materials (seaweed) are also considered
debris.
Endangered and charismatic species
Endangered species6 are those threatened with local or global extinction. Charismatic
species,7 sometimes referred to as “icon species”, are species that for cultural or
religious reasons society accords an existence value substantially in excess of market
value (e.g. dolphins, seals, albatrosses).
2.3 THE DISCARD DATABASE
2.3.1 Structure of the discard database
An inventory of the world’s fisheries was compiled8 and a search conducted for
quantitative information on landings and discards from each fishery. The information
was stored in the form of a master spreadsheet and with numerous supporting
spreadsheets. The master spreadsheet is referred to as the “discard database” and
contains 33 fields. The field structure is detailed in Annex C.4, Table 33. The fields can
be divided into six categories.
• Area. Fields contain information on area, including the FAO statistical area code,
national or regional fishery statistical areas and the name of the country.
6 The Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) does
not define the term “endangered species”. The World Conservation Union (IUCN) also uses the terms
“threatened” and “vulnerable” in categorizing endangered species.
7 The term “charismatic discards” was used by Hall (1996).
8 No comprehensive inventory or list of the world’s fisheries has previously been compiled. A global
inventory of fisheries is gradually being developed under the FAO Fisheries Global Information System
(FIGIS, http://www.fao.org/fi/figis).

Discards in the world’s marine fisheries – an update
8
Method 9
• Fishery. Fields describe the fishery, including the name of the fishery, the type of
gear and the target species.
• Landings. Fields contain information on the landings of the fishery including the
quantity of landings in tonnes, year of reference and source of information.
• Discards – quantitative. Fields contain information on discards in the fishery:
quantities in tonnes; the basis for estimation of the discards (e.g. observer reports,
research survey); the reference to the source of the information; and the year or
period to which the discard information refers.
• Discards – descriptive. Fields contain information on the reason for the discards,
the measures or policies relating to discards and information on the status of
exploitation of the fishery.
• Flags. Fields used either to distinguish particular records (e.g. those referring to
incidental catches of marine mammals, or to small-scale fisheries).
The supporting spreadsheets were used to transform the landings and discard
information provided in the source material to the formats and units required in
the discard database. For example, some studies present discards as numbers of fish
of different sizes, requiring a transformation from numbers discarded to weights
discarded. The format and content of the subsidiary worksheets vary in relation to the
different source materials.
2.3.2 The records in the discard database
There are over 2 000 records in the discard database of which 1 275 contain quantitative
information on either landings or discards. The remaining records list fisheries for
which quantitative information was not recorded.
Of these 1 275 records, 788 are quantitatively complete, i.e. they contain quantitative
information on both landings and discards for a given fishery, 1 274 records contain
information on catches, while 839 contain information on discard quantities. Some
records are considered to be “duplicates”, i.e. there is more than one record for the
same fishery, either for different time periods, or providing information from different
authors or sources. Sixty-two records refer exclusively to numbers of marine animals
caught incidentally (marine mammals, seabirds, turtles). Excluding duplicates and
incidental catch records, 956 records contain catch information, while 755 records
contain discard information. Some records are used for summary or checking
purposes.
2.3.3 Scope of the database
The primary focus of the study is on commercial and subsistence marine capture
fisheries for finfish and shellfish. Records of incidental catch of marine mammals,
turtles, seabirds and protected species are included because of the growing impact
of the catches of these species on fishing activities. All such incidental catches are
considered to be discarded.
The study does not cover freshwater and recreational fisheries. The importance of
catches and discards in some recreational fisheries is recognized, but few countries9
maintain adequate records. Freshwater species, species that migrate between freshwaters
and marine habitats, reptiles, amphibians and aquatic plants have been excluded from
Fishstat values and other values used.
Post-harvest waste, such as offal, guts, frames and waste from surimi processing, is
not considered a discard. Roe fisheries (e.g. herring, or United States rock sole) may
have substantial wastage of males, which are not considered as discards since much of
the sorting takes place onshore.
9 See Alverson, 1998. Exhibit 22 gives aggregate discard rates for United States Atlantic recreational
fisheries of 60 percent (Northeast) and 52 percent (Southeast).

Discards in the world’s marine fisheries – an update
8
Method 9
Shark finning
In theory, the practice of shark finning may not be considered different from filleting
and gutting. The shark carcass would then be considered as “offal” or waste of a
processing operation rather than as a discard. However, in this study, finned sharks are
considered to be discards because most of the edible portion is discarded and because
of the widespread condemnation10 of and legislation11 on what is considered a wasteful
practice.
No allowance has been made for the quantities of fish killed through interactions
with fishing gear that does not result in their capture. These unobserved mortalities
may be caused by the impact of trawl gear on the bottom, escapement or drop-out
from nets, ghost fishing by lost nets and similar gear inefficiencies (e.g. there are high
scallop mortalities associated with scallop dredges).
Both fishers and observers tend to focus on commercial species and recognized
animals. There is a tendency to group tunicates, sponges, echinoderms, hermit crabs,
worms and corals with jellyfish12 and perceive such biomass as debris, rather than
as organic material. These non-commercial animals are frequently ignored and not
recorded as discards during studies. This biomass tends to be omitted from estimates
of discards. Many of these animals also pose practical problems of measurement of
the biomass concerned (e.g. jellyfish), but may constitute a significant proportion
of the total biomass harvested by trawls (Prena et al., 1999). The literature contains
relatively few estimates of invertebrate discards and discards of unusual species such as
sea snakes. Because of a lack of information the estimates have made no allowance for
such unperceived or unrecorded discards.
2.3.4 References and bibliographic archive
To facilitate checking and updating of the discard database each discard database
record contains two bibliographic reference fields indicating: (i) the source of the
catch or landings information; and (ii) the source of the discard rate or discard tonnage
estimate. These bibliographic references and those used in the text of the report have
been compiled in a bibliographic database using a commercial bibliographic software.
Electronic versions of many of the reference materials are organized by continent,
country and several generic categories in an electronic archive held in FAO Fisheries
Department, Fishery Industries Division (FIIT).
2.4 ASSUMPTIONS AND ISSUES RELATED TO THE METHOD
2.4.1 Assumptions and aggregations
Certain assumptions and aggregations were necessary to prepare the discard
estimates.
Correlation between total landings and discards
It is assumed that for a given fishery, during a given period, there is a linear relationship
between landings and discards at the aggregate level. In other words, the discard rate
of a sample has been applied to the total landings of the fishery to derive the total
quantity of discards. This relationship does not necessarily hold true at the level of
individual vessel trips or fishing operations,13 or in relation to the landings of target
species. Furthermore, the linear nature of the relationship is open to question (Trenkel
and Rochet, 2001). For further discussion see Section 2.4.3 on “raising”.
10 See International Plan of Action on Sharks, par. 22.
11 For example, see NOAA, 2002 and Council Regulation (EC), 2003.
12 Up to 30 percent of the catch is comprised of jellyfish in the United States South Atlantic shrimp trawl
fishery (Lassen, SEFSC Web site).
13 For further discussion see Trujillo and Pereda, 1997; Reeves, 1990; and Rochet , Péronnet and Trenkel,
2002.

Discards in the world’s marine fisheries – an update
10
Method 11
Representative sample
Discard rates for a particular fishery are generally based on a sample of discards by
particular vessels. The sample discard rates are assumed to be representative of the entire
fishery for the purposes of raising (extrapolating) the discards to the fleet or fishery
level. While this assumption is essential in order to estimate the quantity of discards
from a given fishery, the assumption is open to a range of criticisms (see Annex C,
Section 2.6 for further discussion of discard sampling). As the quantity of the landings
for which discard estimates have been made (the sample) accounts for 94 percent of the
ten-year average of Fishstat nominal catch, it is assumed that the weighted discard rate
is a representative discard rate for the global marine catch.
Countries and fisheries with low or negligible discard rates
Based on expert opinion from in-country sources, the fisheries in several countries were
assigned a discard rate of 1 or <1 percent (see Annex C.5, Table 35). These countries
include the Pacific Island states, the small island countries of the Caribbean and several
South Asian and Southeast Asian countries. There are some notable exceptions to
the latter category, e.g. the Arafura Sea shrimp fishery (Indonesia) and some Chinese
fisheries and trawl fisheries in the Philippines.
In the absence of information to the contrary, fisheries in the following categories
were also assumed to have discard rates ranging from <1 to 5 percent: (i) artisanal and
subsistence fisheries, in particular those based on coral reef resources and small pelagic
species and those based on collection by hand or by divers; (ii) fisheries prosecuted for
fishmeal; and (iii) fisheries using factory trawlers where minimum size regulations are
not applied.
Comparable fisheries
Fisheries considered to be similar were assumed to have a comparable discard rate, i.e.
a known discard rate from one fishery was applied to a fishery considered to be similar.
Each assumption is essentially a case-by-case subjective judgement by the author based
on personal knowledge of the fisheries, on contacts with experts on the fisheries in
question, or on apparent close similarities between fisheries in terms of area, gear,
target species, markets and regulations as deduced from the literature on these fisheries.
Examples include artisanal reef fisheries, tuna pole and line fisheries for a given ocean,
and the set of Celtic Sea demersal fisheries.14
Generic fisheries
In the absence of more detailed information, fish catches/landings were aggregated
into generic fisheries, e.g. “south coast artisanal multigear multispecies fishery” or “all
industrial trawl fisheries”. It is acknowledged that such groups may contain several
different fisheries with different discard rates. With the help of local experts, future
discard estimates may achieve a greater level of disaggregation and precision.
Fisheries for tuna and highly migratory species (HMS)
Tuna fisheries, fisheries for HMS and other highly dispersed fisheries for which
statistical information has been collected by relevant regional organizations (e.g. by
the International Commission for the Conservation of Atlantic Tunas [ICCAT],
the Indian Ocean Tuna Commission [IOTC], the Inter–American Tropical Tuna
Commission [IATTC], the South Pacific Commission [SPC] and the Commission for
the Conservation of Antarctic Marine Living Resources [CCAMLR]) were generally
aggregated by ocean or major fishing grounds rather than by flag state (e.g. Western
14 An example of an essentially similar methodology applied at an enhanced level of detail is given by
Melnychuck et al., 2001.

Discards in the world’s marine fisheries – an update
10
Method 11
Central Pacific tuna purse-seine fishery). The statistical information collected by the
regional fisheries organizations was used as the basis for these discard calculations.
This means that vessels from several flag states may be grouped into one fishery and
database record. In order to avoid double counting of such catches, tuna and HMS
catches were subtracted wherever possible from catches recorded by country in the
discard database.
2.4.2 Availability and quality of information
A complete discard database record requires two pieces of information: (i) the total
catch or landings by a fishery; and (ii) either the discard rate or the total quantity
discarded by that fishery.
Absence of discard information
There is a general absence of quantitative information on discards or discard rates and
relatively few countries have made comprehensive assessments of discards. Essentially,
many of the difficulties encountered by Alverson in preparation of the 1994 assessment
still exist.
Catch/landings information by fishery
At the country level, aggregate statistical information on fish catches is generally
published by species, fleet or area, but more rarely by fishery. Few lists of fisheries exist
in the published literature, much less the associated quantitative information on catches
or landings. Nevertheless, such information is often available in the unpublished internal
reports of national fisheries administrations. In many jurisdictions fisheries tend to
have an amorphous or fluid definition. This is partly because several different gears
may be used, several species may be targeted on a single fishing trip or by a particular
vessel, and because the fishery changes over time. Consequently the attribution of
catches to a particular fishery may be difficult.
At the global level, FAO nominal catch statistics (Fishstat) are available by area and
species (or species group), but not by fleet, fishing gear or fishery. The FAO database
of fishing vessels contains information on the numbers of decked and undecked vessels
by size class and by type of vessel (e.g. trawler, longliner). The Fishstat (nominal catch)
database and the vessel database are independent of each other. Thus, the Fishstat catch
information cannot currently be linked to a type of vessel or fishery.
Quality and scope of discard information
Studies on discards rarely refer to the total catch of the fishery studied. Even in peer-
reviewed publications, the terms “bycatch” and “discards” are at times used in an
apparently equivalent or interchangeable manner, often rendering the information
unusable without clarification from the authors. In many of the references cited it is
not clear whether the catch values quoted refer to landings, gross catch or nominal
catches.
Many discard studies have a narrow focus on the discards of one or few target
commercial species, which may be reported in numbers, without the information
necessary to convert the discard numbers to weights. Studies frequently ignore non-
commercial finfish species and a significant discarded biomass of invertebrates such as
tunicates, corals, coelenterates (jellyfish), sponges, echinoderms and other commonly
discarded invertebrates.
Information in the published literature is generally incomplete. For example, the
average weight of shark fins and the total weight of shark fins landed may be given,15
15 Xiao-jie and Zhan-quing,1999. In this case the purpose was to identify the numbers, rather than the
weight of shark.

Discards in the world’s marine fisheries – an update
12
Method 13
but the average weight of the shark is not provided, nor the estimated weight of shark
as a percentage of the total catch. Numbers of fish are often given, but there are no
means of converting the numbers to weight. The lack of characterization of the fleet
or the difficulty in clearly identifying the fleet to which the discard information refers,
creates substantial problems in identifying the corresponding catch/landings by fishery
in the fishery statistics of the country or regional fisheries organization, and in the
subsequent raising of observed discards to the fleet or fishery level.
Time series
Ideally, an analysis of trends in discarding practices should be based on adequate time
series. Selected time series information is presented in Annex A.6 in support of the
conclusions of this report. However, there is a general lack of globally representative
time series on discards. Existing time series are often short as the observer programmes
or the discard studies are often funded as a relatively short-term project rather than as
an integral part of the normative fisheries information collection process. Interpretation
of time series is further complicated by the need for supplementary information (e.g.
changes in regulations, market conditions, catch per unit effort or size of year classes)
needed to determine the reasons for changes in discard rates or in the absolute levels
of discards.
2.4.3 Variability, sampling and raising
Some of the issues raised above are partly a result of the inherent characteristics of
discard information, namely: (i) the high level of variability in discards; and (ii) the
inability to correlate discards with other variables.
Variability
Discards reflect the response of the fisher to the changing circumstances of the fishery.
The quantity of discards depends on an individual fisher’s decision on where and
how to fish, on the results of the fishing activity and on the behaviour and payment
of the crew. Discards will tend to vary16 in relation to catch composition, seasons,
fishing areas, rigging of the fishing gear, market prices, port of landing, duration of
the fishing trip, quota regulations, minimum landing size regulations and many other
factors. Interannual variation may be linked to the presence of strong year classes of
smaller less-marketable fish. Efforts to correlate the volume, composition and temporal
or spatial variability of discards with such parameters have poor or mixed results.
Fishers’ discard behaviour (see Annex D) is characterized more effectively by game
theory than by stable correlations with single, or even multiple parameters. Despite
the high variability inherent in individual discarding actions (e.g. by vessel, trip, trawl
and season), aggregate (summed) discard volumes tend to provide a relatively accurate
estimate of discards.
Sampling
A comprehensive sampling or discard recording programme is required to obtain
an accurate estimate of discards. Such a programme can be carried out by on-board
observers, on board by fishers, through interviews with fishers or through comparison
of landings with a known profile of the total catch. Observer programmes have
consistently been shown to provide the most accurate results, although this is not
necessarily so if discarding is illegal. However, observer programmes may be costly and
may not be appropriate for all types or sizes of vessels. The problems encountered in the
design and uses of discard sampling programmes are further addressed in Annex
C.2.
16 Variability within a fishery (métier) may be greater than between fisheries (Rochet, Péronnet and
Trenkel, 2002).

Discards in the world’s marine fisheries – an update
12
Method 13
Raising
Raising or extrapolating discard estimates obtained from sampling to the level of
the fishery or fleet presents a further set of problems. There are two basic options
available: to raise as a function of effort or to raise as a function of total recorded
catch of the fishery. Effort information is rarely available and catch information often
means recorded landings. Raising discard estimates as a function of single target species
landings data may result in substantial error (Matsuoka, 1997) as discards will tend to
have a weaker correlation with the landings of a single species than with total landings.
Target species landings are likely to be a function of the distribution and availability
of the target species and may not be correlated (van Beek, 1998) with the temporal and
spatial distribution and the size range of the discarded species. Complex models may
also be used for raising, e.g. including information on catch composition, minimum
landing sizes, year classes, seasons or market prices. The raising of discard estimates is
further discussed in Annex C.3.
In this study, total quantities of discards were used if available as such in the cited
literature, i.e. if the author had extrapolated from the fleet sampled to the total fishery.
In these cases, the sample was more commonly raised by landings, and less frequently
raised by effort. In cases where both raising methods were adopted, the mean estimate
of discards was used, unless the author stated a preference. Where the raised discards
quantity was not provided, discards were raised in linear17 proportion to landings, as
the only available raising factor.
2.4.4 Analysis
Analysis and interpretation of the discard database encountered several difficulties that
may result in inconsistencies and potential sources of errors.
Temporal inconsistency
Every effort has been made to use discard and landings information from the 1994
to 2003 period. For a given database record the information on which a discard rate
is estimated and the information on landings for that particular fishery may refer to
different years. Landings quantities and discard quantities from different years were
summed to provide the respective global totals.
National check-sum gaps
The sum of the catches for fisheries where information is available is frequently less
than the total recorded national catch. Assignment of a discard rate to the balance of
the catch is problematic and was not attempted (also see Confidence limits on p. 14).
17 Trenkel and Rochet, 2001. The authors reject the linear relationship between catch and discards for the
French Celtic Sea fishery.
TABLE 1
Generic example of check-sum gap and temporal inconsistency issues
Country X Catch/landings Discards Discard rate
(%)
Fishery 1 – 2000 data 100 10 10
Fishery 2 – 1998 data 200 50 25
Fishery 3 – 2001 data 300 150 50
Subtotal fisheries 1–3 (mixed years) 600 210 26
FAO Fishstat national total 1 000 Not estimated
Balance 400 Not estimated Not estimated

Discards in the world’s marine fisheries – an update
14
Method 15
Estuarine and freshwater species
Freshwater species have been excluded from the FAO Fishstat quantities used in the
study. Catches of freshwater species in marine and estuarine waters are not readily
distinguishable in many catch statistics and may make a significant contribution
to catches and discards in countries with large coastal wetlands and estuaries (e.g.
Bangladesh, Brazil).
Distant water fishing nations
In the discard database, catches of distant water fishing nations were generally assigned
to the coastal state where the fishing takes place. Alternatively, distant water catches
were assigned to the flag state. The assignment is dependent on the information
available with regard to the fishery or fleet. For example, with respect to a coastal state
that has issued fishing licences to a distant water fleet, the name given to the fishery
indicates the distant water nature of the fishery, e.g. country: Senegal; name of fishery:
EU deepwater shrimp trawl.
Double counting
Double counting may arise as a result of including several records that relate to the
same fishery. This occurs when several different studies quantify the discards in a
particular fishery, possibly using different approaches, or for different time periods. In
general, the most recent value or the value that is (subjectively) judged to be the most
accurate has been chosen. Every effort has been made to avoid double counting in
calculating total global discards and the corresponding total landings by using a single
record for each fishery. Records in which double accounting arises are flagged in the
database. All records containing a discard rate (e.g. a time series) are used to estimate
mean discard rates for different fisheries.
Database bias
The results of literature searches or Internet searches using a keyword such as “discards”
will tend to generate more information on fisheries in which discards are a concern
than on fisheries for which discards are not considered problematic. Thus the records
and fisheries contained in the discard database may be biased in favour of fisheries
with high discards. The inclusion of records of artisanal fisheries with a low assumed
discard rate and the use of the fishery-by-fishery methodology may counterbalance
this potential bias. Large numbers of relatively minor fisheries are included, whereas
the database information is incomplete for some major fisheries. The database is
also biased in favour of fisheries for which documentation exists in English, French,
Portuguese and Spanish since most literature searches were made in these languages.
Internet information and “grey” literature published in other languages, in particular in
Arabic, Russian, Japanese, Korean and Chinese, were not comprehensively accessed.
It is not possible to quantify these potential biases.
Confidence limits
Some of the references for individual records provide confidence limits for discard rates
or discarded quantities. However, these individual record confidence limits cannot be
summed or aggregated across records.
As the sum of the landings in the discard database is equivalent to 94 percent of
the ten-year average Fishstat nominal catch, this “sample” represents a substantial
proportion of the population of the world’s fisheries. As such, measures of sampling
error of the weighted mean result in small upper and lower limits. The range of values
for the global estimate is provided (see Annex A.1). The range does not reflect the
internal variance of individual records.

Discards in the world’s marine fisheries – an update
14
Method 15
Indications of the level variance in the discard estimates are provided for the major
types of fisheries (e.g. shrimp trawl, finfish trawl) as standard deviations from the mean
discard rate for each of these groups of fisheries (Annex A.2).
Narrow confidence limits are required for stock assessments in some jurisdictions,
for example by the EC. The observer coverage required to achieve similar confidence
limits for discards may incur substantial costs.
Survival of discards
This study does not address the survival of discards, which has been studied in many
fisheries. Among the factors influencing the survival of discards are the depth of
fishing, duration of trawls, soak time for lines and nets, and the physiology of the
species discarded. In comparison with fish escaping from trawls, those fish escaping
from traps tend to have a high survival rate as do releases of live lobster and crab.
Impact of discards
An associated FAO study (Poseidon Aquatic Resource Management Ltd, 2003) has
examined aspects of the economic and ecological impacts of discards. These impacts
are difficult to distinguish and isolate from the impacts of bycatch and fishing activities.
The ecological and economic issues are briefly discussed in Sections 4.5 and 4.6.3
respectively.
Interpretation
The global discard estimate provided in the results section may be misinterpreted, no
matter how carefully predicated by caveats. As previously indicated, the records in the
database may be biased in favour of a high estimate of discards. The database remains
incomplete and discard information on several important fish-producing countries has
not as yet been compiled, or is only partially compiled. These countries include the
Democratic Republic of Korea, the Republic of Korea and the Russian Federation. The
omission of some important fisheries may in itself be a source of bias. Assumptions
regarding discard rates applied to certain fisheries will require further verification.
Discard estimates may be politically sensitive and imprecise discard estimates can lead
to political and other difficulties.18 As such, these results must be treated with due
caution and interpreted in the appropriate context.
2.4.5 Future updating of the discard estimate
Discard practices may change rapidly as a result of changes in fish stocks, in regulations,
in markets, or in any of the multiple factors influencing the behaviour of fishers. The
estimates should therefore be repeated at intervals in order to monitor trends in
discarding practices and the implementation of the relevant parts of the CCRF.
FAO plans to update the discard estimates periodically from national sources and
through regional fisheries organizations. The country-by-country architecture of
the discard database and the references associated with each record enable updating,
verification, substitution or addition of records by competent experts from each FAO
statistical area.
18 For example, the Pacific Fisheries Management Council (PFMC) in the United States has been forced
to reassess bycatch and discard rate assumptions under a ruling by the federal magistrate in Natural
Resources Defense Council, 2001.

17
3. Results
3.1 OVERVIEW OF RESULTS
3.1.1 Estimated discards
Based on the set of complete records in the discard database, the sum of the recorded
discards is 6.8 million tonnes for total recorded landings of 78.4 million tonnes
(Table 2). The global weighted discard rate is 8 percent.
Global quantity of discards
Applying the weighted average discard rate (8 percent) to a ten-year average of the FAO
Fishstat19 reported global nominal catches gives a total discards estimate of 7.3 million
tonnes (Table 2). If this extrapolated quantity of global discards is added to the nominal
catch, the total global marine catch (= gross catch) is approximately 91 million tonnes,
excluding the unknown quantities harvested by illegal and/or unrecorded fishing.
Comparison with previous estimates
Because of the different methods of calculation, the estimate of 7.3 million tonnes
provided in this study is not directly comparable with the 1994 global discard estimate
of 27 million tonnes. Nevertheless, the estimate is less than 50 percent of the lower
end of the 1994 range (17.9 million tonnes). Even allowing for some overestimation in
the Alverson assessment and some underestimation in the present study, the current
estimate strongly suggests a reduction in discards and discard rates at the global level.
The evolution of the different global estimates of discards is discussed in detail in
Annex B. The 1994 estimate is based on data from the 1980 to 1992 period while, with
some exceptions, the current study has used data from the 1992 to 2003 period.
Reduction in global discards
Time series at the global level are not available to provide comprehensive empirical
evidence of reductions. However, there is compelling evidence for a substantial reduction
in discards based on an examination of trends in many major fisheries. A summary of
the considerations leading to such a conclusion is given in Sections 3.1.2 and 3.1.3.
Supplementary tables (see Annex A.6, Table 27) provide supporting information on
discard reduction in selected fisheries, many of which make major contributions to the
global discard total. The reduction can be attributed to two major factors:
• a reduction in bycatch resulting from the use of more selective fishing gears,
the introduction of bycatch and discard regulations, improved enforcement of
regulatory measures and reduction of effort in some major trawl fisheries; and
TABLE 2
Estimate of the annual global quantity of discards (tonnes)
Summed landings for which discard information was available178 448 399
FAO average marine nominal catch for 1992–2001 period (from Fishstat) 83 805 355
Weighted discard rate 8%
Total estimated discards (from discard database) 6 824 186
Extrapolated global annual discards for 1992–2001 period 7 290 170
1 Equivalent to 94 percent of a ten-year (1992–2001) average of Fishstat nominal catch.
19 Fishstat Plus (version 2.3) of 24 July 2003. The nominal catch value excludes marine animals and plants.

Discards in the world’s marine fisheries – an update
18
Results 19
• increased retention of bycatch for direct utilization as a result of improved
technologies and expanding market opportunities, or for conversion to fishmeal,
silage or similar products, and changes in target species to include species
previously discarded.
Discards by FAO area
Table 4 and Figure 1 (pp. 20–21) present the sum of the recorded discards by FAO
statistical area. The table includes a column derived from FAO Fishstat showing a
ten-year (1992–2001) average reported nominal catch (excluding marine plants, marine
animals and marine mammals) for each FAO statistical area. The Northeast Atlantic
(Area 27) and Northwest Pacific (Area 61) jointly account for 40 percent of estimated
discards, attributable to high discards in many EU fisheries and in some Japanese
fisheries. Details of discards and discarding practices by FAO area and by fishery are
presented in subsequent sections and supplemented by additional tables in Annex A.
Some differences are apparent between the Fishstat nominal catch data and
aggregated country landings, as derived from national statistics and other sources
during this study. However, it is not valid to compare the two data sets directly, since
the landings reported in the discard database are a sample reflecting the availability
of discard information. The differences between the data sets are also a result of the
different time periods used, different sources of data and the summing of different
years in the case of the discard database. A region-by-region commentary is provided
in Section 3.2.
Discards by country
Discards and discard rates by country are tabled in Annex A.4, Table 24. Discards in
low income food deficit countries (LIFDCs) are highlighted, with a view to indicating
where future efforts at discard reduction may be directed.
Discards by fishery
Tables 3 to 6 provide an overview of discards by major type of fishery. Shrimp and
demersal finfish trawl fisheries account for over 50 percent of total estimated discards
while representing approximately 22 percent of total landings. Tropical shrimp trawl
fisheries have the highest discard rate and alone account for more than 27 percent of
total estimated discards. Small-scale fisheries account for at least20 8.5 million tonnes
(11 percent) of the discard database landings and in aggregate have an estimated discard
rate of 3.7 percent.
The discards by fishery are discussed in detail in Section 3.3. Fisheries with the
highest discards and discard rates are tabulated in Annex A.
Approximately 50 percent of discards are accounted for by the 80 percent of records
with the lowest discard rates (Table 6). Conversely, if records are taken as proxies for
fisheries, then 20 percent of the fisheries account for 50 percent of the discards. The
total (cumulative) landings for fisheries with discard rates below 1 and 5 percent are
40.9 million tonnes and 57.6 million tonnes respectively.
Because of lack of information on the state of the individual fisheries (e.g. under-
/overexploited), it has not been possible to examine discard rates in relation to the level
of exploitation. The use of the term “overexploited” often refers to a particular target
fish stock, rather than to a fishery, which may target a number of species.
20 There are considerable difficulties in disaggregating catches between industrial and small-scale fisheries.
The percentage cited above (11 percent) does not indicate the proportion of the global catch harvested in
small-scale fisheries.

Discards in the world’s marine fisheries – an update
18
Results 19
TABLE 3
Summary of discards by major types of fishery (tonnes)
Fishery Landings Discards1
Weighted
average discard
rate
(%)
Range of
discard rates
(%)
Shrimp trawl 1 126 267 1 865 064 62.3 0–96
Demersal finfish trawl 16 050 978 1 704 107 9.6 0.5–83
Tuna and HMS longline 1 403 591 560 481 28.5 0–40
Midwater (pelagic) trawl 4 133 203 147 126 3.4 0–56
Tuna purse seine 2 673 378 144 152 5.1 0.4–10
Multigear and multispecies 6 023 146 85 436 1.4 n.a.
Mobile trap/pot 240 551 72 472 23.2 0–61
Dredge 165 660 65 373 28.3 9–60
Small pelagics purse seine 3 882 885 48 852 1.2 0–27
Demersal longline 581 560 47 257 7.5 0.5–57
Gillnet (surface/bottom/trammel)23 350 299 29 004 0.5 0–66
Handline 155 211 3 149 2.0 0–7
Tuna pole and line 818 505 3 121 0.4 0–1
Hand collection 1 134 432 1 671 0.1 0–1
Squid jig 960 432 1 601 0.1 0–1
1 The sum of the discards presented in this table is less than the global estimate, as a number of discard database
records could not be assigned to particular fisheries.
2 Low estimates in some fisheries (e.g. gillnet) are partly a result of the inclusion of high Chinese catches with low
or negligible discard rates.
Source: discard database.
TABLE 5
Fisheries and fishing areas with very low to negligible discard rates
Net fisheries
Midwater trawl for small pelagics
Beach-seine fisheries (developing countries)
Purse seines for small pelagics
Saury stick-held dipnet (Japan)
Line fisheries
Handline fisheries
Trolling for large pelagics
Tuna pole and line
Squid jig fisheries
Trap and other fisheries
Fixed fish trap fisheries
Pot fisheries (excepting discards of berried female/undersized crabs and lobsters)
Diver and collection fisheries
Small-scale and artisanal fisheries in general
Areas
Southeast and East Asian fisheries in general
South Pacific Islands coastal fisheries (multigear/multispecies)
Caribbean Islands coastal fisheries (multigear/multispecies)
Fisheries in countries with a “no-discards” policy
TABLE 6
Breakdown of discard rates by quintile of total quantity of discards
Cumulative percentage of total discards 20% 40% 60% 80% 100%
Percentage of records 72% 8% 6% 7% 7%
Range of discard rates 0–13.8% 14–27.1% 27.3–40% 41.2–61.3% 61.6–96%
Cumulative discards (tonnes) 1 364 251 2 569 061 4 016 954 5 452 227 6 824 186
Cumulative landings (tonnes) 65 863 626 73 527 837 76 773 955 78 062 224 78 432 299
Note: the breakdown was derived from sorting records by (i) discard rate as a primary sort key; and (ii) by quantity of landings as a
secondary key.
Source: discard database.

Discards in the world’s marine fisheries – an update
20
Results 21
FIGURE 1
Recorded discards by FAO statistical area
*Note: the high discard rate in FAO Area 81 is a data artefact (see area discussion)

Discards in the world’s marine fisheries – an update
20
Results 21
TABLE 4
Summary of recorded discards by FAO statistical area (tonnes)
FAO statistical area/other grouping/
item
Data source: discard database Data source: FAO Fishstat
Indicative
coverage2
(%)
FAO statistical area(s) Discards Associated
landings1
Discard rate
(%) FAO statistical area(s) 1992–2001 mean
nominal catch
Arctic Sea 18 0 0 – 18 n.a.
Atlantic, Northwest 21 92 926 909 142 9.3 21 2 123 792 43
Atlantic, Northeast 27 1 332 212 8 921 013 13.0 27 10 799 785 83
Atlantic, Western Central 31 831 808 1 372 480 37.7 31 1 687 236 81
Atlantic, Eastern Central 34 309 718 2 631 660 10.5 34 3 118 038 84
Mediterranean and Black Sea 37 17 954 352 228 4.9 37 1 449 955 24
Atlantic, Southwest 41 193 668 1 413 682 12.0 41 2 301 953 61
Atlantic, Southeast 47 95 896 1 626 692 5.6 47 1 560 103 104
Indian Ocean, Western 51 205 428 2 931 174 6.5 51 3 026 425 97
Indian Ocean, Eastern 57 151 190 4 205 810 3.5 57 3 938 277 107
Pacific, Northwest 61 1 355 822 22 052 304 5.8 61 21 896 194 101
Pacific, Northeast 67 192 829 2 078 367 8.5 67 2 898 518 72
Pacific, Western Central 71 407 826 9 366 816 4.2 7137 136 017 131
Pacific, Eastern Central 77 167 351 700 623 19.3 77 1 107 429 63
Pacific, Southwest 81435 475 38 760 47.8 81 748 093 5
Pacific, Southeast 87 530 582 14 675 997 3.5 87 14 648 906 100
Multiple area5 (Central America) 31, 77 27 335 12 557 68.5 – – –
Multiple area 67, 77 150 161 287 937 34.3 – – –
Multiple area 71, 77 2 138 13 362 13.8 – – –
Subtotal without Antarctic and tunas 6 102 399 73 604 939 7.7 78 440 723 94
Tunas, bonitos, billfish
Atlantic and Mediterranean ICCAT (21, 27, 31, 34, 41, 47,48) 156 930 823 962 16.0 21, 27, 31, 34, 37, 41, 47, 48 684 080 120
Indian Ocean IOTC (51, 57) 139 465 1 409 589 9.0 51, 57 1 214 669 116
Pacific, E. Central IATTC (67, 77, 87) 56 508 672 968 7.7 77 401 753 –
Pacific, SW and W. Central SPC (71, 81) 162 068 1 919 706 7.8 71, 81 1 916 653 –
Pacific, NE, NW, SE 61, 67, 87 1 013 337 –
Subtotal tuna 514 972 4 826 225 9.6 5 230 492 92
Antarctic
Atlantic, Antarctic n.a. n.a. – 48 124 846 0
Indian Ocean, Antarctic n.a. n.a. – 58 8 883 0
Pacific, Antarctic n.a. n.a. – 88 411 0
Subtotal Antarctic CCAMLR (48, 58, 88) 2 079 14 336 12.7 134 140 11
Global shark fin (derived from) Global 206 815 17 235 92.3 – –
Total for sample 6 824 186 78 448 399 8.0 All FAO areas 83 805 355694
1 Catches/landings as recorded by the study from national statistics and other sources (see methodology).
2 The column “Indicative coverage” gives “study landings as a percentage of the Fishstat average nominal catch (1992–2001)”. It is provided only as an indication of relative coverage by the study. The 94
percent value does not mean that 94 percent of global landings have been accounted for in the study, but merely illustrates that a high proportion of the world’s fisheries have been considered. This column
is primarily intended to indicate relatively low adequate coverage in certain FAO statistical areas (e.g. Areas 81and 21).
3 It
is not valid to compare the two data sets directly. The large difference between the discard database and Fishstat values shown for Area 71 is largely attributable to Viet Nam (a 2.2 million tonne difference
between the historical average and recent reported catches). Note that Fishstat assigns over 90 percent of the Chinese nominal catch to Area 61 and assigns 100 percent of Viet Nam’s nominal catch to Area 71.
4 The high discard rate in Area 81 is a data artefact resulting from the relatively low number of database records for that area.
5 The study was unable to separate recorded catches for some countries by FAO statistical area. These catches are recorded as “multiple area”.
6 Sum of areas, not average of global values by area. Quantities exclude aquatic plants and animals and fish considered to be freshwater species.
Source: Discard database and Fishstat Plus version 2.3 (2003).

Discards in the world’s marine fisheries – an update
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Results 23
3.1.2 Bycatch reduction
Several major fisheries and numerous smaller fisheries, which previously made
significant contributions to the global volume of discards, have introduced more
selective fishing gears, reduced fishing effort or applied other measures that have
reduced unwanted bycatch. Examples of major fisheries in which bycatch has been
significantly reduced include:
•
United States Northwest Pacific groundfish fisheries, in particular those under the
management of the North Pacific Fisheries Management Council (NPFMC). A
variety of measures are used including area and seasonal closures, bycatch quotas and
total allowable quotas (TACs), and economic measures (see Annex A.6.1);
• United States Gulf of Mexico and Atlantic shrimp trawl fisheries where bycatch
reduction devices and turtle excluder devices (TEDs) are obligatory in certain
areas;
• Argentina’s hake and other trawl fisheries operating in areas where juvenile hake
are caught;
• numerous Canadian and Northwest Atlantic Fisheries Organization (NAFO)
fisheries as a result of a range of management measures, changes in target species
and reduced trawl effort;
• the Arafura Sea shrimp trawl fishery where BRDs have been introduced (although
enforcement of BRD regulations is reported to be problematic);
• the Gulf of Carpentaria northern prawn fishery and other Australian trawl
fisheries;
• EU Nephrops fisheries in which square mesh panels are obligatory;
• EU flatfish fisheries where the minimum landing size (MLS) has been decreased
for some species; and
• fisheries in countries with “no-discard” policies (e.g. Norway and Iceland).
Many factors have contributed to bycatch reduction. United Nations resolutions on
bycatch and discards (see Section 4.2.1) and promotion of the CCRF have increased
public and international awareness of discards as morally unacceptable waste. Scientific
concerns over the unaccounted mortalities of juvenile fish, and fishers’ concerns21
over the impact of unsustainable fishing practices on ever-scarcer fish resources have
resulted in a broad range of bycatch and discard reduction initiatives. Economic factors
such as the costs of sorting catches, crew shortages, efforts to comply with ecolabelling
requirements, and the introduction of quotas on bycatch species have all contributed
to reductions in unwanted bycatch. Improvements in fisheries management in general,
changes in fisheries regulations and improved enforcement of regulations have also
played an important role in bycatch reduction. In several countries, the common
concerns of government and industry have enabled the formulation of joint bycatch
reduction strategies and implementation of mutually agreed measures. National efforts
to reduce bycatch and discards have been complemented by important contributions
from non-governmental organizations (NGOs) and the media in raising public
awareness and concern over wastage in fisheries. Changes in target species and a
decrease in the level of trawl effort in several important fisheries have also played a
role in discard reduction.
However, some fisheries have contributed to increases in discards, notably the
expanding deepwater fisheries and fisheries where severe quota restrictions have
resulted in highgrading. Overfishing in many fisheries also contributes to increases in
discards, particularly where an increasing proportion of the target species is comprised
of juveniles or fish below the MLS. Nevertheless, overfishing may also result in discard
reduction when fishing effort or catches decline, or when prices for previously discarded
fish increase. Anecdotal evidence suggests that despite the introduction of square
21 For example, see Wray, 1995. The fishing industry made substantial contributions to this initiative.

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Results 23
mesh panels and other bycatch reduction measures in the EU, stricter enforcement of
progressively reducing quotas is resulting in greater discards in some fisheries.
3.1.3 Increased bycatch retention and utilization
Many species and types of fish that were previously considered to be bycatch are now
included in a broader range of target species. It is not clear to what extent increases in
global marine captures may be a result of increased landings of previously discarded
species. Lack of time series again precludes empirical assessment at the global level,
but evidence strongly suggests increased utilization of bycatch in many fisheries,
particularly in:
• South Asian and Southeast Asian fisheries, which (with some exceptions) have
very low or negligible discard rates. The increased utilization is partly a result of
increased demand for aquaculture feed and innovations in product development;
•
African industrial trawl fisheries, which are marketing increasing quantities of
previously discarded demersal finfish, particularly on African22 urban markets; and
• increased at-sea processing by factory vessels producing surimi23 and related
products. However, these operations may result in increased disposal of offal and
processing waste, which are not considered discards.
Several related reasons for increased bycatch utilization can be identified:
• population and income increases leading to greater demand and price increases for
fish products, particularly in developing countries;
• use of low-value bycatch for aquaculture and animal feed, particularly in South
and Southeast Asia;
• development and transfer of technologies to use small-sized fish of a variety of
species to produce value-added products, such as surimi;
• development of consumer markets for unfamiliar or previously discarded species,
e.g. deepwater shark, and reduced availability and increased prices of preferred
species;
• reductions in quotas or target species catches (possibly caused by overfishing),
which frees hold space for increased retention of non-quota species or lower
valued bycatch;
• shorter fishing trips to improve fish quality, but which may also create “spare”
hold capacity that can be used for bycatch;
• increased at-sea collection of bycatch, particularly in tropical shrimp trawl
fisheries in Africa and in Central and South America;
• changes in management regimes that encourage, facilitate or even oblige landings
or at-sea collection of bycatch;
• other changes in regulations, e.g. a reduction in the MLS to ensure compatibility
with trawl mesh sizes and the ability to transfer target or bycatch quotas between
vessels or fishers; and
• economic incentives to maximize returns from the catch.
In theory, a reduction in discards should be reflected in the statistical information
on trends in the composition of landings.24 However, because of natural fluctuations
in catch composition, aggregation of catch information at species level (i.e. a large
proportion of the catch is recorded as “not elsewhere included”), the trends in retention
in previously discarded species cannot readily be detected at global level by analysis of
species composition in the Fishstat database. Fishery-by- fishery analysis may provide
a clearer indication of such trends.
22 For example, Senegal now exports more demersal fish to Africa than to Europe.
23 For example, Argentina, Chile, Northeast and Northwest Pacific.
24 If it is assumed that discards are more likely to comprise animals at a lower trophic level, then the
evidence for “fishing down aquatic food webs” can be considered corroborating.

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Results 25
Further efforts to promote bycatch utilization25 are likely to reduce discards further
in LIFDCs, particularly in Africa, Central America and in the fisheries along the north
and east coast of Latin America.
The following sections are presented as illustrative of general trends but disguise the
wide variety of discarding practices, the reasons for discarding and the ongoing changes
in the fisheries concerned.
3.2 DISCARDS IN SELECTED REGIONS AND COUNTRIES
This section provides a brief commentary on discards in selected regions and countries.
The groupings do not precisely correspond to FAO statistical areas since the marine
waters of some countries may extend to more than one FAO statistical area. The
commentary concentrates on major fisheries, points of interest and trends. Only
selected sources are cited.
3.2.1 Northeast Atlantic (Area 27)
Two groups of countries can be distinguished in Area 27. Norway, Iceland and the
Faeroe Islands pursue a “no-discards” policy; all other countries permit discards, while
promoting selective fishing and increased utilization of the catch. The no-discards
policy is further discussed in Section 4.3.1.
Northern waters
Norway has a weighted discard rate of 3.9 percent, or about 100 000 tonnes of discards
from landings of approximately 2.5 million tonnes (Valdemarsson and Nakken, 2002).
The fisheries in the far northern International Council for the Exploration of the
Sea (ICES) areas have relatively low discard rates, partly because of the influence of
Norwegian policy exercised through international fishing agreements and because
of the relatively low diversity in catch composition. The large proportion of pelagic
species in the total catch and the high manufacturing capacity for fishmeal in Norway,
Denmark and Iceland also contribute to a low aggregate discard rate.
Baltic Sea
A relatively small number of commercial species in the Baltic (cod, herring, sprat,
salmon) and a well-developed processing industry combine to ensure relatively low
levels of discards in Baltic fisheries. Cod trawl discards are reported26 to be less than
7 percent, while a discard rate of 5 percent in salmon and cod gillnet fisheries is
primarily a result of seal damage to the catch. The largest fisheries (by quantity) are
the herring and sprat “fishmeal” fisheries that have low or negligible discards. The
aggregate discard rate for the Baltic is estimated (ICES, 2000a) to be 1.4 percent.
North Sea
Pelagic species and species targeted for fishmeal production jointly account for over
70 percent of North Sea landings. These fisheries have low discard rates. Nevertheless,
total annual North Sea discards have been estimated to be between 500 000 tonnes
(comprising 120 000 tonnes of roundfish, 200 000 tonnes of flatfish and 180 000 tonnes
of benthic invertebrates) and 880 000 tonnes (Camphuysen et al.,1995; Tasker et al.,
2000). Since 1981 there has been a tendency for the discard rate to increase (European
Commission, 2002), partly as a result of overfishing and high catches of juveniles,
although recent declines in catch and effort mean that the total quantity of discards
may have decreased in recent years. High interannual variation in the total quantity of
25 For an analysis of the utilization of bycatch and discards see Clucas, 1997.
26 See also Box 6 which gives an example of the difficulties in harmonizing gear (BACOMA trawl) and
MLS regulations in the International Baltic Sea Fishery Commission (IBSFC) area.

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Results 25
North Sea discards is closely related to the magnitude of the year classes of whiting,
haddock and cod.
The Netherlands and Belgian beam trawl fisheries and the Nephrops and Crangon
trawl fisheries account for a substantial proportion of discards. The Netherlands beam
trawl fishery targeting sole in the North Sea has been estimated to discard in the order
of 270 000 tonnes of fish, invertebrates and debris annually.27 North Sea haddock
discards represent 20–50 percent of the total catch of the species (50 000–100 000
tonnes per year). Annual whiting discards are in the order of 50 000 tonnes. The
flatfish beam trawl fisheries have discard rates in the order of 70 percent while the
shrimp (Crangon) and Nephrops beam trawl fisheries have discard rates as high as 83
percent. A reduction of the MLS for plaice in the North Sea has resulted in retention of
increased quantities of juvenile plaice in recent years. Closures of some inshore areas to
trawls (in ICES IVb, c) and the mandatory use of square mesh panels in the Nephrops
trawls have contributed to a significant reduction in discards of juvenile plaice and
whiting and haddock respectively.
EU Atlantic fisheries
There is greater species diversity in waters under the jurisdiction of EU members
than the more northerly European waters. The dominance of demersal trawl gear
and high discards by the important shrimp, Nephrops, and flatfish trawl fisheries are
major factors that contribute to high aggregate discard rates in EU Atlantic fisheries.
Overfishing of demersal stocks is also a primary contributing factor to the high level of
discards in many of these fisheries. MLS and quota regulations, weak market conditions
for smaller-sized fish and a diminishing proportion of larger-sized fish in some fisheries
contribute to regulatory discards and highgrading in EU waters. A lack of definition
of manageable fishery units and the wide geographical range of many important stocks
throughout the waters of several member states mitigate against the formulation of
bycatch and discard management plans.
Discards are rarely estimated on a systematic and continual basis in most EU
fisheries and as EC fisheries legislation28 does not require mandatory recording
of discards, most of the studies are based on limited29 seagoing observer coverage.
Numerous EC studies on discards have tended to focus on those of commercial target
species. However, discard estimates are generally not included in stock assessments.30
This is a result of several factors,31 including the low level of observer coverage, which
may not meet the requirements of a statistically significant sampling protocol, and the
concern that inclusion of the lower quality of discard data would simply detract from
the (higher) quality of the catch and other data used in stock assessments.
High discard rates were identified in a broad range of EU fisheries, including deepsea
fisheries; the Algarve Nephrops and deepwater shrimp trawl fishery (70 percent); the
Algarve demersal finfish trawl fishery targeting hake, seabream and other species
27
van Beek, 1998. The data are from 1976 to 1990, but substantiated by more recent additional information.
28 EC Regulation 1639/2001 specifies a triennial collection of discard data for some stocks, which may
not be useful in stock assessment. If discard data are used for recruitment indices then an estimation of
discarding levels is required annually.
29 The EC observer programme under Regulation 1639/2001 for the year 2002 planned to field only 34
observers, including Icelandic participation in the programme (ICES, 2002).
30 While the exclusion of discard estimates from stock assessments may not significantly affect the
assessment per se, its inclusion may influence recruitment projections and management advice. Many
United States fishery stock assessments include discard estimates. The IBSFC/ICES assessments include
discard estimates as does the stock assessment for North Sea haddock and northern hake. Breen and
Cook (2002) conclude that the exclusion of discard estimates would lead to significant biases in all
aspects of stock assessment.
31 “... the levels of sampling effort currently being applied in European fisheries are not providing adequate
discarding information for stock assessments as currently carried out” (ICES, 2002).

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(62 percent); the Irish razor shell dredge (60 percent); and the French Bay of Biscay
hake trawl (56 percent). Nephrops trawlers have a consistently high level of discards.
A substantial quantity of additional discard information is available from a range
of EC studies32 and as a result of the work of the ICES Study Group on Discard
and By-catch Information (SGDBI), which has coordinated, compiled and analysed
discard information on several EU fisheries.33 Because much of this information
refers exclusively to discards of target species, rather than to total discards, additional
complementary information is required prior to inclusion in the discard database.
Western waters
Increasing pressure on stocks in the area known as the “Western waters” (West of
Ireland and Scotland) by Irish, French, Spanish and United Kingdom fleets has reduced
average sizes of some species with a consequent increase in discards. In 1999, whiting
discards (in the order of 25 000 tonnes, particularly from the Nephrops fisheries)
represented 60 percent by weight of the catch and more than 80 percent of the catch
by number. Approximately 30 percent of Irish hake catches (ICES Areas VI and VII)
are discarded, partly because of trawl damage to the fish and about 25 percent of the
discards are of marketable size. Large quantities of pelagic species (horse mackerel,
mackerel and blue whiting) are discarded by Spanish demersal trawlers because of
weak market demand and quota restrictions.
Quota restrictions increasingly influence highgrading and other discarding decisions
in both demersal and pelagic fisheries, in particular when the catch composition
consistently differs from the quota mix available to fishers, in some cases as a result of
weaknesses in quota trading systems.
Deepwater trawl fisheries off the west coast of Ireland (Rockall Trough, Hatton
Bank) targeting roundnose grenadier, blue ling and orange roughy have high discards
of shark and grenadier. Discard rates vary between 31 and 90 percent depending on the
fleet (French, Irish and Spanish fleets participate), target species and depth range.
Inshore bivalve dredge fisheries for scallop and razor recorded discard rates of 25
and 60 percent respectively, while Irish Sea Nephrops fisheries have similarly high
discard rates to the North Sea fisheries.
Celtic Sea and French Atlantic fisheries
Almost 33 percent of the catch of the French trawler fleet operating in the Celtic
Sea is discarded (Rochet, Péronnet and Trenkel, 2002), a total of 30 000 tonnes (data
from 1997). Total discards by the French fleet fishing in ICES Areas VII and VIII are
estimated (Melnychuk et al., 2001) to be approximately 150 000 tonnes or 18.7 percent
of the total estimated catch (including discards) of over 820 000 tonnes.
Iberian fisheries
Spanish multispecies baca trawls discard 45 percent of the catch (Lart et al., 2002b)
while the Spanish gillnet fisheries, hake longline and small pelagics purse-seine fisheries
have discard rates in the 13–15 percent range. The Algarve34 trawl fisheries discard over
35 000 tonnes, while the seine and encircling net fisheries discard approximately 40 000
tonnes. Particularly high discard rates are reported from the small Tagus estuary beam
32 See ICES, 2000b for an inventory of studies on discards in the ICES area. Some studies address the
economic aspects of discards.
33 The SGDBI reports are available on the ICES Web site (www.ices.dk). See ICES, 2002 for a listing of the
discard data tables by country, ICES area and major species. Additional information is required to make
fishery-by-fishery estimates. Data referring to non-target species have not been compiled for several
studies.
34 See reports of the DISCALG and DISCARDS I projects, e.g. DISCALG 97/0087 Análise das rejeições
da pesca - sul de Portugal.

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Results 27
trawl targeting sole and Crangon (90 percent) and the Algarve Nephrops and deepwater
shrimp fishery (43–70 percent).
3.2.2 Mediterranean and Black Sea (Area 37)
Most of the information on discards in the Mediterranean is a result of a range of EC
studies that focused on deepwater trawl fisheries (mainly targeting shrimp) and pelagic
gillnet fisheries, which have an incidental catch of marine mammals and turtles. The
discard database accounts for only 24 percent of the 1.5 million tonne nominal catch
from the Mediterranean and Black Sea, reflecting a shortage of information on discards
for Area 37. The trawl fisheries discard 20–70 percent of the catch, depending on depth.
Average discard rates for these trawl fisheries are 45–50 percent. Most of the artisanal
fisheries discard less than 15 percent of the catch, although little empirical information
is available. The Mediterranean has relatively few trawl grounds, which contributes to
a relatively low level of discards and a weighted discard rate of 4.9 percent. In many
fisheries there are negligible discards, for example in Syrian trawl and artisanal fisheries
and in many of the North African artisanal fisheries.
Other than for Turkey, no discard information from Black Sea countries was
obtained. The anchovy purse-seine fishery has negligible discards since most fish is
used for fishmeal. Midwater trawlers targeting sprat slip anchovy and other species
(discard rate 5.1 percent). The sea snail dredge fishery has a discard rate of 11.5 percent
while coastal encircling nets have a discard rate of 7.4 percent. Little information on
discards in North African countries is recorded in the discard database,35 although
significant discards may occur in the shrimp trawl fishery of the Gulf of Gabes.
As there are no quota regimes (except for ICCAT species) in the Mediterranean,
highgrading is negligible. There is also a market for small sizes of many species. The
high number and dispersion of landing points makes MLS difficult to enforce and
smaller unmarketable fish may be used either for autoconsumption or bait. Management
measures such as the designation of no-trawl zones (e.g. Sea of Marmara, seagrass beds
and areas of archaeological interest) help reduce discards in the Mediterranean.
3.2.3 North America – Atlantic (Areas 21, 31)
United States
Three important aspects of discards and bycatch management are illustrated in United
States fisheries.36 (The first two issues are addressed in subsequent sections.) These
aspects are:
• the growing impact of the incidental catch of charismatic species in fisheries
management and in trade;
• the emerging influence of civil society with regard to bycatch and incidental catch
issues; and
• the importance of fishery management plans (FMPs).
Fishery management plans
Most federal fisheries operate under FMPs. These are funded management programmes
agreed with stakeholders through regional fishery management councils. As the various
fisheries (multispecies groundfish, halibut, salmon and crab/other crustacean) each
take bycatch species targeted by other fisheries, the economic interests of the various
stakeholders are crosslinked (Queirolo et al., 1995). The Fishery Management Councils
(FMCs), which are charged with preparing management plans, provide a forum to
35 No search of Arabic publications was made and contacts with the relevant fisheries administrations were
not fruitful.
36 Substantial additional progress on bycatch management has recently been made in the United States
while this report was going to press. For details see http://www.nmfs.noaa.gov/bycatch.htm/.

Discards in the world’s marine fisheries – an update
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Results 29
address numerous bycatch and discard issues within the context of the plans. Most of
the information included in the discard database originated from federal sources and
refers mainly to federal fisheries. Discards in fisheries under state jurisdiction are not
well represented.
Several major North American fisheries have a high level of discards. Major
sources of discards include the trawl and dredge fisheries of the Gulf of Maine and
the northeastern United States. These include the silver hake trawl (discard rate 41.7
percent) and Atlantic scallop with important discards of yellowtail flounder. In contrast
to flatfish trawl fisheries in European waters, fisheries for American plaice and witch
flounder have comparatively low discard rates (8.7 and 18.8 percent respectively).
Reductions in discards have occurred as a result of decreased trawl fishing effort and
changes in target species in the area.
In more southerly Atlantic waters, the South Atlantic shrimp trawl fishery discards
over 70 000 tonnes (discard rate 83.3 percent) while the Gulf of Mexico reef fish fishery
has a rate of 44 percent. Discards in clam fisheries are not recorded in the discard
database.
The Gulf of Mexico shrimp trawl fishery shows the highest discards of any single
fishery in the database, discarding an estimated 480 000 tonnes of Sciaenidae, snappers,
emperors and many other species. Numerous changes have occurred that have reduced
bycatch in the fishery (NMFS/NOAA, 1998). TEDs have been obligatory for offshore
vessels since before 1992 and for inshore vessels since 1995. BRDs have been used since
1998 and have been made obligatory west of 83º30’ in 2003. Because of the impact of
the fishery on turtles and juvenile red snapper, major studies have been carried out.
Informed local sources can add significant precision to the discard estimate and trends
for this important fishery.
Mexico
The Gulf of Mexico shrimp fisheries generate 19 000 tonnes of discards (discard rate
46.2 percent) and Pacific shrimp fisheries approximately 114 000 tonnes (discard rate
76.7 percent) (Bojorquez, 1998).
Canada37
The major discards occur in the scallop dredge fishery (23 000 tonnes, 20 percent discard
rate), groundfish trawl (over 11 000 tonnes) and the lobster and crab pot fisheries (over
25 000 tonnes). Minor discards (9 percent) occur in the swordfish longline fishery.
BRDs are used in many NAFO fisheries and NAFO has initiated work on a discard
database. Substantial changes in the Canadian Atlantic fisheries and related regulatory
framework are likely to have resulted in significant reductions in discards in recent
years. As in United States waters the changes include a reduction in trawl effort and
changes in target species from finfish to crustaceans.
3.2.4 North America – Pacific (Areas 67, 77)
Canada
The British Columbia Pacific hake demersal trawl generates discards of arrowtooth
flounder, dogfish and ratfish in the order of 9 000 tonnes (discard rate 8.9 percent). The
shrimp beam trawl fishery has a considerably higher discard rate (29.1 percent) than the
shrimp otter trawl fishery (7.8 percent). Discards in herring and salmon fisheries have
not been recorded in the discard database.
37 Information on Canadian Atlantic fisheries is largely derived from the pre-1996 period (Duthie, 1997b)
and to a lesser extent from more recent NAFO sources. Current studies (R. Forrest, pers. comm.) will
provide more accurate and up-to- date estimates.

Discards in the world’s marine fisheries – an update
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Results 29
United States
The multispecies groundfish trawl fishery of the Pacific states (Washington, Oregon,
California) produces major discards of over 130 000 tonnes with a discard rate of 44
percent (Northwest Fisheries Science Center, 2003). The nearshore shrimp fishery
discards approximately 20 000 tonnes and has a similar discard rate. California’s gillnet
fisheries have substantial incidental catches of common mure, pinnipeds and cetaceans.
The vast majority of dolphins caught in the tuna purse-seine fishery are released alive.
The United States Northwest Pacific (Alaska) fisheries, which previously accounted
for a substantial proportion of global discards, have experienced a significant decline
in discards. Discards in the combined Bering Sea Aleutian Islands/Gulf of Alaska
(BSAI/GOA) groundfish fisheries declined from 307 000 tonnes (14 percent) in 199538
to less than 140 000 tonnes39 (7.3 percent)40 in 2002. Many fish previously discarded are
now the raw material for surimi. In the mid-1990s offal discharges made up almost 60
percent of “total” catch, representing a major energy shunt or transfer in the ecosystem.
In 1995, the crab pot fisheries discarded over 40 000 tonnes (44.1 percent).41 These
discards are mainly regulatory, in response to species quota, minimum size and other
regulations. As already noted, many of the United States non-federal fisheries (i.e.
under state jurisdiction) are not represented in the discard database (or in the United
States Bycatch Matrix) and important scallop, salmon and herring fisheries in Area 67
contribute additional discards that are not recorded in the database.
In these Northwest Pacific fisheries, bycatch limits, area closures and other
prohibited-species bycatch mitigation measures serve to limit discards and total fleet
capacity, and trawl effort has declined. However, some of these measures have also
created barriers to harvesting groundfish total-allowable-catch amounts, and have
generated allocative controversy among harvesters of species taken as bycatch in
the groundfish fisheries. Consequently, comprehensive information on bycatch and
discards is required to prepare management plans for these fisheries, which means that
these fisheries must have a high level of observer coverage (in some cases 100 percent).
In the BSAI/GOA fishery administrators maintain complete records of bycatch and
discards. These records are updated weekly on the Alaska NMFS Web site to ensure
transparency and assist operators in planning their fisheries activities. Fisheries are
closed when bycatch limits are reached. The management of bycatch and discards in
this important fishery is further discussed in Annex A.6.1.
3.2.5 Central and South America (Areas 31, 41, 77, 87)
Central America
The shrimp trawl fisheries in Central America generally have high discard rates.
TEDs are used in most shrimp fisheries in order to comply with United States import
requirements. Government and private sector initiatives to utilize the bycatch have
met with mixed results and could be the subject of a comparative analysis to help
determine effective utilization strategies. Artisanal fisheries and pot fisheries have low
to negligible discard rates.
Caribbean
With the exception of Cuba the shrimp trawl fisheries (e.g. in Haiti and Trinidad and
Tobago) all have high discard rates (70–90 percent in the case of Trinidad and Tobago). In
38 From the United States Bycatch Matrix in Managing the Nation’s Bycatch (NMFS/NOAA, 1998a).
39 NMFS/Alaska Fisheries Weekly Production and Observer Reports to 31 December 2002 indicate total
discards of 138 000 tonnes for 2002 (excluding weights of protected species discards).
40 The discard rate refers to 2001 (Fish Information & Services, 2003). Protected species (crab, salmon)
numbers were converted to weights using average weights obtained from the National Marine
Fisheries Service (NMFS) to give total discards of 148 000 tonnes in 2001.
41 1995 data calculated from the United States Bycatch Matrix (NMFS/NOAA, 1998a).

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Results 31
Cuba the entire catch is landed, either for human consumption or reduction to fishmeal.
The fisheries of the small island states are considered to have zero discard rates.
Northeast South America
The Guianas shelf supports important shrimp trawl fisheries, which have high discard
rates, despite long-standing attention to the bycatch issue (Allsopp, 1982). Artisanal
and industrial shrimp trawler fleets that fish from Venezuela to northern Brazil
targeting penaeid shrimps and seabob (Xiphopenaeus kroyeri) have an average discard
rate in excess of 70 percent. The high discards may be partly attributable to the distance
of the fishing grounds from markets and poor demand for the discarded species. These
fisheries have an aggregate discard of approximately 220 000 tonnes.
Area 41 (Brazil, Uruguay, Argentina and the Falkland Islands [Malvinas])
Trawl fisheries off central and southern Brazil have discard rates in the 22–33 percent
range. Uruguayan trawl fisheries for hake and Corvina have even lower discard rates
(9–18 percent). Argentina’s hake trawl fisheries are a major contributor to global
discards, discarding almost 150 000 tonnes (discard rate 24 percent) in the mid-1990s
(Dato, Villarino and Cañete, 2000). The shrimp beam trawl fishery (discard rate 50
percent) discards substantial quantities of juvenile hake, and the Patagonian scallop
dredge fishery and other clam fisheries are also considered to have high discards. In
contrast, the important squid (jig and trawl) and pelagic fisheries for southern blue
whiting have low discards.
Chile and Peru
Chile harvests an average (1992–2001) of 5 million tonnes of small pelagics, over 330 000
of hake and other demersal finfish and approximately 100 000 tonnes of invertebrates.
Fisheries for small pelagics have a low discard rate and account for under 40 000 tonnes
of discards while the hake fisheries account for approximately 42 000 tonnes of discards
for catches of over 300 000 tonnes (12.5 percent discard rate in the trawl fisheries). Peru
shows a similar pattern of discards, although a higher discard rate in the small pelagic
fisheries (average nominal catch of 8 million tonnes, 1992–2001) generates discards of
260 000 tonnes. The shrimp trawl fishery (discard rate 81 percent) and the hake fishery
also have substantial discards (74 000 and 15 000 tonnes respectively).
3.2.6 Africa and the Red Sea (Areas 34, 47, 51)
The artisanal fisheries are considered to have low or negligible discards unless
information to the contrary is available. The substantial post-harvest losses incurred in
African artisanal fisheries are not included in the discard database.
A high level of observer coverage in the licensed distant water fleets and on national
flag vessels provides a considerable volume of information on discards in industrial
fisheries. A number of countries have 100 percent observer coverage for certain fleets and
Namibia places two observers on certain vessels. The primary focus of these observers,
many of whom have only rudimentary scientific training, is usually on establishing the
quantity and composition of the retained catch. Information on discards is not always
collected, or collected in a systematic manner. Even when available, the information is not
necessarily compiled and analysed. Despite the considerable effort and costs associated
with the observer programmes, observer reports do not tend to be fully exploited, partly
because of staff and funding shortages in the research institutes, or because these reports
are retained by the enforcement agency and not accessed by the researchers.
Area 34 (Morocco to Angola)
Discard rates vary widely. The Moroccan cephalopod trawl fishery discards up to
45 percent of the total catch. The discard rate for the foreign deepwater shrimp fleet

Discards in the world’s marine fisheries – an update
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Results 31
in Mauritania is over 80 percent and 63 percent for a similar fishery in Senegal. An
increasing quantity of finfish bycatch of Senegal’s shallow-water trawl fisheries is being
directed to African urban markets, reducing discards to approximately 34 percent. The
industrial shrimp trawl fishery in Guinea-Bissau discards 87 percent of the catch, while
in neighbouring Guinea the rate is 33 percent, reflecting the relative importance of local
purchasing power and processing capacity with respect to bycatch. Trawlers in Sierra
Leone are obliged to land bycatch for local consumption, which reduces discards.
Trawl fisheries in Ghana, Nigeria and Cameroon have low discard rates since there is
extensive collection at sea. Because of high demand for fish products and high coastal
populations in many areas, discards in the artisanal fisheries are negligible.
Area 47 (Angola to South Africa)
Demersal finfish and shrimp trawl fisheries in Angola are understood to generate
significant discards. Pending legislation will require increased landings of bycatch.
Namibia has a “no-discards” policy that prohibits discarding of marketable fish, i.e.
discards of non-marketable species may be permissible. The hake and monkfish trawl
fisheries have discards in the 5 to 15 percent range. South Africa prohibits discarding
in the hake and sole fisheries and has a progressive bycatch management approach.
Bycatch quotas in the horse mackerel fishery have resulted in pilchard and anchovy
discards in the order of 30 000 tonnes in the past and the hake trawl fishery has a
similar quantity of discards. The south coast trawl fisheries targeting hake, sole and
monkfish have discard rates ranging from 4.1 to 19.2 percent. The highest discard rate
(70 percent) is recorded from the KwaZulu–Natal shallow-water prawn trawl fishery.
Area 51 (East Africa and the Red Sea)
Madagascar’s industrial shrimp trawl fisheries discard over 30 000 tonnes (72 percent
discard rate). Approximately 23 percent of Mozambique’s shrimp trawl bycatch is
landed with over 23 000 tonnes discarded (60 percent discard rate). In the United
Republic of Tanzania’s shrimp fishery, fishing is permitted only during daylight hours.
A discard ban is poorly enforced and about 78 percent of the catch is discarded. A
similar daylight regime has been introduced in Kenya. It is complemented by an inshore
closed area and most previously discarded species are now sea-frozen and landed
for human consumption. No discard information is available for Somalia, although
trawlers fishing close inshore are known to impact on the hard corals. Discards in the
East African artisanal fisheries are negligible. Fisheries in the Comoros, Mauritius and
Seychelles have low to negligible discards.
Discards in most Red Sea artisanal fisheries are also negligible. In Djibouti, even
fish heavily damaged by sharks are retained for sale. Discards in the trawl fisheries
are relatively small as the lower value fish (lizard fish and threadfin bream) find ready
markets in Egypt. Eritrea, which operates a 100 percent observer coverage, calculates
the royalties for the foreign trawl fleet on the value of the total estimated catch, whether
discarded or not. The Egyptian finfish trawlers discard an estimated 20 percent of their
total catch in Eritrean waters.
3.2.7 South and Southeast Asia (Areas 51, 57, 71)
With the exception of the shrimp trawl fisheries, discards in the northern part of Area
51 (Yemen to Pakistan) are low. Aggregate discards from the shrimp fisheries (Saudi
Arabia, Kuwait, the Islamic Republic of Iran, Bahrain and Pakistan) total approximately
100 000 tonnes.
National authorities42 and experts indicate that discards in many countries in South
Asia and Southeast Asia are low or negligible. These countries include Sri Lanka,
42 Pers. comm. with fisheries authorities, 2003.

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India, Myanmar, Thailand, Malaysia, Cambodia and Viet Nam. A recent workshop43on
discards and bycatch identified three factors, which differentiate the fisheries of the
region from most temperate fisheries:
• dominated by small-scale fisheries with most fishing operations lasting less than a
week;
• multispecies nature of the fisheries with fishers depending on many different
species; and
• inherent flexibility of the markets based on a long tradition of consuming a wide
variety of fish and fish products.
The workshop considered that discards for many countries and fisheries in the
region were low or negligible and suggested that rather than endeavouring to obtain
accurate discard estimates at high cost, efforts should concentrate on measures to avoid
catches of juveniles and less marketable species.
Trawl fisheries tend to dominate in the shallow seas of the Southeast Asia region.
In many areas, the fisheries are overexploited and almost all of the catch is landed and
used. The lower value portion of landings that are deemed fit for human consumption
is used for dried fish, surimi, fish balls, fish sauce and a range of traditional and new
fish products. The remainder is used for animal and fish feed. With some notable
exceptions, the fisheries in the region have been assigned a discard rate of 1 percent.
India
Shrimp freezer trawlers operating offshore from Visakapatnam on the eastern coast
of India had relatively high discards in the early 1990s. However, this fleet has almost
disappeared and current discards are low or negligible. Discards are considered to be
negligible in traditional fisheries and very low in motorized fisheries. The reasons for
the decline in discards are similar to many other countries in South and Southeast
Asia:
• overfishing, particularly in inshore and coastal waters;
• rising demand as a result of population increase, rising urban incomes and export
of better quality fish;
• poverty leading to consumption of lower value food fish;
• product development, e.g. production of surimi44 and fish sauce; and
• increased production of fishmeal and animal and fish feed.
Bangladesh and Myanmar
Discard rates in the order of 80 percent lead to discards of over 50 000 tonnes in
Bangladesh’s industrial shrimp and finfish trawl fisheries while estuarine pushnets
collecting penaeid larvae discard 90 percent of the catch. Myanmar’s trawl fisheries
discard approximately 20 000 tonnes. Increasing quantities of fish are being exported
overland from Myanmar to feed the growing demand in southeastern China. Any
move towards intensive shrimp aquaculture in Myanmar is likely to reduce discards
further.
Indonesia
With the notable exception of the Arafura Sea shrimp trawl fishery most Southeast
Asian fisheries have been accorded a discard rate of 1 percent. While some discarding
undoubtedly takes place, the volumes are so low as to be considered insignificant
43 International Workshop on the Estimation of Discards and Measures to Reduce Bycatch in the Indian
Ocean and Western Pacific, Samut Prakan, Thailand, 2003. Global Environment Facility (GEF)/FAO/
Southeast Asian Fisheries Development Centre (SEAFDEC) (unpublished internal FAO report). The
workshop was held under the auspices of the GEF shrimp bycatch project (FAO, 2003a).
44 Improvement in technology is enabling surimi production from shrimp bycatch (IMPEDA [India
Commerce Authority]), pers. comm.

Discards in the world’s marine fisheries – an update
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by most experts from the region. The Arafura Sea shrimp trawl fishery discards
over 80 percent of the total catch, in the order of 230 000 tonnes per year (National
Committee for Reducing the Impact of Tropical Shrimp Trawling in the Arafura Sea,
2001). Despite the introduction of BRDs total discards remain high; a consequence
of weak enforcement of regulations and lack of local markets for the bycatch, since
the fishery is prosecuted at considerable distance from major population centres.
Approximately 76 percent of Indonesia’s nominal catch originates from Area 71.
Gulf of Thailand countries and Viet Nam
An arbitrary discard rate of 1 percent was assigned to the fisheries of Thailand,
Malaysia and Cambodia, which are considered to generate combined discards of under
50 000 tonnes. Similarly, the fisheries of Viet Nam are considered to have insignificant
discards. Recent (internal) estimates of the country’s marine catch are substantially in
excess of Fishstat values. Fishstat assigns all Vietnamese catches to Area 71 although
the Area 71/Area 61 boundary bisects Viet Nam.
Philippines and the South China Sea
Philippine inshore shrimp and finfish trawl fisheries have high discard rates. Industrial
and “baby” trawl fisheries in Sorsogon and San Miguel bays have discard rates ranging
from 19 to 85 percent. In the case of the San Miguel Bay fisheries, 91 percent of the
discards are jellyfish. Trawl fisheries in Brunei Darussalam discard 74 percent of the
catch, reflecting the greater purchasing power of the population and the lack of markets
for lower valued species.
3.2.8 East Asia and the Northwest Pacific (Area 61)
China
Discards are low or negligible in almost all Chinese fisheries.45 Essentially there are no
bycatch species since all species are target species. Some discarding is known to occur in
trawl fisheries which are prosecuted at considerable distance from the port of landing,
e.g. Chinese trawlers operating in the South China Sea. However, discard rates are
considered to be relatively low and no quantitative information was located during the
study. Closed seasons are in force to reduce catches of juveniles in certain fisheries. No
information has been obtained on discards in Taiwan Province of China. Fishstat data
indicate that 98 percent of Chinese nominal catches originate from Area 61. The low
to negligible discard rate in Chinese fisheries, which produce approximately 12 million
tonnes, or over 14 percent of the global nominal catch (average 1992–2001), tends to
skew the global discard rate downwards.
Japan
Landings of over 6 million tonnes generate discards of more than 0.9 million tonnes,
an average discard rate of 14.2 percent. Fisheries with high discards include a diverse
group of small coastal trawlers, the boat-seine fishery (including gochi-ami), and tuna
longline fisheries. Estimates prepared for the 1996 workshop (Matsuoka, 1997) were
transferred unchanged to the discard database. Although it is acknowledged that some
changes have occurred in these fisheries since the estimates were made, changes in the
fishery-by-fishery breakdown of Japanese catch statistics preclude direct transposition
to the most recent Japanese catch statistics.46
No information has been located on discards in the Democratic Republic of Korea
and the Republic of Korea. Because of the severe food deficits in the former country
discards are assumed to be negligible.
45 Ministry of Agriculture, pers. comm. (November 2003).
46 The best available information is that in FAO Fisheries Report No. 547. Matsuoka, pers. comm., 2003.

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Russian Far East
Characterization of fisheries in the Russian Far East has been based on a combination
of sources and in particular the information relating to quota allocation and use
provided by the Russian Federal Research Institute of Fisheries and Oceanography
(VNIRO) and that reported in Russian trade publications.47 Information on discards
in the fisheries of the Russian Far East has proved particularly difficult to obtain and
no estimates are included in the discard database. VNIRO48 has not collected discard
information since the disintegration of the Soviet Union. Regulations on discards are
reported to be poorly enforced. The newer generation of processor trawlers makes full
use of catches, but filleting machinery on older smaller trawlers in the Alaska pollock
fishery is not fully adapted to handle smaller Alaska pollock and discards may be over
45 percent in some parts of the fishery (Norinov, 2003). Catches of Alaska pollock have
declined progressively from over 2 million tonnes in the mid-1990s to under 1 million
tonnes in 2002. The other important components of the catch include Pacific herring,
flounder, Pacific cod, squid and crab. Current discards in the Russian Far East fisheries
may be similar to those in the Eastern Bering Sea in the mid-1990s, which would mean
that approximately 200 000 tonnes might be discarded.
3.2.9 Oceania and Australia (Areas 57, 71, 77, 81)
Pacific Islands
Discard levels are considered to be insignificant in this region. The South Pacific
islands’ coastal commercial, subsistence and artisanal fisheries were allocated49 a discard
rate of 0.5 percent. Discarded species include puffer fish, porcupine fish, “ciguatera”
fish50 and sea snakes. The pole and line fleets may discard small quantities of baitfish,
rainbow runner and similar non-tuna species. A shrimp trawl fishery in the Gulf of
Papua (Papua New Guinea) has substantial discards.
Australia
Most of the larger “offshore” fisheries are managed by the Australian Commonwealth,
while most of the coastal and inshore fisheries fall under the jurisdiction of the Australian
states or territories. Progressive Commonwealth bycatch management policy and
programmes make the Australian fisheries of particular interest (Australian Fisheries
Management Authority, 2000). The overarching objective of the policy is to ensure
that bycatch species and populations are maintained and that fisheries are ecologically
sustainable through bycatch reduction, improved protection of vulnerable/threatened
species and minimizing adverse impacts of fishing on the marine environment.
Bycatch action plans51 have been completed for the following fisheries managed by
the Australian Fisheries Management Authority:
• Australia’s tuna and billfish
fisheries
• Bass Strait central zone
scallop fishery
• Great Australian Bight
trawl fishery
• Northern prawn fishery
• Southeast non-trawl fishery
• Southeast trawl fishery
• Southern shark fishery
• Southern squid jig fishery
• Sub-Antarctic fisheries (Macquarie Island
fishery and Heard Island and McDonald
Islands fishery)
• Torres Strait prawn fishery
47 See Russian Fisheries Report, 2003; Vaisman, 2002; and documents relating to the Convention on the
Conservation and Management of Pollock Resources of the Central Bering Sea.
48 Director of VNIRO, pers. comm. (2003).
49 Based on authors’ experience; Adams (SPC), Gillett (Fiji) and Wright (South Pacific Regional
Environment Programme [SPREP]), pers. comm.
50 Fishing in areas known for “ciguatera” is usually either prohibited or avoided in the South Pacific, the
Caribbean and parts of the Indian Ocean.
51 See http://www.afma.gov.au/.

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These action plans are of particular interest in relation to TEDs, BRDs and mitigation
measures for seabirds in longline fisheries and are further discussed in Section 4.4.1.
Environmental impact assessments are also required in Australia for fisheries from
which products are exported.
Three northern shrimp fisheries, northern prawn (Gulf of Carpentaria), Torres
Strait and Queensland trawl fisheries jointly discard approximately 80 000 tonnes.
The southeast trawl fisheries targeting redfish, tiger flathead, orange roughy and blue
grenadier discard approximately 17 000 tonnes with discard rates of 45 and 10 percent
for the east and west fisheries respectively. The New South Wales (NSW) oceanic
prawn has a high discard rate (88.7 percent) generating approximately 16 000 tonnes of
discards. Experiments have demonstrated that the use of BRDs results in a reduction of
up to 90 percent in unwanted bycatch in the NSW prawn fisheries and that square mesh
panels can be selective for larger prawns (Broadhurst, 2003). BRDs are now mandatory
in inshore/estuarine prawn fisheries. Progressive implementation of bycatch action
plans is likely to reduce the discards and discard rates presented above. Several smaller
fisheries also have high discard rates, e.g. NSW beach seine (58 percent) and the NSW
ocean haul (38 percent).
Discards in New Zealand fisheries have not been recorded in the discard database.
3.2.10 Antarctic and the CCAMLR area (Areas 48, 58, 88)
The Commission for the Conservation of Antarctic Marine Living Resources
(CCAMLR) implements an ecosystem-based approach to manage both commercial
fisheries and other living marine resources. While this approach imposes obligations
on members to record bycatch, the records cannot readily be converted to discard rates
by fishery (CCAMLR, 2002a). A major focus of CCAMLR work is the mitigation of
incidental catch and, through observer programmes, the close monitoring of seabird
and marine mammal mortalities (see Section 4.2.3).
Krill fishery
Fisheries operators reportedly avoid areas where there is likely to be a contaminating
catch of fish52 and large krill aggregations tend to be monospecific (Nicol and Endo,
1997; Sobrino Yraola, Giráldez Navas and Millán Merello, 1987). Vessels also move to
avoid concentrations of salps (pelagic tunicates). Discard information is being collected
by CCAMLR.
Toothfish fishery
The toothfish longline fishery generates the vast majority of the 2 000 tonnes of
discards (discard rate 20 percent). A Chilean experimental pot fishery for toothfish
discards approximately 60 percent of the catch. The discards mainly comprise
crab (P. spinosissima). Discards in the trawl fishery are understood to be low while
mitigation measures are in place to reduce bycatch mortalities of rajids and Macrourus
sp. that comprise approximately 20 percent of the longline catch. A German trawl
survey (Kock et al., 2002)53 around Elephant Island demonstrated that changes in trawl
rigging resulted in a sixfold reduction in bycatch of benthos without affecting the catch
rate of the commercial species.
3.3 DISCARDS IN SELECTED FISHERIES
The fisheries have been grouped and analysed by gear type and target species. There
is very great diversity within a group and considerable caution must be exercised
52 Research cruises of the FV Niitaka Maru found fish bycatch in 41 out of 103 trawl catches. Predominant
species were Lepidonotothen larseni, Pleuragramma antarcticum and Champsocephalus gunnari . There
was a negative correlation between bycatch of fish and the krill catch per unit effort (CPUE).
53 Cited in CCAMLR, 2002a.

Discards in the world’s marine fisheries – an update
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in generalizing discard rates by fishery. For example, in some tropical shrimp trawl
fisheries the use of TEDs and BRDs is strictly enforced, while in others fishing is only
permitted during daylight hours, and many fisheries that target shrimp also target other
finfish or cephalopods. This diversity is shown by presenting both average discard rates
and the respective standard deviations for the subsets of discard database records, for
which the discard rate is available.54 The weighted (pooled) discard rate better reflects
the quantitative importance of discards in such types of fisheries at a global level. Thus
both average and weighted discard rates are presented for many fisheries.
3.3.1 Shrimp trawl fisheries
The discard database indicates that shrimp trawl fisheries, and tropical shrimp fisheries
in particular, are the single greatest source of discards, accounting for 27.3 percent (1.86
million tonnes) of estimated total discards (see Table 8). The aggregate or weighted
discard rate for all shrimp trawl fisheries is 62.3 percent.55 These fisheries56 have
consistently high discard rates deriving from a range of factors.
• Shrimp is often less than 20 percent of the demersal biomass on many shrimp
fishing grounds.
• The relatively small mesh size required to capture shrimp inevitably results in
large quantities of bycatch.
• Vessels are designed for shrimp retention and have limited freezing and hold
capacity for bycatch.
• Transhipment at sea is often discouraged by vessel owners or prohibited by
authorities because of concerns about theft, or illegal/unrecorded transhipment.
• The shrimp grounds are often at a considerable distance from the markets for
bycatch, rendering its retention and transport to market uneconomical.
• Bycatch species are often of small size and their relatively low value makes bycatch
retention uneconomical.
• Enforcement of regulations on minimum landings of bycatch and on discard
reduction may be deficient.
The global average (1992–2001) annual nominal catch of shrimp is 2.5 million
tonnes (excluding Nephrops and other “langoustine”), of which the penaeid shrimp
catch is over 1 million tonnes, the vast majority being harvested by trawlers. However,
increases in the global nominal catch of shrimp in
recent years to approximately 3 million tonnes
means that the total quantity of discards may have
increased by 10 to15 percent.
Tropical shallow water shrimp fisheries
These fisheries57 account for 70 percent of total
estimated discards from shrimp trawl fisheries.
Almost all of these fisheries target penaeid
shrimps. They have an average discard rate of
55.8 percent, but the standard deviation of 0.27
(see Table 8) indicates a relatively wide range of
discard rates. The weighted discard rate of 67.8
percent is substantially higher than the average,
TABLE 7
Frequency distribution of discard rates in shrimp
trawl fisheries
Range of
discard rates
(%)
Number of
records: tropical
industrial shrimp
fisheries
Number
of records:
all shrimp
fisheries
< 20 9 20
20–40 6 13
40–60 10 21
60–80 23 28
> 80 10 15
Total number of
records 58
97
Note: includes five records of semi-industrial shrimp trawl
fisheries. Tropical shrimp refers to penaeid shrimp.
Source: discard database.
54 The corresponding information on catch and discard quantities is not available for all such records.
55 This calculation excludes Chinese fisheries.
56 For a review of bycatch in shrimp fisheries see Andrew and Pepperell, 1992; FAO, 2001a.
57 The average (1992–2001) world catch of penaeids is 1.1 million tonnes (Fishstat Plus, version 2.3).
However, an additional catch of 0.5 million tonnes of “other” shrimps is reported, at least some of
which is penaeid shrimp. Global catches of both tropical and coldwater shrimps have tended to increase
in recent years.

Discards in the world’s marine fisheries – an update
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TABLE 8
Discard rates and discards in shrimp trawl fisheries
Shrimp trawl fisheries
Discard rate for set of all records1 with a
discard rate
Discard rate and discards for set of complete records
(records with landings, discards, discard rate)
Average
discard rate
(%)
No. records Standard
deviation
Average
discard rate
(%)
No. records Standard
deviation
Landings
(tonnes)2
Discards
(tonnes)
Weighted
discard rate3
(%)
Column 1 2 3 4 5 6 7 8 9 [8/(8+7)]
Coldwater shrimp, various (South America, North Sea) 44.0 7 0.34 44.0 0.34 77 060 123 125 61.5
Crangon (Belgium) 83.3 1
Deepwater shrimp, various467.7 4 0.35 43.8 2 0.28 4 403 1 697 27.8
Deepwater shrimp, Mediterranean 39.2 3 0.09
Nephrops 50.1 7 0.13 45.2 5 0.37 14 722 10 954 42.7
Nephrops and deepwater shrimp, Mediterranean 56.5 4 0.16 70.0 2 0.12 11 086 70 000 86.3
Nephrops and deepwater shrimp, not Mediterranean 31.0 4 0.13
Pandalus 11.6 9 0.17 11.6 9 0.17 235 966 13 512 5.4
Aggregate coldwater and deepwater 18 343 237 219 287 39.0
Tropical shrimp555.8 58 0.27 58.2 52 0.25 783 030 1 645 777 67.8
All shrimp trawl fisheries 97 77 1 126 267 1 865 064 62.3
1 Records used to compile this table exclude China as catches/landings attributable to targeted shrimp trawling could not be clearly identified.
2 Landings include landings of bycatch.
3 The weighted discard rate (column 9) is considered to be the most accurate and representative at a global level
4 Includes deepwater non-penaeid trawl fisheries in tropical areas, e.g. Aristaeidae, Solenoceridae.
5 Almost exclusively penaeid shrimp fisheries.
Source: discard database.

Discards in the world’s marine fisheries – an update
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reflecting discards of 1.6 million tonnes for landings of 0.78 million tonnes recorded in
the discard database.
Three countries, China, India and Thailand, all with low or negligible discard rates,
account for over half of the penaeid shrimp catch. Most shrimp trawl fisheries in South
and Southeast Asia have insignificant discards with the notable exception of the Arafura
Sea shrimp fishery. This fishery, shrimp fisheries in the Gulf of Mexico, Atlantic United
States, Ecuador and on the Guianas shelf account for a large proportion of discards from
tropical shrimp fisheries (see Annex A.2.1, Table 15). Several smaller shrimp fisheries
have discard rates in excess of 80 percent. These include the Kuwait, French Guiana,
Panama and Suriname fisheries. This study suggests a much lower level of discards
in present-day tropical shrimp fisheries than previously estimated (Teutscher, 1999),
which is one of the major contributing factors to a lower global discard estimate.
An extensive mix of species are discarded, including jellyfish, lizard fish, threadfin
bream and juveniles of many commercial whitefish species such as croakers, snappers
and emperors, which may be the target species of other fisheries.
Artisanal shrimp fisheries
Most records of artisanal penaeid shrimp fisheries indicated a negligible discard rate.
However, there are many exceptions, particularly when trawl, pushnets or similar
gears are used, e.g. San Miguel Bay baby trawl (25 percent discard rate), the Brazilian
north coast and the Trinidad and Tobago artisanal shrimp fisheries. Many small-scale
shrimp trawlers are motorized and some freeze the product on board. It is becoming
increasingly difficult to distinguish between small-scale and industrial shrimp fishing
vessels.
Coldwater shrimp and prawn
The coldwater shrimp trawl fisheries exhibit an even greater variety than the tropical
shrimp in terms of fishing gears, fishing depths and substrates. In aggregate these
fisheries have a weighted discard rate of 39 percent and contribute approximately 220
000 tonnes to the global discard estimate (see Table 8). The highest recorded discards
occur in Peru’s fishery (74 000 tonnes with a discard rate of 81 percent).
Many of the deepwater shrimp fisheries are located on the slopes of the continental
shelves (100–600 m depth) in both tropical and temperate regions. In the Mediterranean
and North Atlantic many of these trawlers also target Nephrops. Most of the discard
database records are from the Mediterranean and North Atlantic and indicate a high
level of discards (20–94 percent). The deepwater shrimp fisheries contribute over
70 000 tonnes to the global discard estimate. The main discards58 include small sharks
(dogfish), rays, hake and blue whiting.
The fisheries for Pandalidae (Pandalus, Heterocarpus sp.) concentrated in the North
Atlantic (Canada, Norway, Iceland) account for approximately 13 000 tonnes of
discards. The mandatory use of Nordmore grids and other BRDs in most of these
fisheries results in a relatively low discard rate (weighted discard rate of 5.4 percent).
There are no records in the discard database for the North Pacific fisheries.
The weighted discard rate for discard database records of Nephrops trawl fisheries59
is 43 percent for a total discard estimate of approximately 11 000 tonnes. In the North
Atlantic (North Sea and Irish Sea), discards from Nephrops fisheries comprise whiting,
haddock, starry ray and broken/undersized Nephrops and flatfish. The high discards
of juvenile whiting and haddock have been of particular concern to fishery managers.
58 170 taxa were represented in the discards of the Straits of Sicily fishery (Castriota, Campagnuolo and
Andaloro, 2001).
59 Nephrops vessels may land substantial quantities (>50 percent of landings) of bycatch species. Some EU
Nephrops fisheries may be uneconomical without the bycatch revenue, such that the definition of the
target species may be questionable.

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Obligatory use of square mesh panels for these fisheries in the waters of EU member
states has resulted in substantial decreases in discards. Continued progress with gear
selectivity and improved compliance with regulations are likely to reduce discards
further.
The Belgian Crangon beam trawl fishery has a discard rate of 83 percent. There are
no records in the discard database that refer to fisheries for the important sergestid
shrimps (21 percent of the global nominal catch), which have both a tropical and
coldwater distribution.
Turtle excluder devices (TEDs)
The use of TEDs appears to have little impact on the level of discards. Penaeid shrimp
fisheries in which use of TEDs is mandatory account for over 700 000 tonnes of
discards with a weighted discard rate of 75 percent (range 0–79 percent).
Bycatch reduction devices (BRDs)
BRDs are used in a wide range of shrimp fisheries with apparent discard reductions in
Pandalus fisheries (0.2–29 percent discards), less impact in other coldwater fisheries for
Nephrops and other species (44–50 percent discards) and even less impact in tropical
fisheries (67–89 percent discards). The low impact in some tropical fisheries may be
a result of poor enforcement of BRD regulations, since experimental results clearly
indicate significant reductions in unwanted bycatch. Shrimp fisheries in which BRDs
are mandatory accounted for almost 0.4 million tonnes of discards (weighted discard
rate of 62.8 percent). Although the discard database contains few details of catch
and discards in Pandalus fisheries, the extensive and compulsory use60 of Nordmore
grids and similar BRDs has reduced bycatch to less than 5 percent in many Pandalus
fisheries. Additional work is necessary to interpret and include additional information,
particularly from the ICES and NAFO areas, from Australia and from the Gulf of
Mexico.
There is clear evidence of bycatch reduction through the use of BRDs, in particular
in Australian and United States penaeid trawl fisheries. However, the use of BRDs is
not widespread in developing countries.61 Reduction in discards is more likely to arise
from increased utilization of bycatch, rather than reduction of bycatch. Many shrimp
trawl fisheries in developing countries are marginally profitable and any reduction in
shrimp catch through the use of BRDs may result in significant economic losses.
Trends
There are major differences between the reasons for discard reductions in the tropical
and temperate water shrimp fisheries. The tropical fisheries are located in the waters
of developing countries with a high demand for lower value bycatch fish, either for
human consumption or animal feed. In social and economic terms the total commercial
biomass extracted may be more important than shrimp biomass, i.e. the unstated fishery
management objective is to maximize the catch, irrespective of the species composition.
In contrast, the total biomass harvested in the temperate water shrimp fisheries is likely
to be reducing as a result of the introduction of square mesh panels, BRDs and other
measures. Overfishing of whitefish and the higher price of shrimp encourages fishers
increasingly to target shrimp, while the intricate predator-prey relationships between
crustacea and finfish further complicate management of many interrelated fisheries
(e.g. NAFO area, Barents Sea and North Sea).
60 For example, in Norway, Svalbard, Barents Sea, Greenland and Canadian shrimp fisheries.
61 An important GEF/United Nations Environment Programme (UNEP)-funded project, “Reducing
the impact of tropical shrimp trawling fisheries on living marine resources through the adoption of
environmentally friendly techniques and practices”, is addressing this issue. Kenya has recently made
BRDs mandatory in its penaeid shrimp trawl fishery.

Discards in the world’s marine fisheries – an update
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TABLE 9
Discard rates and discards in non-shrimp trawl fisheries
Non-shrimp trawl fisheries1
Discard rate for set of all records with a discard
rate
Discard rate and discards for set of complete records(records
with landings, discards, discard rate)
Average
discard rate
(%)
No. records Standard
deviation
Average
discard rate
(%)
No. records Standard
deviation
Landings
(tonnes)4
Discards
(tonnes)
Weighted
discard rate2
(%)
Column 1 2 3 4 5 6 7 8 9 [8/(8+7)]
Demersal finfish320.80 102 0.17 18.60 63 0.16 3 182 715 775 396 19.60
Flatfish439.30 24 0.22 36.10 19 0.21 355 048 401 268 53.1
Other trawl fisheries 8 n.a. 7 900 628 258 570 n.a.
Midwater58.60 45 0.13 10.00 34 0.15 4 165 807 152 959 3.50
Demersal multispecies611.30 19 0.21 6.90 16 0.18 12 149 328 131 682 1.10
Deepwater733.80 9 0.29 32.50 6 0.37 56 899 37 276 39.60
Cephalopod 24.80 6 0.16 18.50 4 0.16 117 404 34 612 22.80
Fishmeal80.80 8 0.01 0.80 8 0.01 1 244 300 9 296 0.70
Total 19.1 221 16.9 157 0.20 22 172 129 1 801 059 7.5
Hake trawlers (ice and freezer)920.4 14 0.17 1 008 201 144 423 12.5
Factory trawlers 28.8 16 0.19 845 863 90 328 9.6
Beam trawl 34.6 5 0.35 173 290 399 068 69.7
1 The sheries are sorted on the basis of the primary target species. Additional details are provided in Annex A.
2 The weighted discard rate is considered to be the most accurate and representative at a global level.
3 Demersal nsh are sheries primarily targeting roundsh for human consumption.
4 Flatsh sheries include beam trawl sheries.
5 Midwater trawl sheries include some sheries that harvest for both shmeal and human consumption and include a large proportion of the Alaska pollock shery.
6 Demersal multispecies means that both nsh and shellsh are targeted. The reason for the low discard rate is because of the inclusion of Chinese and Southeast Asian trawl sheries in this group.
7 Deepwater sheries include those targeting orange roughy, Coryphaenoides and Molva species.
8 Fishmeal sheries are those specically targeting small pelagics for shmeal.
9 The hake, factory trawler and beam trawl values are presented separately. The reported landings and discards from these sheries are already weighted in the total in the preceding line.
Source: discard database.

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3.3.2 Non-shrimp trawl fisheries
The analysis distinguishes between a number of non-shrimp trawl fisheries, each of
which is discussed in more detail below and summarized in Table 9. These fisheries,
operating in 49 countries, include:
• demersal finfish trawl, primarily targeting roundfish;
• flatfish (e.g. plaice, sole, flounder) trawl fisheries, including several beam trawl
fisheries;
• hake trawl (both ice and freezer vessels combined);
• beam trawl, including those targeting flatfish;
• deepwater trawl fisheries, including those for orange roughy and grenadier;
• cephalopod fisheries targeting squid, octopus and cuttlefish;
• fishmeal fisheries;
• midwater trawl fisheries, some of which may harvest for fishmeal;
• factory trawlers, including the “catcher processors” in GOA/ BSAI; and
• an important group of trawl fisheries termed “demersal multispecies” which target
several phyla including finfish, cephalopods and crustacea, i.e. these fisheries
cannot be readily included in any of the preceding groups.
Details of the discards in these fisheries are provided below and in the supplementary
tables in Annex A, Tables 16–19. The fisheries are considered both in relation to the
gear used and the target species.
Trawl fisheries with the highest discards include the North Sea beam trawl fisheries;
Japan’s small trawl fishery; the Washington/Oregon/California groundfish fishery;62
and industrial trawl fisheries in Morocco and Argentina. Substantial discards also occur
in South Africa and Angola. The midwater trawl fisheries for small pelagics have the
lowest discard rates and are also discussed in Section 3.3.4.
Bottom otter trawl
Bottom otter trawl for finfish is one of the most common fishing gears. Fish landed
for direct human consumption has been estimated to be between 13.9 and 17.9 million
tonnes (Chopin, in press), or in the order of 20 percent of global marine fishery
production (excluding plants). Nineteen trawl fisheries involving 13 countries generate
80 percent of the estimated global bottom trawl landings.
The landings of an equivalent discard database set of fisheries total 15.9 million
tonnes with discards of 1.3 million tonnes or 19 percent of the estimated total discards
reported in the discard database. The weighted discard rate of these otter trawl fisheries
is 7.6 percent.
Among the main finfish fisheries contributing to these discards are the hake fisheries
in Argentina, the cephalopod and finfish trawl fisheries in Morocco, the French trawl
fisheries in the Bay of Biscay and Celtic Sea, and Japanese fisheries for Alaska pollock.
Fisheries with high discard rates include the offshore finfish trawl in Bangladesh, the
Algarve finfish trawl (Portugal), several Spanish and Greek Mediterranean fisheries,
and several United States fisheries (GOA Alaska pollock bottom trawl, silver hake).
Important demersal multispecies (i.e. targeting other phyla in addition to finfish)
otter trawl fisheries include the Japanese “small trawl” fishery, India’s east coast trawl
and the Chinese, Myanmar and Thai trawl fisheries which in aggregate contribute over
350 000 tonnes of discards.
Beam and pair trawl
Beam trawl finfish fisheries in the EU show discard rates ranging from 14 to 69 percent.
The finfish beam trawl fisheries account for 330 000 tonnes of discards and have a
weighted discard rate of 68.7 percent. These discards are primarily from the plaice and
62 While the fishery is predominantly a trawl fishery, pots, lines and other gears are also deployed.

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sole fisheries in the North Sea. Shrimp beam trawl discard rates range from 8 percent
(Pandalus, Canada) to 83 percent (Belgium). Pair trawl fisheries (from Spain, Viet Nam,
China and Brazil) for which discard records are available are considered too diverse to
be grouped. Discard rates range from 1 to 45 percent.
Flatfish trawl
Flatfish trawl fisheries have a significantly higher discard rate (weighted rate 51.3 percent)
than all other non-shrimp trawl fisheries, contributing 0.4 million tonnes to the global
total. Discards in EU fisheries include cod, haddock, whiting, plaice, saithe, dab,
dogfish, shrimp and Nephrops. Substantial quantities of invertebrates (Echinocardium,
starfish and crabs) are also discarded. Arrowtooth flounder is a major component of the
discards in the GOA/BSAI fisheries for yellowfin sole, flathead sole and other flatfish.
The reasons for the high discard rates in these fisheries are not clear, although the flat
muddy and sandy inshore habitats of many flatfish species may serve as important
nursery grounds with concentrations of juvenile fish of non-commercial sizes.
Factory trawlers
Factory trawlers are considered to be those with a fishmeal plant on board and/or those
producing surimi. Lack of information on the technical characteristics of vessels active
in a given fishery precludes clear identification of factory trawlers and, by extension, of
factory trawl fisheries. Consequently, discard information on this category of fishery
remains tentative. Recorded discards are 90 000 tonnes for a weighted discard rate of
9.6 percent based largely on records of “catcher processor” vessels in the GOA/BSAI
groundfish fisheries. Argentine surimi vessels, targeting southern blue whiting and
grenadier, are understood to have low or negligible discards. It is likely that substantial
quantities of fish that were hitherto discarded are now processed by such vessels and
that there are increased discharges of offal, either in liquid or solid form.
Hake trawl
Hake is a major target of the demersal finfish trawl fisheries. Trawl fisheries in more
than 25 countries harvest the vast majority of the global hake landings of 1.9 million
tonnes (Merlucciidae). Argentina dominates the landings (over 0.5 million tonnes)
followed by Chile/Peru (0.36 million tonnes), the Namibia/South Africa fishery and a
range of United States fisheries.
In the discard database, hake fisheries account for almost 150 000 tonnes of
discards for landings of approximately 1 million tonnes and a weighted discard rate of
12.5 percent. The combined Argentine ice and freezer trawl hake fisheries have discards
of 30 000 tonnes and a weighted discard rate of 13.9 percent (range: 9.9 percent for
freezer trawlers to 19.8 percent for offshore ice trawlers) followed by Chile with over
26 000 tonnes of discards. Discards include small hake and horse mackerel (all fisheries),
kingklip and rattails (Africa), arrowtooth flounder, dogfish and ratfish (North Pacific).
Minimum size regulations, quotas and bycatch quotas (Chile) are among the reasons
for discarding. Namibia pursues a “no-discard” policy’ although “non-commercial
species” may be discarded.
Fishmeal demersal trawl fisheries
The discard database records are exclusively from the North Sea/Kattegat/Skaggerak
fisheries for sand eel and Norway pout. Landings of over 1 million tonnes have discards
under 10 000 tonnes with a weighted discard rate of less than 1 percent.
Deepsea (deepwater) finfish fisheries
Several different types of gear, including trawls, longlines and gillnets are used in
these fisheries and growing concern has been expressed over the status of these

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deepsea or deepwater fisheries (FAO, 2003b). Many of the fishing grounds are
located on continental slopes and high seas plateaus or on seamounts outside coastal
state jurisdiction. With the exception of small-scale dropline fisheries, discards are
considered high in many deep sea fisheries.
The discard database records are from fisheries in the Northeast Atlantic (Gordon,
1999) and Chile and give a weighted discard rate of 39.6 percent (range 31–90 percent)
and total discards of 37 000 tonnes. These fisheries target grenadier (Coryphaenoides),
ling, seki shark and orange roughy. Discards have been particularly high in the French
fishery for roundnose grenadier. Discarded teleosts include grenadiers, whiptails,
rabbitfish and oreos. The discards also include a range of chondrichthyans (sharks such
as birdbeak dogfish [Deania], batoids and chimaeroids), some of which also constitute
part of the retained or target catch (e.g. seki shark in the Hatton Bank/Rockall Trough
fisheries). There is evidence that survival of discards from these fisheries is low
(Conference Steering Committee, 2003).
The discard database does not contain records of other important deepsea fisheries,
e.g. off Namibia and New Zealand and exploratory fisheries such as those for
deepwater crab (Hawaii area) and lobster (off Brazil). The Patagonian toothfish fishery
is discussed in Section 3.2.10.
Midwater (pelagic) trawl for demersal species
With catches of over 1.2 million tonnes, the Alaska pollock fishery entirely dominates
this category. The discard rate here is less than 1 percent and discards are comprised
almost entirely of undersized or damaged pollock (see Annex A.6.1 for details). In
contrast, other midwater63 trawl fisheries have discard rates ranging from 1 percent for
Atlantic redfish in Canada to 54 percent for hake in France. Discards in these fisheries
include horse mackerel, mackerel, pilchard and black bream.
Midwater (pelagic) trawl for small pelagics
The recorded landings of over 2 million tonnes have discards of under 100 000 tonnes
and a weighted discard rate of 4.2 percent. The major fisheries in Iceland (blue whiting,
capelin), Norway (blue whiting, capelin) and Namibia (horse mackerel) all have discard
rates of less than 2 percent, as do the fisheries for southern blue whiting (Argentina
and the Falkland Islands [Malvinas]). Fisheries in the more southerly waters of Area 27
appear to have a greater species mix and higher discards. An estimated 35 000 tonnes is
discarded in the combined Netherlands and Irish mackerel and horse mackerel fisheries
(Area 27) with discard rates in the order of 11 percent. A substantial proportion of
the Netherlands and Irish catch is taken off West Africa where discard rates are in the
2–6 percent range. Russian (and former Soviet bloc) midwater trawlers operating in the
North Atlantic generally have negligible discards as potential discards are converted to
fishmeal on board. The highest discard rates of up to 38 percent are recorded from the
French pelagic trawl fisheries in the Bay of Biscay.
Discarded species include horse mackerel (EU countries), sardine, pilchard,
mackerel and sprat. Dolphins (1.4 dolphins/100 tow-hours in French and Irish tuna
fisheries) and sunfish are caught incidentally. Small-sized fish of the target species may
be discarded as a result of highgrading in the quota-managed European fisheries or
because processing equipment cannot handle smaller sizes.
Cephalopod trawl
Discard rates in the cephalopod trawl fisheries range from 3 percent in the fisheries
for pelagic species (Loligo, Ilex) in the Falkland Islands (Malvinas) to 45 percent in
63 Note that bottom trawls may fish the entire water column in some areas, e.g. shallow parts of the
Baltic.

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the fisheries for octopus (Morocco, Mauritania, Japan). Guinea’s cuttlefish-directed
trawl fishery has a discard rate of 24 percent. These fisheries produce approximately
35 000 tonnes of discards and have a weighted discard rate of 22.8 percent.
3.3.3 Tuna and HMS fisheries
Discards in the tuna and HMS fisheries were assessed by ocean since information
on catches and fishing activities is collected by five regional fisheries management
organizations (RFMOs) and regional fisheries bodies (RFBs)64 by fishing gear and
country. The catch databases maintained by the RFMOs generally include catch
information by country and gear, but do not necessarily discriminate catches by fishery.
While in some cases the catch for a discrete fishery can be inferred (e.g. Maldives pole
and line), in many cases it is not clear whether the reported tuna catch originates from
a targeted tuna fishery or is a bycatch of another fishery (e.g. gillnets in the Indian
Ocean). Every attempt has been made to avoid double accounting65 for tuna catches
also recorded as part of national fisheries statistics.
Two relatively comprehensive studies have been made of discards in the SPC area.
In the case of the Atlantic HMS fisheries little quantitative information on discards
was located. Table 10 summarizes discards and discard rates. Tuna catches in troll and
gillnet fisheries cannot readily be separated from catches of other large pelagics.
Longline
There are significant differences between distant water longline fleets that target
different species, even for those fleets with the same flag. Smaller longliners will tend to
have shorter trips and retain more sharks and other non-target species. The long-range
(mostly Asian) vessels are likely to discard greater quantities of bycatch (Nishida and
Shiba, 2002). Discard rates for the long-range vessels range from 30 to 40 percent. The
SPC discard rate of 40 percent is applied in the absence of other information and a rate
of 15 percent is applied to the smaller, locally based longline vessels. Principal discards
include Prionace glauca (blue shark), which is probably the most commonly discarded
species, Carcharinus sp. and other sharks, damaged fish, albatross, petrels and other
seabirds. Landings of sharks, frigate tuna, Kawakawa, Indo–Pacific king mackerel,
and narrow-barred Spanish mackerel are not recorded in the IOTC database and it is
assumed that industrial longliners discard the catch of most of these species. Discard
rates in swordfish longline fisheries vary between 10 percent (Canada and Seychelles)
to 19 percent in the Atlantic United States. Hook drop-off is not considered to be a
discard.
Purse seine
Discard rates vary from 1.5 percent in small (<400 GRT) Mexican seiners to 6.9 percent
in the IATTC area. Other discard rates are Atlantic, 4.1 percent; Indian Ocean,
5 percent; and SPC area, 5.9 percent. Total recorded discards are approximately
145 000 tonnes. Discards include undersized target species, non-commercial tunas,
shark, rainbow runner, dolphinfish, triggerfish, billfish and mantas. Large quantities of
jellyfish are discarded in the bluefish and bonito fisheries in Turkish waters. Incidental
catches of dolphins are discussed in Section 4.2.3.
64 Commission for the Conservation of Southern Bluefish Tuna (CCSBT), IATTC, ICCAT, IOTC and
SPC.
65 It has not been possible to separate tuna catches from other artisanal catches in some countries.
Consequently, if a discard rate is applied to a catch/fishery described as a “national artisanal multispecies/
multigear fishery”, then some double counting may have occurred. There is no double accounting with
respect to the tuna catches from the small-scale fisheries of the island countries of the South Pacific.

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Pole and line fisheries
These fisheries are essentially two fisheries – one for bait (usually anchovy) and the
main fishery usually directed at skipjack and yellowfin tuna. The major pole and line
fisheries are in the Western Pacific, Maldives, Japan, West Africa and Brazil. Discards
of approximately 3 000 tonnes give a weighted discard rate of 0.4 percent for catches of
over 0.8 million tonnes. Discards in baitfish fisheries have not been assessed.
Traps
Large anchored tuna traps are used on the coasts of Atlantic Morocco and Canada
and in Mediterranean countries including Italy, Libyan Arab Jamahiriya and Tunisia.
Tuna traps are quite selective and have a low or negligible discard rate, partly because
of the large mesh size used in the traps. Canadian fishers are obliged to release bluefin
tuna alive from traps licensed to catch herring and mackerel. Cetaceans may sometimes
become entangled in trap mooring lines.
Other tuna fisheries
Trolling, handlines and coastal gillnets targeting tuna are also considered to have a
low or negligible discard rate. Tuna gillnets are extensively deployed on the Indian
subcontinent where discards are generally negligible (e.g. the Sri Lanka offshore gillnet
fishery). Available records for harpoon fisheries (Nova Scotia swordfish) indicate zero
discards.
Sharks
A study of elasmobranch fisheries cautioned against extrapolating the catch rates from
one fishery to another because of the wide variation in the distribution of elasmobranchs
(Bonfil, 1994). It is likely that weights of discarded sharks and other species can be
derived from available66 longline observer data and a more accurate estimation of
discards can be made at the level of the RFBs. In the absence of recent comprehensive
data on shark catch as a percentage of total longline catch, older67estimates have been
used to determine a longline discard rate in the Indian Ocean of 21.7 percent of the
total catch. It is assumed that fish subject to predation are discarded (Nishida and
Shiba, 2002).
At the global level, assuming that carcasses of all finned68 sharks are discarded,
over 200 000 tonnes of shark are discarded annually as a result of finning (discard
TABLE 10
Discards and discard rates in fisheries for tuna and HMS
Fishery Longline Purse seine Pole and line Midwater
trawl Traps
Number of records 37 12 11 4 2
Average discard rate 22.0% 4.85% 0.1% – –
Standard deviation 0.16 0.02 0.003 – –
Total tonnage of records 1 403 591 2 673 378 818 505 60 050 4 693
Total discards of records 560 481 144 152 3 121 26 532 0
Weighted discard rate 22.0% 5.1% 0.4% 30.0% <1%
Source: discard database.
66 See Cramer, 1999; Walsh, Kleiber and McCracken, 2002. Models comparing logbook and observer
reports from the Hawaii longline fleet may also assist in providing more accurate estimates of global
shark catches/discards by longline fleets.
67 Based on Bonfil, 1994.
68 International trade in shark fins totals approximately 5 000 tonnes (recorded quantities as per FAO
Fishstat commodity statistics). Real quantities are considered to be closer to 9 000 tonnes (re-exports
excluded). Fins constitute approximately 2.5 percent of the live weight of the shark (5 percent of dressed
carcass weight). Trade information and fin yield information from IUCN Species Survival Commission
(SSC), Shark Specialist Group. Fin yield is derived from United States studies on Prionace glauca.

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Results 47
rate of 96 percent). Discards of sharks in high seas fisheries alone are estimated to be
204 000 tonnes annually (Bonfil, 1994).
3.3.4 Small pelagics fisheries
The fisheries for small pelagics generally have low discard rates because the schools
tend to be monospecific and the fish tend to be of a similar size. Tables 11 and 12 give
details by gear type, based on the information in the discard database.
Purse seine
Purse seines and other seines catch the vast majority of global small pelagics. These
seine fisheries contribute over 350 000 tonnes to the global discard estimate and have
a weighted discard rate of 1.6 percent. Purse-seine fisheries in Peru, Norway, Chile
and Iceland are the main contributors of discards. Because of the volume of catches,
even with a low discard rate of 2.5 percent the Peruvian anchoveta fishery discards
approximately 250 000 tonnes. Many small pelagic purse-seine fisheries are considered
to have a zero discard rate, including United States menhaden, Black Sea anchovy and
Malaysian and Vietnamese anchovy. Among the fisheries with the highest discard
rates are those in Portugal, Spain and France targeting sardine, mackerel and anchovy.
Discards in these fisheries are primarily of other non-target small pelagics including
horse mackerel, Scomber japonicus, Boops, Belone sp., jellyfish, juveniles of other
species51 and small quantities of sharks.
Midwater trawl
These fisheries have already been discussed in Section 3.3.2. With the exception of
the South African midwater trawl fishery for small pelagics (43.9 percent discard
rate), all other high discard rates are from EU fisheries (seven records ranging from
10 to 47 percent). The quota regulations are a major cause of high discards in all these
fisheries.
Slipping of unwanted fish is common in industrial fisheries for small pelagics. The
quantity of such discards is particularly difficult to assess.70 Norway has made use of
crewless video-equipped submersibles to monitor slipping and discards in some of
these fisheries.
Among the “other” industrial small pelagics fisheries, those with the highest discard
rates are the Norwegian herring seine fishery (7 percent), the eastern Black Sea coastal
encircling gillnet (7.4 percent), and Ireland's herring trawl (4.7 percent).
TABLE 11
Discards and discard rates in industrial fisheries for small pelagics
Fishery Midwater/pelagic trawl Seine/purse seine
Number of records 19 52
Average discard rate 5.7% 2.0%
Standard deviation 0.7 0.03
Total tonnage of records 2 763 040 21 664 338
Total discards of records 101 285 351 111
Weighted discard rate 3.5% 1.6%
Note: industrial and semi-industrial only. By industrial is meant industrial scale. Industrial does not mean fishing for
fishmeal.
Source: discard database.
69 Recent Norwegian experimental work with surface trawls has shown that significant catches of salmon
smolts are caught in the mackerel fishery, possibly accounting for a significant percentage of the total
recruits available.
70 “I don’t see small mackerel landed any more.” Fisheries inspector, Ireland, 2003, on the subject of
highgrading.

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Artisanal
Lift nets, pushnets, beach seines, surround nets,
gillnets trolling and a wide variety of other gears
deployed in the artisanal fisheries for small pelagics
are all considered to have low or negligible discard
rates. Senegal produces over 250 000 tonnes of
small pelagics with a fleet of outboard powered
purse seiners. Numerous other artisanal purse seine
fisheries exist producing a large, but unknown quantity of small pelagics (e.g. Bali
Straits sardine fishery, Thai coastal fisheries). Mesh size regulations in these fisheries
may contribute to discards since smaller fish can become gilled in the nets. Discard rate
for such groups of fisheries are not available.
3.3.5 Gillnet fisheries
Surface and bottom gillnet fisheries (including trammel nets) account for under
30 000 tonnes of discards from reported landings of over 3 million tonnes (a weighted
discard rate of 0.5 percent). The high level of catch is largely attributable to the
Chinese small drift gillnet fishery (2.3 million tonnes). Source references do not always
distinguish between surface and bottom gillnets and available gillnet catch statistics
may combine both. The gillnet fisheries are highly diverse and would benefit from
further disaggregation. They range from deepwater gillnets for hake and monkfish
(Area 27, western waters) to surface nets for large pelagics, trammel nets for shrimp
and crab and tangle nets for lobster. Some gillnet fisheries may target roe fish such as
lumpfish and herring. Dropout from gillnets is not considered a discard. Among the
highest discard rates are California’s drift swordfish gillnet fishery and the sink gillnet
fisheries in the northeastern United States, Canada’s Greenland halibut fishery (1994
data) and Norway’s lumpfish fishery.
Discards include dogfish, skate, sculpin (Canada), cod, haddock, plaice, saithe and
dab (Europe). Coastal gillnet fisheries in France have low discard rates for marketable
finfish, while offshore gillnet fisheries with soak times of up to six days may discard
100 percent of gadoid species because of the poor phytosanitary condition of otherwise
marketable finfish (Morizur, Pouvreau and Guénolé, 1996). A number of countries
prohibit monofilament gillnets but enforcement of such regulations is highly variable.
3.3.6 Non-tuna line and jig fisheries
In aggregate the non-tuna line fisheries have a weighted discard rate of 7.5 percent and
discards of 47 000 tonnes. The bottom longline fisheries have a similar weighted discard
rate of 7.5 percent, while the handline fisheries show a discard rate of 2 percent.
The BSAI catcher processors targeting Pacific cod contribute over 24 000 tonnes of
discards, while the GOA shoreside fleet targeting rockfish shows the highest discard
rate (57.4 percent). In addition to the generally high discard rates in the GOA/BSAI
line fisheries, toothfish longline (discard rates above 20 percent), artisanal shark
fisheries (Peru and elsewhere) and longline fisheries in Norway and Spain (hake) have
discard rates in excess of 10 percent.
Discarded species include arrowtooth flounder (GOA/BSAI fisheries), starry ray,
dab and redfish (Iceland, the Faeroe Islands), hake, shark and kingklip (South Africa),
and macrourids and rajids in the CCAMLR area. In many of these fisheries in Europe
and the United States some discarding is attributable to highgrading and species-
specific per vessel quotas.
Jig fisheries
Jig fisheries tend to be highly selective with a weighted discard rate of 0.1 percent for
the squid fisheries and 3.5 percent for finfish fisheries (cod, Pacific cod and mackerel).
TABLE 12
Other industrial fisheries for small pelagics
Gear type Range of discard rates
Danish seine and other
unspecified seines Negligible –7%
Trawl gears (unspecified) Negligible – 4.7%
Gill nets Negligible – 7.4%
Troll Negligible

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Additional details on these sheries are provided in Annex A.2.2, Table 20.
3.3.7 Multigear and multispecies fisheries
Over 100 fisheries in the discard database were classified either as multigear, as
multispecies or as both multigear and multispecies. In many cases this unhelpful
designation reflects an aggregation of several fisheries and can be largely attributed to
the manner in which statistical information is compiled at national level. Further work
could disaggregate each of such “multi” fisheries into a set of differentiated fisheries.
Nevertheless, in many fisheries, individual vessels deploy different gears during the
same fishing trip and in some cases, e.g. many Asian trawl fisheries, “there is no target
species because all species are the target”.71
Most of the fisheries in this group are small-scale fisheries. The artisanal fisheries of
the Pacific Islands and Caribbean comprise 43 of the records in this group of fisheries
and have an assumed discard rate of 0 percent. The highest discard rate is reported
from the multigear shrimp fishery in northern Brazil (50 percent) and the Uruguayan
artisanal multigear fishery (15 percent). The weighted discard rate is 1.4 percent,
representing discards of 85 000 tonnes from landings of over 6 million tonnes.
3.3.8 Fisheries using other gears
Dredge
Discard rates in dredge fisheries, which are mainly directed at scallops, clams and
whelks range from 9 to 60 percent with a weighted average of 28.3 percent and a
contribution of over 65 000 tonnes (ten records) to the total discard estimate.
Pushnet
Pushnets exhibit a wide range of discard rates from 90 percent for those collecting penaeid
post larvae (Bangladesh) to 0–1 percent for those operating in the Gulf of Thailand and
South China Sea, many of which are operated from larger motorized vessels
.
Bagnets
Bagnets (five records from Asia and Africa) have a discard rate of less than 1 percent
and make a negligible contribution to the total discard estimate.
Other fixed nets
Chinese landings of over 2.6 million tonnes from “stationary” nets dominate the
category and have an assumed discard rate of 0.5 percent. Total fixed net discards
are estimated to be approximately 24 000 tonnes. With the exception of the Guyana
Chinese “seine” (a type of staked fyke net) with a discard rate of 25 percent, all these
fisheries (six records) have discard rates below 1 percent.
Traps
Three main types of trap fisheries are distinguished: fixed traps (12 records), small-
scale pots and industrial pots. The tuna trap fisheries (Mediterranean and Canada) and
the small-scale fixed and arrowhead traps of Asia incur negligible discards. Octopus
pots (West Africa, Japan) also have negligible discards. Lobster and crab pots often
have high regulatory discards, as fishers are obliged to discard females and undersized
specimens in many jurisdictions. In contrast to the negative connotation of many
discarding practices, discards with a high survival rate are highly desirable for stock
conservation. High discards in several major crustacean pot fisheries, e.g. BSAI crab
fishery (over 40 percent) and Canadian lobster fisheries (23 percent) account for high
71 Bureau of Fisheries, Ministry of Agriculture, Beijing, pers. comm. (2003).

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discard rates of 12.4 percent (average 12 records) and 27.7 percent (weighted discard
rate). Finfish pot fisheries (14 records) indicate a maximum discard rate of 5.2 percent
with the exception of an experimental fishery for toothfish in the CCAMLR area,
which has high discards of crabs and other species (61 percent). Finfish pot fisheries
account for under 1 500 tonnes of the total discard estimate.
Other gears
Harpoons, used for swordfish in Canada and the United States, are highly selective and
unlikely to incur discards. The saury stick-held dip net (Japan), dip nets in Viet Nam
and scoop nets in peninsular Malaysia have low to negligible discards.
3.3.9 Artisanal and small-scale fisheries
The terms “artisanal” and “small-scale” fisheries are considered equivalent for the
purposes of this study and embrace other categories (e.g. subsistence, traditional,
indigenous) used in the national fisheries statistics or fishery terminology of different
countries.
While most of these fisheries have been assumed to have a low or negligible discard
rate, it is clear that some discarding takes place. Puffer fish, “ciguatera” fish and other
poisonous species are discarded. Fish gilled in seine nets may be discarded. Hooked
fish damaged by shark attack may also be discarded, although fish heads are often
retained. Small quantities of living marine resources are often discarded in beach-
seining operations. Many artisanal fisheries are highly selective,72 e.g. trammel nets
targeting shrimp may discard quantities of crabs that become entangled and broken.
Artisanal trawlers in Southeast Asia discard benthos such as sponges and tunicates and
“baby trawls” in the Philippines have relatively high discard rates. Estuarine stake nets
tend to have significant discards. “Jellyfish” of several phyla are frequently discarded.
Nevertheless, little information exists in the available literature quantifying these
discards, since discarding is generally not considered to be a priority concern in small-
scale and artisanal fisheries. More frequently post-harvest losses are the primary
concern. Numerous national experts consider that discards in their national artisanal
fisheries are negligible (see Annex C.5, Table 35). Efforts have been made to identify
the artisanal73 or small-scale component of national landings and, in the absence
of information to the contrary, these fisheries have been assumed to have a low or
negligible discard rate.
Partly as a result of problems arising from the definition of fisheries at the national
level, it is difficult to separate clearly artisanal (small-scale) fisheries from industrial
fisheries. Consequently, a comparison between the discard rates of these sectors is
difficult. However, is quite clear that the vast majority of discards originate in the
industrial sector.
Discard database records indicate that catches of at least 8.5 million tonnes can
clearly be attributed74 to small-scale fisheries. In aggregate these fisheries show a
discard rate of 3.7 percent.
72 Bundy and Pauly, 2001. This research indicates that a set of highly selective artisanal non-trawl gears
exploit a greater range of species and niches than the less-selective trawlers. The set of artisanal gears are
judged to have a more detrimental effect on the ecosystem. This suggests that studies may be required
prior to advocating substitution of trawls with more selective gears.
73 That is, the definition of “artisanal/small-scale” adopted by national fisheries authorities for the purposes
of national fisheries statistics has been used in each case.
74 Hand line and diver fisheries are clearly small-scale. However, it is unclear in many cases whether the
fishery is small-scale or industrial. This means that the 8.5 million tonnes referred to above is a minimum,
particularly as the study has been unable to separate catches from many Asian fisheries (e.g. China,
Viet Nam) into small-scale and industrial.

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Beach seine
The average discard rate (32 percent) is high because beach seines in developed
countries (e.g. Australia, Portugal) have high discards. However, the highest landings
from beach seines take place in developing countries where the activity has a high
social importance and discards are often negligible since even low value fish is used for
autoconsumption and crew compensation. The weighted discard rate is 4.4 percent,
whereas Table 5 lists beach-seine fisheries in developing countries among the fisheries
with a negligible discard rate.
Diver
Diver fisheries (12 records) for abalone, clam, topshell and mother of pearl, lobster,
octopus and rare shells all have a zero or negligible discard rate (<1 percent). Damage
or mortalities caused by divers to corals or other species has not been estimated
although it is reported to be substantial in some areas (e.g. cyanide fishing for live reef
fish, “excavating” giant clams or harvesting ornamental corals). Discards of sea urchins
may be substantial if gonad condition is poor.
Hand collection
Hand collection, also referred to as hand gathering or gleaning, is a common artisanal
and commercial fishing activity. Many collection activities, e.g. for cockles and clams,
take place during low-water spring tides. Substantial damage may occur to reefs from
walking on corals or overturning rocks. Damage and mortalities may also occur from
raking or dragging baskets and sacks and from collection vehicle movement (e.g.
tractors). Such damage is not considered a discard. Substantial collection fisheries exist
in Chile, Japan and Thailand. Discards in all cases (16 records) are negligible (<0.5
percent) and these fisheries contribute no more than 1 000 tonnes to the total discard
estimate.
3.3.10 Discarded species
It is difficult to determine the most important discards by species or species group since
the composition of the discards is often inadequately recorded. Most studies focus on
the discards of commercial species and it is often unclear whether non-commercial
species are recorded, e.g. there are few references to discards of jellyfish. A particular
study may provide a list of discarded species without specifying the quantities
discarded, or generic designations such as “juveniles of commercial species”, “non-
commercial species” or “invertebrates” may be used in the literature. The quantity
of discarded invertebrates may be significantly under-reported. Significant discards
of sponges, coelenterates75 including corals, Ctenophora, echinoderms, tunicates and
crabs occur, particularly in trawl and dredge fisheries. Often only the weight of the
discarded commercial species is reported. Percentages by weight of the different species
are rarely provided or, if provided, it may not be possible to relate the percentages to
the total or retained catch. Consequently, little quantitative information on discards
by species is contained in the discard database. A synthesis of selected information is
provided in Annex A.5, Table 25.
For the purposed of discard estimation a division of the catch into three groups
may be useful: species always retained; species always discarded; and species partially/
sometimes discarded. If estimates of the overall catch composition are available,
observers may then concentrate on the partially discarded species. Further analysis
of the composition and quantity of discarded species may suggest a more effective
targeting of market and product research to facilitate greater utilization of these
75 High catches and discards of jellyfish are recorded in many fisheries, e.g. South Atlantic shrimp trawl
(United States), purse seines for bluefish in the Bosporus, the Kimberly coast prawn trawl.

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species, and assist in studies on biodiversity and
on the impact of fishing on marine ecosystems.
3.3.11 Regulatory measures and discard
rates
Analysis of the discard database records by type
of regulatory measure, summarized in Table 13,
is not particularly useful because of the variety
in the fisheries, the influence of other regulatory
measures and the weak enforcement of some
measures. The “no-discards” regime will be
examined in more detail in Section 4.3.1.
MLS
Many fisheries apply several regulations that
directly influence discard rates. MLS regulations,
which clearly promote discarding, are often associated with other regulations (e.g.
closed areas, closed seasons or quotas) and the impact of a particular regulation is
difficult to assess. In some cases the MLS is set below the marketable size. For example,
reducing the MLS for whiting in the North Sea would have little effect on discard
practices because there is no market for the small whiting. However, a reduced MLS
for hake may have an effect in Spain where there is a ready market for small hake.
Although there are MLS regulations in many Southeast Asian countries, the generally
low discard rates reflect the weak application of these regulations. Sales of unsorted
fish, such as “African mix” in West Africa, bycatch purchased at sea by collection
vessels, often circumvent the MLS regulations.
TEDs and BRDs
Shrimp fisheries using TEDs do not appear to have an appreciably lower discard level
(aggregate discard level 62.3 percent) than those that do not use them. Discard rates in
fisheries using BRDs range from <6 percent in the NAFO area (as low as 0.2 percent)
to 88.7 percent in Australia and Indonesia (Arafura Sea). Time series showing discard
rates before and after the introduction of TEDs and/or BRDs are necessary to provide
a more accurate assessment76 of the impact of these devices. The broad range of discard
rates is also partly attributable to varying levels of enforcement of the TED/BRD
regulations.
76 See studies from Australia and the Gulf of Mexico, e.g. Kennelly, 2000.
TABLE 13
Weighted average discard rates for fisheries using
different discard-related management measures
Measure Discard rate (%)
Turtle excluder device (TED) 62.3
Minimum landing size (MLS) 50.9
Bycatch reduction device (BRD) 43.9
Obligatory bycatch landings 32.2
Obligatory release of certain species 19.8
Bycatch quotas 19.8
Observers 18.4
Area closures 10.5
Time closures 9.9
Bycatch plan 7.6
Multiple measures 3.8
Discard ban 3.6

53
4. Issues
4.1 WHAT IS “THE DISCARD PROBLEM”?
The expression “the discard problem” embraces several issues or subproblems, which
go to the foundations of fisheries management philosophy and practice. Several
subsidiary problems and issues can be identified (Hall, 1994).
• Policy and ethical issues. Discards are seen as a waste of natural resources, contrary
to responsible stewardship and sustainable utilization of marine resources.
• Fisheries management issues: the difficulty in designing and implementing
a management regime that meets multiple social, economic and biological
objectives, while limiting or preventing discarding, or avoiding the catch likely to
be discarded.
• Ecological issues related to the impact of discards on marine ecology.
• Technical and economic issues: the technical problems of gear selectivity and
utilization of species with a low market demand through transformation, or
adding value; the economic problems posed by efforts to reduce bycatch, increase
landings of bycatch or increase its utilization.
4.2 POLICY ISSUES
4.2.1 International instruments and guidance
The international community has recognized both ethical concerns and policy
regarding discards, related biodiversity and endangered species in several international
instruments and statements, including United Nations resolutions,77 multilateral
agreements and plans of action (see Box 1).
The initial UN resolution (49/118) invited international organizations to:
• include provisions with regard to bycatch and discards in international instruments,
including the United Nations Agreement relating to the Conservation and
Management of Straddling Fish Stocks and Highly Migratory Fish Stocks and the
Code of Conduct for Responsible Fisheries;
• review the impact of fisheries bycatch and discards on the sustainable use of living
marine resources; and
• recognize the need for greater monitoring and assessment of bycatch and discards
and for continued improvement in bycatch reduction techniques.
Subsequent resolutions 50/25 and 51/36 of 1996 called for states and regional
fisheries organizations to: adopt policies, apply measures, collect and exchange data and
develop fishing techniques to reduce bycatches and fish discards; place “discards” on
the United Nations General Assembly (UNGA) Law of the Sea (LOS) agenda; provide
assistance to developing countries to collect and exchange data and develop techniques
to reduce bycatches and fish discards; and requested the Secretary-General to submit
biennial reports to UNGA relating to the implementation of the resolutions.
Resolution 52/29 of 1997 recalled that the Agreement relating to the Conservation
and Management of Straddling Fish Stocks and Highly Migratory Fish Stocks provides
in its general principles that states shall minimize discards and reaffirmed the previous
UN resolutions.
77 The resolutions are A/RES/49/118 (1994); A/RES/50/25 (1996); A/RES/51/36 (1996); A/RES/52/29
(1997); A/RES/53/33 (1998); A/RES/55/8 (2000); and A/RES/57/142 (2002).

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Resolution 53/33 of 1998 recognized the progress in the preparation of draft plans
of action in relation to shark fisheries and the incidental catch of seabirds and drew
further attention to incidental losses of sharks and seabirds.
Resolution 55/8 of 2000 expressed concern about the significant level of bycatch and
discards in several of the world’s commercial fisheries; recognized the importance of
the development and use of selective, environmentally safe and cost-effective fishing
gear and techniques for reducing bycatch and discards; acknowledged the value of
FAO, UNEP and GEF initiatives; and urged further action to reduce discards.
BOX 1
Selected multilateral initiatives
Agreement for the Implementation of
the Provisions of the United Nations
Convention on the Law of the Sea
(UNCLOS) relating to the Conservation
and Management of Straddling Fish
Stocks and Highly Migratory Fish
Stocks (United Nations Implementing
Agreement [UNIA])
… minimize ... discards, ..., catch of non-target species,
both fish and non-fish species, and impacts on associated
or dependent species, in particular endangered species ...
The Rome Consensus on World
Fisheries adopted by the FAO
Ministerial Conference on Fisheries,
Rome, 14–15 March 1995
... reduce bycatches, fish discards …
CCRF has numerous references1 to
discards
... collect information on discards ...; ... take account
of discards (in the precautionary approach) ...; ... take
appropriate measures to minimize waste, discards ...; ...
develop technologies that minimize discards ...; use of
selective gear to minimize discards; …
International Plan of Action (IPOA) on
sharks
Minimize waste and encourage full use of dead sharks
IPOA on seabirds Prevention of seabird capture and release of seabirds
Convention on International Trade in
Endangered Species of Wild Fauna and
Flora (CITES)
Under CITES, marine mammals, turtles and seabirds and
some fish species are listed under Appendix I (species
threatened with extinction that are or may be affected by
trade), and Appendix II (species threatened with extinction
unless trade is subject to strict regulations). CITES listing
may have a significant effect on fisheries that catch such
species
Convention on Migratory Species (CMS) The Convention has provided a forum for the development
of legally binding regional agreements on marine mammals
and turtles (e.g. ACCOBAMS and ASCOBANS)
Convention on Biological Diversity
(CBD)
Discards affect biodiversity2 along at least three axes:
species numbers, species densities and species dispersion.
These impacts are not well understood, particularly with
regard to benthos
1 For a discussion of the references to discards in the CCRF, see Clucas, 1997.
2 The role of discards in terms of broader ecosystem change, e.g. supporting seabird populations in the North Sea, has
been well documented.

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Resolution 57/142 of 2002 urged action to reduce or eliminate bycatch and fish
discards and drew attention to a range of appropriate measures.78
4.2.2 Ethics of discards
Many societies and religions adhere to the principle that human beings have a
moral obligation to make best use of natural resources and minimize wastage. In
others (Tucker, 1998), nature is seen as intrinsically valuable. Islam and many other
religions support the concept of stewardship (Afrasiabi, 1995), or that humans hold
nature in trust and are accountable to god for the use or misuse of nature. Buddhist
“environmentalism” is also based on an underlying belief in causal relationships
between living beings and human beings with an individual and general responsibility
for the state of nature. Shinto purification is performed to restore the balance between
humans, nature and the deities (Bernard, 1998). These themes are repeated in Judeo-
Christian beliefs and echoed in the saying “waste not, want not” and in several Biblical
ethical models (Bratton, 2000):
• “do not destroy”, which prohibits wanton disturbance of a productive nature;
• neighbourliness, a concept that prohibits damage to another family’s livelihood;
• divine ownership of and joy in creation, which assigns value to non-economic
species and to biodiversity; and
• stewardship, which requires both active resource protection and careful resource
use.
Throughout many of these belief systems there is an underlying theme that
technology alone cannot resolve the issues of human beings’ relationship with nature,
but that greater harmony and balance in the use of natural resources depend on values,
their application through governance79 systems and lifestyles, and the distinction
between wants and needs (Tamari, no date).
Good and bad discards80
The notion that discards are wasteful is closely linked to the assumption that most, if not
all, discards are either already dead or subsequently die as a result of the fishing activity.
However, many discarded animals survive, and live release of captured animals may
make a significant contribution to the sustainable use of fisheries resources. Guidelines
and criteria can be developed to identify “responsible” discarding. Examples of “good”
discards may include:
• species with a high probability of survival (e.g. crabs, starfish);
• species targeted for release (e.g. sharks, rays, swordfish, turtles, dolphins);
• live egg-bearing females (e.g. berried lobsters); and
• small pelagics slipped without stress, i.e. schools that have a high survival rate.
“Bad” discards may include all dead discards that had a potential commercial value
when alive, including juveniles of commercial species and endangered or threatened
species, which indicate undesirable fishing practices.
As discard practices also impact on biodiversity and energy transfers within
ecosystems, assessing the impact of discards in simple positive and negative terms may
prove difficult. It may be of more practical value to prepare additional guidelines on
best practices with regard to bycatch management on a fishery-by-fishery basis.
78 “... technical measures related to fish size, mesh size or gear, discards, closed seasons and areas and
zones reserved for selected fisheries, particularly artisanal fisheries, the establishment of mechanisms for
communicating information on areas of high concentration of juvenile fish, .... and support for studies
and research that will minimize bycatch of juvenile fish”.
79 A broader analysis of these issues is provided in FAO, 2001b.
80 “Again, the kingdom of heaven is like unto a net, that was cast into the sea, and gathered of every kind:
Which, when it was full, they drew to shore, and sat down, and gathered the good into vessels, but cast
the bad away”. Matthew 13: 47–48.

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There are major differences in discard policies and practices between regions,
between countries within a region and between fisheries within a country. National
policies and objectives (e.g. prioritizing food supply), markets, food preferences,
fishery economics and moral orientations all influence discard practices. In very broad
terms, countries can be classified into four groups, those that:
• promote selective fishing and bycatch and discard reduction or elimination –
mainly developed countries fishing mostly in temperate waters;
• pursue a strategy of full utilization of all components of the catch – these countries
include most of the Southeast Asian nations, China and Cuba;
• steer a middle course between advocating bycatch reduction and promoting full
utilization of the catch – these include the EU countries and many developing
nations;
• by the nature of their fisheries, do not have a significant “discards problem”.
These include countries with either a small or no industrial fishery (e.g. many
Pacific Islands and some Caribbean countries) and by default are “full utilization”
countries.
Acceptable level of discards
Assuming that discards are unavoidable, the question of an acceptable level of discards
has a moral dimension in addition to the more obvious biological and economic
criteria. No-discard policies are consistent with the ethical orientations cited above
and are addressed in more detail in Section 4.3.1. In the United States bycatch plan
(see Section 4.4.2), “concerns” regarding bycatch and discards are considered under
four indicators: (i) population concerns where discards contribute significantly to
the status of the fish population; (ii) social and economic concerns; (iii) ecological
concerns; and (iv) public concerns that are of particular relevance in the case of seals,
marine mammals, seabirds and other marine animals of an aesthetically high profile.
In practice, “acceptable” levels of discards are negotiated between interest groups with
little reference to morality.
4.2.3 Incidental catch and discards of charismatic and endangered species
The incidental catch of most of these species is discarded, either because of a legal
requirement or because of lack of commercial value. Endangered species are those
threatened with local or global extinction. Several species or species groups are
considered “charismatic” since certain societies accord their existence an additional
value for numerous reasons. There are long-standing cultural and religious ties with
some species such as dolphins and seabirds.81 Many feature in children’s stories or are
used in advertising, films and cartoons, which contribute to their enhanced status in
society.
Whatever the reason, society values these species and is willing to pay a price for
their preservation. These perceptions and values have a direct impact on fisheries, which
incidentally catch and discard these species, through changes in fishing techniques
(e.g. TEDs, Medina panels and pingers [acoustic deterrents]), and through trade (e.g.
through CITES and unilateral measures such as tuna, shrimp and shark imports to the
United States).
Assessing the impact of a fishery82 on marine mammal, seabird or turtle populations
poses several problems. There is a general shortage of information, e.g. in pelagic trawls
81 For example, the poem, “The Rime of the Ancient Mariner” by Samuel Taylor Coleridge (1789); frigate
birds on amulets in the Solomon Islands.
82 See Northridge, 1991; Perrin, Donovan and Barlow, 1994; and also the technical documents prepared for
recent International Whaling Commission (IWC) meetings.

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where the incidence of cetacean bycatch may be higher than previously estimated
(De Haan et al., 1998). Reliable information on incidental catches is generally only
available through observers. It is also difficult to assess population size (particularly for
marine mammals) and to assess the consequences of a relatively low and unpredictable
incidental catch rate. While over 2 million dolphins may be encircled by tuna purse
seiners in the Eastern Tropical Pacific, fewer than 3 000 are killed by the fishery as a
result of strict application of release procedures monitored by observers. However, the
failure of the dolphin stocks to recover may indicate additional indirect83 mortalities
caused by fishing activities and the effects of other factors are not well understood.
Information on incidental catches of manatees and dugongs is particularly scarce and
it is likely that these animals are consumed rather than discarded if caught by artisanal
fishers.
A number of NGO reports84 indicate that fishing activities cause substantial
mortalities of sea turtles. In contrast, at a recent FAO meeting85 representatives of certain
Asian fishing nations contested the level of turtle mortality resulting from longlines,
indicating that incidental turtle catches were rare and survival is apparently high since
most turtles are released alive. Trials of mitigation measures to avoid or reduce hooking
have not proved promising since the incidence of hooking is so low that field trials have
encountered difficulties in achieving statistically significant results.
Reliable current compilations (Brothers, Cooper and Løkkeborg, 1999) of global
information on the interaction between fisheries and charismatic species are relatively
scarce. This absence of a recognized (Gillespie, 2002) global database on incidental
catches of such species tends to result in argument and conflict over the impact of
fisheries, the effectiveness of mitigation measures and the impact of other factors
such as pollution or destruction of breeding grounds and nesting sites on endangered
populations.
Mitigation and conservation measures
Comprehensive legislation (FAO/UNEP, 1986) and numerous action plans86 for the
conservation of charismatic species exist at national and international levels. The
United States’ Marine Mammal Protection Act (MMPA) and Endangered Species Act
(ESA), and Australian legislation provide good examples. Release of live rajids, bluefin
tuna (United States and Canada) and other regulated species is mandatory in certain
fisheries. The United States has a ban on shark finning and a similar ban is coming
into force in the EU. Near real-time monitoring of discards and retention of incidental
catches for monitoring purposes is obligatory in certain United States fisheries.
Recent amendments87 to United States fisheries legislation calls for the Secretary of
State, in cooperation with the Secretary of Commerce, to seek an international agreement
to establish standards and measures for bycatch reduction that are comparable with
United States standards in any fishery regulated under the Magnuson-Stevens Act for
which an international agreement is necessary and appropriate.
A range of mitigation measures is in force throughout the world, for example:
• TEDs are in widespread use and mandatory in many fisheries;
83 Southwest Fisheries Science Center, 2002. Note that disease may also play a role in reducing some
dolphin populations in the Eastern Tropical Pacific.
84 Prepared for IUCN, the World Wide Fund for Nature (WWF), Pew Charitable Trusts and others.
85 FAO file note on informal meeting held during the Committee on Fisheries (COFI) XXV, Rome, 2003.
86 The Global Plan of Action for the Conservation, Management and Utilization of Marine Mammals was
developed between 1978 and 1983 jointly by UNEP and FAO and was endorsed by UNGA. UNEP is
to retool the Marine Mammal Action Plan in consultation with CMS, CITES, CBD, the regional seas
conventions and action plans and relevant partner organizations, including IUCN.
87 Magnuson–Stevens Fisheries Conservation and Management Act, Section 202 (h)(1), signed into law on
11 October 1996.

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• Australia is emphasizing the improvement of post-hooking handling and release
techniques for turtles to ensure greater survival;
• Australian longliners are undergoing trials with “capsules” and “chutes” to reduce
hooking of seabirds;
• seal saver devices (SSDs) have been developed in New Zealand’s squid fisheries;
• driftnets/gillnets are being replaced with longlines in cetacean bycatch
hotspots;88
• national and international sanctuaries have been established, e.g. the Irish Whale
and Dolphin Sanctuary and the Ligurian Sea Cetacean Sanctuary (Italy, Monaco
and France);
• pingers89 and interactive pingers (Amundin, Desportes and Goodson, 2002) are
under continued development and testing;
• there is increasing international monitoring and cooperation90 on identification of
whale migration routes and establishment of marine protected areas (MPAs),91 on
elimination or reduction of certain fishing activities, on enforcement mitigation
measures and on development of additional measures (Read, 2000);
• legislative provisions and other measures to avoid incidental capture of marine
mammals in tuna92 fisheries have been introduced.
Fishery managers, particularly those in developing countries, require: (i) a
framework93 for the introduction and acceptance of such measures by industry; (ii)
more specifically, advice on the design, operation and financing of incidental catch
monitoring; and (iii) assessments of the advantages and disadvantages of the different
mitigation measures.
Trade and economic impact of incidental catch
The incidental catch of charismatic and endangered species is having a growing
influence on fisheries and fish trade. Conservation activists and scientists have called
for the cessation of tuna longline fishing to protect turtles and for trawl bans to protect
corals and other benthos. Multinational companies are making purchases only from
fisheries that implement mitigation measures, and ecolabels are intended to promote
products from implementing fisheries. Trade disputes over mitigation measures
regarding incidental catches of turtles and dolphins have disrupted trade in shrimp94
and tuna respectively. Several important developments are likely to impact further on
fisheries and fish trade:
• the pending conclusion of a memorandum of understanding between FAO and
CITES clarifying the role of FAO in relation to fish and related species;
• a gradual move towards international consensus on ecolabelling in marine
products (Wessells et al., 2001);
88 See, for example, ASCOBANS Jastarnia Plan (Baltic harbour porpoise), ASCOBANS, 2002.
89 Concern has been expressed over the effects of pingers in: (i) excluding marine mammals from certain
habitats or zones; (ii) interference with migratory pathways; or (iii) long–term effects of aquatic noise.
90 ASCOBANS and ACCOBAMS were both adopted under the auspices of the 1979 Convention for
the Conservation of Migratory Species of Wild Animals (the “Bonn Convention”). There are similar
arrangements in other regional seas conventions. Annex II of the Barcelona Convention Protocol
Concerning Specially Protected Areas and Biological Diversity in the Mediterranean lists several marine
mammal species as “endangered or threatened“ and, as such, they are given special protection.
91 EC Habitats Directive (92/43/EEC). The network of Special Areas of Conservation (SAC) is called
Natura 2000.
92 For example, the EC ban on the use of driftnets longer than 2.5 km, adopted by the Community in
conformity with the UN resolution prohibiting the use of large pelagic driftnets (Council Regulation
[EEC], No. 345/92 of 27 January 1992), and the prohibition of “dolphin sets” (Council Regulation
[EEC], No. 3034/92 of 23 October 1992).
93 A description of such a framework is given by Broadhurst, 2000.
94 For example, World Trade Organization, 2001. The decision of the Appellate Body conditions market
access on the adoption of a programme ... comparable in effectiveness [with that of the United States].

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• technical advances in traceability95 of marine products that will facilitate
enforcement of mitigation measures; and
• civil actions by conservation organizations.
The action of conservation organizations in the United States is of particular note
in relation to bycatch and charismatic species and may be the precursor of other such
activities. Oceana,96 an NGO, requested the United States Department of Commerce
to rule on the interpretation of fisheries legislation, specifically the legislation that
requires the NMFS to “establish a program to count, cap and control bycatch in the
nation’s fisheries”. Pursuant to a United States court finding the NMFS in violation of
fisheries legislation (MSA), Oceana claimed that the NMFS had failed to apply national
legislation. In a comprehensive response (Federal Register, 2003), the NMFS was
effectively forced to set out such a programme and make financial and other provisions
for its implementation. In a second case, a coalition of conservation NGOs led by the
Earth Island Institute effectively blocked the United States administration’s attempts to
change the “dolphin safe” designation of certain tuna products, thereby pressuring for
a cessation in fishing for tuna on “dolphin schools”. Such trends are likely to expand
to other fishing and fish-consuming nations.
4.3 FISHERY MANAGEMENT ISSUES
The central “discard problem” for the fishery manager is to design a management
regime that meets multiple social, economic and biological objectives, while limiting
or preventing discarding (Hall, Alverson and Metuzals, 2000).
Impact of discards
Design of effective management regimes may require assessment of the biological,
ecological and economic impacts of discards. A parallel study97 has addressed this
question in some detail. Just as the quantity of discards is difficult to assess, it is
equally clear that it is even more difficult to assess their impact. Few relevant studies
exist, and it is not easy to disentangle the relative impacts of bycatch and discards. The
economic and social impacts are briefly discussed in Section 4.6.3. The causal diagrams
of discarding are presented as a means of structuring further studies on discards and
their impacts (see Annex C).
Management frameworks
The following sections address three different approaches to bycatch and discards:
• a “no-discard” policy with comments on its management approach;
• generic management measures and their advantages and disadvantages with
respect to discarding; and
• comprehensive approaches to bycatch and discards.
4.3.1 The “no-discard” regime
A number of countries98 pursue a “no-discard” policy99 and several prohibit discards at
sea under their legislation. A “no-discard” policy is consistent with best practice and
is likely to minimize discards in conformity with UNGA resolutions and the CCRF.
The following key points are noted:
95 For example, the EU’s tracefish project and the introduction of radio–frequency identification device
(RFID) tags in numerous products.
96 www.oceana.org
97 Poseidon Aquatic Resource Management Ltd, 2003. See also Horsten and Kirkegaard, 2002.
98 British Virgin Islands, Canada, the Comoros, Ecuador, Equatorial Guinea, Faeroe Islands, Iceland, the
Islamic Republic of Iran, Indonesia, India, Lithuania, Namibia, Nicaragua, Nigeria, Norway, Peru,
South Africa, Seychelles, United States and the United Republic of Tanzania.
99 Known as a “full retention policy” in the United States.

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• “no-discard” legislation may be enforced to varying degrees, and at times
selectively, in recognition of the unpredictable nature of fishing operations;
• effective discard bans are almost invariably supported by a range of other
complementary measures (see below);
• there is generally some allowance made to ensure that fisheries maintain their
economic performance or competitiveness;
• discard bans are more common in “clean” fisheries (i.e. fisheries with little non-
commercial bycatch);
• discard bans have widespread support among fishers if they are applied in a fair
and pragmatic manner;
• several countries that are recognized as leaders in fisheries management have a
“no-discard” policy; and
• most important, a “no-discard” policy implies a distinctly different approach to
the design of fisheries management measures when compared with a “minimize
discards” policy.
A “no-discard” policy changes the focus of management and fishery indicators
from landings to gross catches and from production to total fishing mortality. This is
exemplified in the contrasting Norwegian and EC legislation:100
• Norway: “it is prohibited to catch …”
• EC:101 “it is prohibited to have on board …”
This means that many of the Norwegian fisheries management measures are
designed to ensure that unwanted fish is not caught. Thus, the choice is not between
returning unwanted fish to the sea and obligatory landings for fishmeal or animal feed,
but between catching and not catching unwanted fish. These complementary measures
accompanying discard bans include:
• active rather than static management through close monitoring of fisheries and
rapid closures of areas with excessive quantities of unwanted bycatch;
• obligations on fishers to move fishing operations when encountering unwanted
bycatch;
• obligations to land all catches;
• no MLS and no (or reduced) benefits from landings of juvenile fish;
• usually a high level of observer coverage;
• bycatch quotas and closure of the fishery when the bycatch quota is reached;
• financially viable mechanisms for disposal of landings of unwanted bycatch (e.g.
fishmeal, Iceland’s “bycatch bank”, long-term price agreements, promotion of
markets for/products from unwanted bycatch, new product development and
presence of a “buyer of last resort”).
In Iceland fishers are allowed to land a certain proportion of undersized fish, which
is only partly deducted from quotas. Quotas are tradable, allowing fishers to purchase
them to cover unanticipated landings. A similar system exists in Norway whereby
fishers are allowed to substitute quotas in one species for quotas held in another in
accordance with predetermined ratios (Kelleher, 2001). The ratios are partly based on
the anticipated species composition ratios in the catch. This allows fishers to avoid
discards when encountering a species composition that does not meet the species
composition of their quota holdings.
100 “Last year a Danish skipper was caught with more than 40 percent of illegal fish in the hatch. To the
media the skipper says: ‘I was in the Norwegian zone and because of their discard ban, I had to keep
the fish on board’. As a reply, the Danish Ministry argues to us: ‘the skipper has no excuse for having
illegal catch onboard – he has to sail in Danish waters and dump the catch there’.” – K. B. Christensen,
Chairman of The Danish Society for a Living Sea (Web site).
101 The EU regulation prohibits “retention on board of fish which does not comply with the regulations”.
The EU may propose a legal ban on discarding from 2006 (European Commission, 2002a).

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A “no-discard” policy is precautionary since the “default scenario” is a ban on
discards. It is incumbent on a particular fishery to justify discards or show why they
are unavoidable. The legislation may then make an allowance for such unavoidable
discards, e.g. applied only to commercial species. The country’s development
programme can examine means of reducing the unwanted bycatch, develop alternative
fishing opportunities or finance the phasing out of such wasteful fishing technologies.
It is suggested that there is a fundamental difference between a “no-discard” approach
and a “minimize discards” approach. “Minimize discards” often merely endorses the
status quo by paying lip service to discard reduction. Policies and programmes that
seek to minimize discards often do not determine the target minima and there is little
consensus on how to determine an acceptable level of discards. Enforcement of discard
regulations is likely to encounter the same practical problems whether the regulations
are designed to prevent or to minimize discards. However, the ethical interpretation,
management philosophy, regulatory framework and design and application of measures
are substantially different in the “no-discard” approach. This approach would benefit
from a detailed appraisal in terms of its impact on resources and broader application
in other fisheries. For example, many fishers in the United Kingdom are opposed to a
“no-discard” regime, regarding it as unworkable and claiming, with some justification,
that discards are unavoidable (Agricultural Economics Research Institute, 2000).
Further analysis of the rationale behind such views may be of value in seeking effective
management approaches.
4.3.2 Implications of generic fishery regulations on discards
Many generic fishery regulations may promote discards or do little to minimize or
eliminate them. As discard practices are determined by a wide range of factors, it is
difficult to attribute changes in these practices to a given regulation or set of regulations.
Fishery managers often face a regulatory dilemma since regulations designed to protect
one species may increase bycatch or discards of another. The groundfish fisheries of
Alaska provide a history of different regulatory approaches to discard practices.
Effort control
Overfishing often contributes to discards since declining average sizes tend to make
the catch less marketable. A reduction of fishing effort (e.g. through fleet capacity
reduction, closed seasons, days-at-sea programmes) can make a significant impact on
discard practices.
Minimum landing size (MLS)
MLS regulations102 almost invariably promote discards since MLS is difficult to
harmonize with the selectivity of the fishing gear, particularly in multispecies fisheries.
In these fisheries different sizes and shapes of fish are likely to have a wide range of
MLS, often determined as a function of the size at first maturity of each species, rather
than as a function of the gear selectivity. A recent change in MLS in the North Sea
simply “legalized” the previous discards of juvenile plaice caught in the trawl fishery
targeting sole. In fisheries where there is a high discard survival rate (e.g. lobster), MLS
regulations are important. When increased recruitment results in large year classes of
juvenile fish, discards may increase if MLS regulations are applied. MLS regulations
are often applied only at landing sites and not at retail markets or restaurants (which,
for example, commonly serve undersized fish, including fish larvae and lobster). MLS
regulations may also conflict with obligations to land bycatch.
102 “... the only practicable method of checking the depletion of the North Sea fishing grounds and enabling
the fish supply to recover is by legislation based on the principle of the size limit” (Holt, 1895).

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Minimum mesh size (MMS)
MMS is closely linked to MLS. Increasing MLS without accompanying increase in mesh
size will only increase discards. Several countries show inconsistencies between MMS,
MLS and size at first maturity of the target species. Mesh alone does not determine
selectivity of the net and hanging parameters may be equally important. Rigging of
the fishing gear, and trawl gear in particular, exerts a major impact on selectivity and
can entirely undermine mesh size regulations. Many jurisdictions lack trawl rigging
regulations to complement those of trawl mesh size. This demonstrates poor awareness
of such impacts or possible difficulties in framing and enforcing appropriate regulations.
Codend mesh size is difficult to enforce without observers and costly sea inspection.
Regulations limiting a vessel to carrying nets of one mesh size may encounter strong
opposition by fishers who target different species on different grounds during the same
trip. An increased mesh size may not reduce discards since 100 percent of many species
are discarded (Allain, Biseau and Kergoat, 2003) and selectivity of gear may be highly
variable in relation to the discarded species. Square mesh panels are obligatory in many
fisheries.
Composition of landings
Senegal requires shrimp trawlers to land a minimum of 15 percent shrimp to retain a
shrimp licence, thereby creating an incentive to discard. French dredgers keep worthless
species on board merely to comply with the percentage regulations. Such regulations
may be difficult to enforce effectively, particularly when weights have to be calculated
as live-weight equivalent, as set out in the EC regulation.103 However, although such
measures have an economic cost, in the case of obligations placed on tropical shrimp
trawlers to land bycatch, there is some evidence that these regulations reduce discards.
Local landings of bycatch from distant water fishing vessels licensed to fish in coastal
state waters may be considered an import by the coastal state and subject to import
tariffs that render bycatch landings unprofitable.
Seasonal closures and time restrictions
These are common and useful measures, which reduce mortalities and discards of
juveniles (Adlerstein and Trumble, 1998). Several Australian prawn trawl fisheries only
open when the prawns have reached a certain size (e.g. Spencer Gulf, South Australia).
Time restrictions are applied in varying levels of detail. For example, if hake comprises
more than 10 percent of landings in Argentine fisheries that do not target hake, then
vessels are required to stay in port for 48–96 hours. Certain vessels are required to fish
south of 48ºS and remain in harbour for 120 hours between trips.
Closed areas and area controls
These are usually general, rather than discard-specific measures. Closed areas are
normally established to protect juveniles,104 spawning grounds or areas of special
biological interest (e.g. coral reefs, Posidonia beds). Area restrictions include the creation
of marine parks, areas reserved for traditional fishing activities and areas where certain
gears are prohibited (e.g. no-trawl areas). Closed areas are likely to be of particular
use in countries that pursue a “full catch utilization” strategy (e.g. in Southeast Asia).
103 It is illegal to land more than a certain percentage of cod and haddock when using a mesh size <100 mm
(Council Regulation [EC], 1998).
104 In European waters the Norway pout Box protects juvenile haddock to the east of Shetland; the Plaice
Box restricts fishing to smaller vessels and is intended to protect juvenile plaice and sole. In the Mackerel
Box, purse seining is prohibited to protect juvenile mackerel.

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Obligatory change of fishing area is a common complementary measure105 under “no-
discard” regimes.
High catches of unwanted fish may trigger area closures in some fisheries. Norway
enforces an active closure scheme to protect juvenile cod in the Barents Sea, i.e. the
closed areas change in relation to the distribution of the undesirable bycatch of
juveniles. The closures are determined according to the percentage of juveniles in
the catch, based on combined information from research cruises, observer reports
and monitoring of chartered commercial trawlers. Australia’s northern prawn fishery
provides another example of “active closures” to avoid catches of juvenile prawns,
while the Gulf of Maine fisheries also make extensive use of area closures and “rolling
closures” to protect juveniles or marine mammals. While these active closures have the
advantage of responding to the current conditions on the fishing grounds, the costs
of administering such regimes can be high. In the BSAI/GOA groundfish fisheries
information on bycatch is rapidly collated and disseminated to enable vessels to avoid
areas with high bycatch or, if necessary, close certain fishing grounds.
Fish handling
EU pelagic freezer vessels may be prohibited from installing graders or must install
automatic sorting machinery so that fish “cannot be easily thrown back into the sea”.
Under Australia’s Sub-Antarctic Fishery bycatch action plan, the discharge of dead
fish, fish offal or by-products of fish processing is not permitted in order to minimize
feed opportunities for seabirds and marine mammals. Offal and retained bycatch are
turned into fishmeal and stored on board. The release of unwanted live fish, crabs,
tagged live fish, skates and large sharks is permitted.
Operation of the gear
In addition to obligations to use TEDs and BRDs, gear restrictions include mesh
size and hook size limits, specification of longlines hook type and leader material
and requirements for escape panels in traps. Extensive and detailed records of gear
alterations may be required in some fisheries. Regulations106 governing the operation
of gear may be difficult to enforce.
Quota regulation and discards
A number of studies107 have addressed the issue of whether quotas, and individual
transferable quotas (ITQs) in particular, foster discarding. The regulatory framework
is but one factor determining discards and the quota regulations may not be the most
important regulatory cause of discards in a given fishery (e.g. MLS regulations may be
more important). Building flexibility108 and allowing quota transfers may help reduce
105 For example, the Australia Sub–Antarctic Bycatch Action Plan (BCAP): where any haul contains more
than 100 kg of mackerel icefish, and more than 10 percent of the icefish by number are smaller than
240 mm total length, the fishing vessel shall move to another fishing location at least five nautical miles
distant. The fishing vessel shall not return to any point within five nautical miles of the location where
the catch of small icefish exceeded 10 percent for a period of five days. If, in the course of fishing, the
bycatch in any one haul of any species for which bycatch limitations apply is equal to or greater than
two tonnes, the fishing vessel shall not fish using that method of fishing at any point within five nautical
miles of the location where the bycatch exceeded two tonnes for a period of at least five days (Australian
Fisheries Management Authority, 2003). Similar regulations apply in the NAFO area. See NAFO/FC
Document 02/9, Serial No. 4624.
106 For example, in the Northeast Pacific midwater trawls must be kept off the bottom when the bottom
trawl fishery is closed.
107 Numerous studies have addressed this issue, inter alia: Copes, 1986b; Arnason, 1995, 1996; Pascoe,
1997.
108 For example, some Norwegian fisheries allow individual fishers to substitute their quota in species A
with quota in species B at predetermined ratios of substitution.

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discards resulting from quotas. While many EU fisheries do not operate under formal
ITQ systems, there is little doubt that the regulatory discards resulting from the EU’s
quota system is a major cause of discards in many EU fisheries. Trip limits may also
cause discards of legal-sized fish.
Bycatch quotas
Bycatch quotas109 exist in many fisheries (e.g. South Africa, United States, New
Zealand). Under the United States Sustainable Fisheries Act, allocations of regulatory
discards may be transferred to individual fishing vessels as an incentive to reduce per
vessel bycatch and bycatch rates in a fishery, provided that “(i) such allocations may
not be transferred for monetary consideration and are made only on an annual basis;
and (ii) any such conservation and management measures will ... result in an actual
reduction in regulatory discards in the fishery” (see Annex A.6.1 for further details of
the Alaskan arrangements).
Observer programmes
Seagoing observers are crucial for monitoring discards. Observers normally have a
range of monitoring functions (and possibly an enforcement role), and monitoring
of discards may not be a priority function. Training and skills of observers vary
widely, as do the quality of observer reports and the use made of them. The presence
of observers may influence discarding practices, particularly if the observer role is
to report infringements of regulations. The low cost of observers makes them an
important tool for monitoring in developing countries. The EU has a particularly low
level of observer coverage, while there is increasing public pressure for a high level of
observer coverage in North American fisheries (e.g. the Oceana petition). Monitoring
of discards is an essential observer function in the United States Northeast Pacific
groundfish fisheries.
4.4 BYCATCH AND DISCARD MANAGEMENT FRAMEWORKS
Comprehensive bycatch and discard management frameworks are in place in several
countries and fisheries. In contrast to the bycatch/discard reduction strategies
described below, fisheries development and management plans in Southeast Asia focus
on bycatch utilization and value added.
CCAMLR
CCAMLR has adopted an ecosystem approach to fisheries management and provides
a comprehensive framework of management measures, many of which address bycatch
and discard issues. The measures (CCAMLR, 2002b) directly related to bycatch and
discards can be grouped as follows: reporting, gear regulations, bycatch limits, area
and time restrictions, and mitigation measures (primarily directed at reducing seabird
mortalities). The comprehensive CCAMLR framework is reflected in several other
fishery management regimes, in particular in those countries where incidental catches
of endangered species have attracted a high level of public awareness. NAFO and
ICCAT are among the other regional fisheries management organizations that have
established discard databases.
4.4.1 Australia: bycatch policy and action plans
Discard problems are subsumed under Australia’s bycatch policy and action plans.
Central to the policy is a recognition that bycatch is a resource, environmental,
109 The PFMC sets the discard rate at 16 percent for major species (range 5–20 percent). See the NPFMC
Web site for regulations concerning numerous other bycatch reduction measures.

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educational, engineering and economic issue and needs to be addressed strategically
and in a focused, coordinated manner.
The policy recognizes that there will be different requirements for addressing the
bycatch issue in different fisheries. AFMA coordinates the efforts of various interest
groups to develop fishery-specific bycatch action plans by establishing bycatch action
plan working groups consisting of scientific, industry, government and conservation
members. All 21 Commonwealth fisheries are required to prepare bycatch action plans
to reduce the impacts of fishing on non-target species. The plans are in various stages
of preparation, approval and implementation and cover a wide variety of fisheries
including shrimp trawl, fish trawl, scallop, longline and tuna fisheries.
Bycatch action plans identify the specific bycatch issues in a fishery and detail
actions required to address these issues. The bycatch action plan is then integrated into
the management arrangements for the fishery to enable the actions to be implemented.
Once completed, bycatch action plans will be reviewed annually in line with
Commonwealth policy.
4.4.2 United States: managing the nation’s bycatch
The Magnuson–Stevens Fisheries Conservation and Management Act (FCMA), which
is the principal United States fisheries management instrument, requires that bycatch
be avoided or, where it cannot be avoided, that mortality be minimized. There are some
differences between this and other major laws. The Marine Mammal Protection Act
(MMPA) and the Endangered Species Act (ESA) require zero mortality rates while the
Magnuson–Stevens Act indicates a reduction in bycatch “to the extent practicable”.
BOX 2
Guiding principles in Australia’s bycatch policy
An overarching objective of the policy is to ensure that bycatch species and populations are
maintained at sustainable levels. Within this are the following sub-objectives:
• reduce bycatch;
• improve protection for vulnerable/threatened species;
• minimize adverse impacts of fishing on the aquatic environment.
All decisions and actions to address bycatch will:
• foster stewardship of Australia’s aquatic resource, i.e. maintain and improve the quality, diversity
and availability of fisheries resources, including fish habitats, and the integrity of the aquatic
ecosystem into the future;
• promote cooperative and transparent approaches involving all stakeholders for effective
stewardship of our aquatic resources;
• integrate short-term considerations with long-term goals in managing aquatic resources;
• use robust and practical methods to assess bycatch so as to make decisions on management;
• recognize the unique biological, economic, cultural and social nature of individual fisheries;
• encourage cooperation in the development of complementary and effective arrangements among
relevant authorities where stocks overlap, are split between jurisdictions or are migratory;
• ensure the widest adoption of bycatch mitigation measures through collaboration between the
commercial, recreational, charter and indigenous fishing sectors, research and research funding
organizations, environment and nature conservation agencies and fisheries management agencies;
and
• apply a precautionary approach to the management of fish and aquatic resources.
Australian Fisheries Management Authority (AFMA)

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Federal fisheries operate under fishery management plans (FMPs), which must
contain management provisions to eliminate or reduce bycatch of all kinds. Under
the Sustainable Fisheries Act (SFA) and as an integral part of each FMP, the fishery
management councils (FMCs) were required to:
• standardize reporting methods to assess the amount and type of bycatch in
managed fisheries;
• adopt conservation measures that minimize bycatch through avoidance; and
• minimize the mortality of bycatch that cannot be avoided.
4.4.3 European Union: Community action plan to reduce discards of fish
By virtue of the heavy reliance on quota systems in the Common Fisheries Policy
(CFP) on conservation, discards in the EU are relatively high. Declining quotas
and stocks result in significant discards of commercially valuable fish as a result of
highgrading and quota limits.
There is widespread recognition of “the discards problem” among fishers and
administrators. Numerous studies by the EC and ICES have not adequately quantified
discards in the EU, partly because of weak discard sampling and observer coverage.
Several closed areas or boxes exist to protect juveniles. Bycatch and discard reduction
relies heavily on technical measures, which are difficult to enforce. The preparation
of production plans by producer organizations as provided under the CFP’s markets
policy may also provide an indirect entry point for discard management.
EU policy and practice on discards are substantially in arrears of the United States
and Australia as illustrated by the preliminary nature of the recent “Communication
from the Commission to the Council and the European Parliament” (European
Commission, 2002a).
BOX 3
United States – Managing the nation’s bycatch
“The fundamental national goal of NMFS’ bycatch-related activities is to implement conservation
and management measures for living marine resources that will minimize, to the extent practicable,
bycatch and the mortality of bycatch that cannot be avoided. Inherent in this goal is the need to avoid
bycatch, rather than create new ways to use bycatch.”
To accomplish these objectives, the report on Managing the nation’s bycatch (NMFS/NOAA,
1998a) made recommendations in the following areas:
• bycatch monitoring and data collection programmes;
• research on the population, ecosystem and socio-economic effects of bycatch;
• research to increase the selectivity of fishing gear and increase the survival of fish and protected
species that are inadvertently encountered by fishing gear;
• incentive programmes for fishers to improve bycatch performance;
• analysis of the implications of conservation and management measures for bycatch; and
• exchange of information and development of cooperative management approaches.
Steps to be taken:
• determine the quality of information on the magnitude of bycatch;
• evaluate the impacts of current bycatch practices on populations, fisheries and ecosystems;
• evaluate the effectiveness of current bycatch management measures;
• identify potential management alternatives;
• evaluate the population, ecosystem and socio-economic effects of each alternative;
• choose and implement an alternative; and
• evaluate the effectiveness of the implemented measures.

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4.4.4 Private sector initiatives
Numerous authors have stressed the need for fisheries administration and researchers
to work closely with the fishing industry (fishers, fishing companies, product
developers, gear specialists) on bycatch and discard management. A variety of private
sector initiatives exist. In Australia there has been close collaboration with industry in
the gradual introduction of BRDs. Essentially similar approaches have been pursued in
the New Zealand hoki fishery and the Alaska pollock fishery in the Northwest Pacific
(see Annex A.6).
4.4.5 Planning framework
A comprehensive and structured approach to discards and bycatch is required. It
implies a clear statement of policy with regard to discards, a description of strategies
and an implementation plan. Ideally, the discard/bycatch plan(s) would be an integral
component of fishery management plans. Southeast Asian countries have held
discussions on discards and formulated an action plan to reduce unwanted catch in the
region (SEAFDEC, 2003).
Monitoring of bycatch and discards needs to be an integral part of the fishery
research component of the management plan. A clear understanding of discard patterns
is required. Factors such as light intensity, tides, gear rigging and skipper habits all
affect the discard pattern (Catchpole, Gray and Frid, 2002). Education and awareness
have been shown to be an essential part of the discard management process. Similarly,
stakeholder involvement is crucial (Lart, 2002), in particular with regard to initiatives
to introduce gear modifications or regulatory measures. The effects of measures to
reduce bycatch and discards must be clearly demonstrated and the costs of changes
distributed equitably.
4.5 BIOLOGICAL AND ECOLOGICAL ISSUES
The provision of scientific advice relies on an accurate understanding of the state of
fish stocks. Discard information is included in few110 stock assessments partly because
BOX 4
European Union – On a community action plan to reduce discards of fish
“… the Commission will come forward with regulatory measures to reduce catches of younger fish,
bycatches in mixed fisheries and discards.1 Such measures will include:
• the introduction of more selective fishing gear, such as nets with larger meshes;
• square mesh panels, separator grids and changes in design and rigging of such gear in order to
improve selectivity;
• restrictions on fishing to protect juvenile fish, sensitive non-target species and habitats;
• minimum landing sizes in line with the selectivity of the gear concerned;
• ‘discard ban trials’ in which representative samples of fishing vessels would be encouraged by
economic incentives to retain their entire catch;
• the targeting of economic incentives for the use of more selective fishing practices;
• a voluntary code of conduct intended to reduce discarding;
• scientific and technical monitoring of fishing practices that result in discarding.”
A/RES/57/142
1 Extracted from European Commission, 2002a. See also European Commission, 2002c.
110 Baltic stocks, North Sea haddock, northern hake (ICES) and some United States stocks are examples.

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of the lack of adequate discard information. This omission may lead to inaccurate
conclusions or substantial differences between assessments (Casey, 1996). However, if
large, highly diverse fishing fleets are being sampled by a small handful of observers
faced with many practical difficulties, there is a risk that stock assessments will
be made less, rather than more accurate by the addition of the resulting raised
estimates of discards.111 Questions associated with discard sampling and raising of
discard estimates are addressed in Annex C.
4.5.1 Selective fishing, discards and the ecosystem approach
Promoting more selective fishing is one of two principal approaches to discard
reduction. Fisher behaviour and fishing gears are by nature selective. Fishers do not
want to catch fish that cannot be sold or that create sorting difficulties. Typically,
demersal trawling is considered to be at the less selective end of a range of fishing
activities while handlining is at the more selective end. Fishing activities such as
trawling, which cause mortalities across many trophic levels, marine communities or
species groups, are more likely to generate discards. However, selective fishing is more
likely to alter the balance of species in the ecosystem and across the trophic levels. In
the absence of an empirical framework for valuation of species and biodiversity, value
judgements may be necessary to resolve apparent inconsistencies between advocating
more selective fishing and the “ecosystem approach”.
4.5.2 Discard survival
Determination of the survival of discards is important:
• where discard information may be used in stock assessments;
• to assess ecological impact of discards; and
• to assist in designing mitigation measures, including the design of the fishing gear,
the use of the gear and the sorting and handling of catch.
BOX 5
Generic framework for a bycatch/discard management plan
1. Acquire information on bycatch and discards.
• Determine magnitude of discards – observer programmes are usually indispensable.
• Assess impacts (biological, social and economic) with a focus on major undesirable impacts.
• Establish the spatial and temporal patterns and particularly the capability of fishers to control
levels of unwanted bycatch.
2. Formulate bycatch/discard management policies and objectives as an integral part of a fishery
management plan.
• Account for the imputed costs of discards in the economic management framework of the
fishery.
3. Measures.
• Review/evaluate effectiveness of existing measures.
• Identify/evaluate alternative measures.
4. Decision framework and evaluation.
• Create decision framework/criteria in association with stakeholders.
• Decide/implement new measures. Monitor effectiveness and review impact.
111 ICES, 2002. See also ICES, 1985. There is a difference between short– and long–term stock assessments
particularly if discarding is variable. If age–based stock assessment is not carried out then discard
information may be of little or no value for stock assessment.

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A wide range of studies112 have been made on discard survival and a number of clear
relationships are well recognized.
• In trawl113 fisheries, survival is related to the duration and depth of the haul, the
type of bottom substrate and the species involved.
• Soak time, location and shape of the hook have a significant influence in longline
and gillnet fisheries.
• Finfish with air bladders that expand as they are hauled to the surface have a low
survival.
• Crustacean survival largely depends on the extent of the physical damage caused
by the fishing and sorting activities (Wassenberg and Hill, 1989). Discards of
benthic crustacea and molluscs tend to have a higher survival if discarded in the
location in which they are caught.
• Fish released from sport fishing have a high survival rate.
• Post discard mortality through predation may be important.
4.5.3 Ecological impacts
Many of the ecological impacts114 of discards remain unquantified. The combined impact
of the trawl damage to benthos and of discards may have a positive impact on the growth
of target species through an energy shunt along the food chain or fertilizing unproductive
sea floor (Rijnsdorp and van Beek, 1991). Evidence suggests that benthic discards are
rapidly reassimilated into the food chain (Groenewold and Fonds, 2000). The physical
presence of decomposing discard materials, together with downcurrent odour trails, may
lead to avoidance of the area and localized anaerobic conditions (Chapman, 1981).
A number of studies (Camphuysen et al., 1995) in European waters have shown
that discards are a major food source for seabirds115 (approximately 18 percent of 600
000 total food requirement were discards) in the North Sea. Overall consumption rates
were estimated at 95 percent for offal, 80 percent for roundfish, 20 percent for flatfish
and 6 percent for benthic invertebrates. The mass of discards eaten, including offal, was
estimated to be more than the amount of live fish (265 000 tonnes) taken by seabirds.
Thus the discards support substantial bird populations, which further prey on fish.
The impact of discards on biodiversity is not well understood. Isolating the effect
of discarding from other effects of fishing is difficult (Lindeboom and de Groot, 1998;
ICES, 2000d). The measurement of discards at the species level and quantification of
survival of the species present problems. As previously noted, reports also tend to
lump together the discards of unknown numbers of finfish116 and invertebrates. In
general, discarding is likely to favour scavengers.
4.6 TECHNICAL AND ECONOMIC ISSUES
4.6.1 Bycatch utilization
Bycatch utilization has been addressed in a series of FAO reports, which make
numerous recommendations that are not detailed in this publication (FAO, 1997;
FAO/DFID, 1998; FAO/UNDP/Government of Madagascar, 1995).
112 For example, a study on the Great Barrier Reef showed that 98 percent of discarded finfish and
cephalopods die. Approximately 12 percent of crabs, bivalves and echinoderms survived, thereby
considerably altering the proportions of the phyla and species in the benthic biomass. There was a
tenfold increase in crested tern populations caused by scavenging on the floating discards (Hill and
Wassenberg, 2000). For further details see ICES, 2000c; Davis, 2002; Mesnil, 1996.
113 Survival of fish passing through square mesh panels on top of the net is up to 65 and 90 percent for
Scottish Nephrops and demersal fishing respectively.
114 A separate FAO study addresses the ecological aspects of discarding (Poseidon Aquatic Resource
Management Ltd, 2003). See also FAO, 2001a.
115 “When seagulls follow trawlers, it is because they know sardines will be thrown into the sea.” Eric
Cantona cited by Cook, 2001.
116 Sharks and seahorses are among the exceptions.

Discards in the world’s marine fisheries – an update
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Issues 71
Tropical shrimp trawl fisheries face a particular range of difficulties. Vessels
are often small and have little room for bycatch.117 Landing large volumes may
undermine the price of bycatch and prices for artisanal producers. Collection at sea
must be highly cost effective and processing and distribution must be simple and
inexpensive to avail of limited purchasing power. Legal restrictions on transhipment
must be removed. Collectors may require medical certificates (to comply with shrimp
export requirements). Arrangements for crew compensation and avoidance of shrimp
contamination are required. Creation of bycatch collector associations and codes of
practice may be needed to avoid theft of shrimp and to conclude agreements with vessel
owners. Radio communication systems may also be necessary.
Experiences from Latin America, India and Africa indicate that stable arrangements
for at-sea collection of bycatch in tropical shrimp fisheries can be developed through
broad-based commercial agreements between groups of bycatch collectors and the
fishing companies; through provision of credit; and through support for processing,
marketing and distribution facilities.
4.6.2 Gear technology and selectivity
Gear technology and selectivity are specialized subjects and are not addressed in any
detail here. A wide range of developments continue to have a significant impact on
bycatch and consequently on discarding.
• Longlines: hook selectivity,118 restrictions on wire traces and minimum lengths of
longline gudgeons to reduce unwanted shark bycatch or to increase survival rates;
night setting; appropriate deck lighting to reduce bird attraction; disposal of offal;
use of streamers, weights and line shooters for underwater setting; examination of
the relationship between propeller rotation and line sinking.
• Biodegradable escape panels in pots (Alaska) to prevent ghost fishing.
• Halibut excluder devices in pot fisheries (Alaska).
• Fish behaviour studies to identify fish electronically prior to catching in the
trawl.119
• Use of multiple rig trawls likely to reduce cod bycatch in industrial fisheries
(Denmark).120
• Flexible grids121 built into trawl nets to pass through rollers (approved for
Norwegian waters).
• Turtle excluder devices (TEDs) in many industrial shrimp fisheries.
• Bycatch reduction devices (BRDs), particularly in the Gulf of Mexico and
Australian trawl fisheries and in the Argentine hake and shrimp fisheries.
• Use of square mesh panels in Nephrops fisheries.
• Regulation of soak times for gillnets.
The gear technology per se is not necessarily the limiting factor in discard and
bycatch reduction. The economic consequences of introducing gear modifications122
are possibly the single most important constraint. This further emphasizes the need for
a close partnership with industry in the introduction of BRDs and more selective gears
117 See Kungsuwan, no date, for a discussion of vessel design.
118 “Small hooks catch a large proportion of large fish, and large hooks a considerable proportion of small
fish.” Cunningham, 1896.
119 In order to distinguish between small pelagics (some are low quota) that look identical on shipboard
electronics (Triple Nine, an Esbjerg [Denmark] fishmeal company).
120 Using eight trawls on five warps bycatch of cod was “practically none” in the North Sea prawn trawls
(Fishing News International, 42, of 9 September 2003).
121 The use of grids in shrimp trawl fisheries is relatively widespread. Their use in finfish trawl fisheries is
less common but used inter alia in Argentina, the Faeroe Islands, Greenland, Canada, Iceland, Norway,
the Russian Federation and Sweden (data from 1998).
122 Gear definitions can be problematic. “… shall be prohibited to use any demersals trawl …or towed gear
…, gillnet or similar static gear incorporating hooks …”. Council Regulation (EC), 2002.

Discards in the world’s marine fisheries – an update
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Issues 71
in a gradual and adaptive manner. Because of the steep slope of the selectivity curve
of bottom trawl mesh, increases in mesh size are not likely to have major impacts on
discard levels.
Studies123 on BRDs for the Gulf of Mexico shrimp fishery (primarily intended to
reduce mortality of juvenile snapper and related species), showed that an increase in
finfish biomass as a result of the BRDs could result in an increase (up to 4 percent), or a
decrease (up to 17 percent) in shrimp biomass. A linear relationship between predation
and shrimp biomass was developed. The protocols developed for testing of TEDs and
BRDs provide a useful model for such work in similar fisheries.
In some fisheries the introduction of BRDs including square mesh panels has been
industry driven by the need to exclude jellyfish, reduce discards of target species,
comply with trade practices regarding turtles or reduce the costs of sorting fish.
A BRD technology clearinghouse or network of expert resources would be of value.
In addition to the technical aspects of BRDs associated fish behaviour studies, the
clearinghouse could establish guidelines for the introduction and acceptance of BRDs
by fishers. Advice on framing and application of the required regulations would also
be valuable. FAO is currently preparing technical guidelines on bycatch reduction in
shrimp trawl fisheries.
4.6.3 Economic issues
Two sets of economic issues arise in relation to discards:
• the costs associated with discards at the level of the fisher, the fisheries authorities
and society in general; and
• the use of economic measures to reduce discards.
BOX 6
Mesh size and minimum landing size1
In 2001 technical regulations in the heavily overfished Baltic cod fishery were revised by the IBSFC
on the basis of scientifically solid international research. However, managers refused to follow the
recommendations of “a one net rule”, likewise a harmonizing of selectivity and MLS. Thus the
minimum landing size of 35 cm was maintained (subsequently increased to 38 cm) but the minimum
mesh of traditional diamond mesh codend was increased from 120 to 130 mm and then to 140 mm in
polyethylene codends and to 125 mm in polyamide codends.
The amendments of the fishing rules did not merely fail to meet their objectives. They made
the situation even worse. The length distribution of annual landed trawl catch remained unchanged
despite the increase in minimum mesh size until the MLS was increased in January 2003 to 38 cm.
Because no change in the selectivity of the widely used traditional diamond mesh codend was made,
all fish between 35 and 38 cm were now undersized and consequently discarded. Thus it was the
MLS and not the mesh size that determined which part of the catch was landed, indicating that the
objective of increased selectivity had gone terribly wrong.
Swedish fisheries observers on board estimated that in January 2003, on average, 34 percent of
trawl catches consisted of undersized cod and in April 2003 this devastating waste of resources forced
the EC to stop the trawl fishery in EU waters.
1 Adapted from Valentinsson and Tschernij, 2003.
123 Modelling studies tested several predator/prey relationship scenarios. For a summary see NMFS/
NOAA, 1998b; Robins, Campbell and McGilvray, 1999.

Discards in the world’s marine fisheries – an update
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Issues 73
Costs and benefits to fishers
At the level of the fisher, the act of discarding involves an economic decision, usually
of a short-term nature (day/trip/season). The fisher weighs the costs and benefits of a
wide range of factors such as the following:
Cost factors
• Value/amount of hold space/freezer capacity
• Cost of sorting and crew share
• Cost of freezing/catch preservation
• Weather and composition of future catch
• Landing costs/taxes
Benefits/losses
• Price of fish/bycatch
• Loss of quality in target catch
• Bycatch quota (if existing)
Of particular interest are schemes for special compensation for crews regarding
retention of species with marginal value, which might otherwise be discarded. Bycatch
in tropical shrimp fisheries is often considered the “property” of the crew, although
vessel operators may discourage bycatch retention because of loss of shrimp quality or
fears of theft of shrimp through transhipment at sea.
Regulations on discards and incidental catch force fishers to adapt their fishing
techniques and operations with possible loss of efficiency and returns. Discards have
had a major economic impact in the Alaska groundfish fishery. Operators are obliged
to discard Pacific halibut, which is managed under a separate regime (International
Pacific Halibut Commission [IPHC]). When the halibut discard quota is filled, the
fishery may close or move to less profitable fishing areas, resulting in major economic
losses (Trumble, 1996). Fishers will assess the costs, potential losses124 and possible
benefits associated with the use of BRDs or other measures designed to reduce discards
or bycatch, e.g. BRDs introduced in New South Wales resulted in a decline of 90
percent in discards and employment of one less crew per vessel. The economic impact
of incidental catch and discards on trade has already been noted.
Costs to the administration
The costs of monitoring and control can be substantial. In the United States the costs
associated with enforcement of the Marine Mammal Protection Act and Endangered
Species Act alone account for over 10 percent of total monitoring, control and
surveillance costs. Observer programmes and efforts to acquire discard information
for stock assessment may also involve significant costs.
Costs to society
Few comprehensive studies have been carried out on the cost of discards to society
and on who bears such costs. The costs to society of losses of charismatic species or
of ecosystem change resulting from discards (which could be positive) have not been
identified. Assessment of the costs of discarding and the costs and benefits of measures
relating to bycatch and discards will help in designing appropriate management
programmes.
One of the most detailed studies on the estimated costs of discards was carried out
in the North Sea. The study estimated that approximately 15 000 tonnes of landings
124 Substantial financial losses can be incurred by the introduction of square mesh panels. See Rommel and
Napier, 1999.

Discards in the world’s marine fisheries – an update
72
Issues 73
of plaice, sole, cod and whiting were foregone as a result of discards in the North
Sea Crangon fishery (Revill et al., 1999). These foregone landings were valued at
25.7 million euros. The estimated annual cost of discarding in three EU case studies
varied from approximately 70 percent of total annual landed value in the Netherlands
case to 42 percent in the United Kingdom whitefish case and 43 percent in the French
Nephrops case (Nautilus Consultants, 2001). These studies focused on costs related to
commercial species and did not address the more complex questions of costs associated
with the ecosystem impact of discards.
In 1994, all BSAI groundfish fisheries discarded an aggregate total of 162 161 tonnes
of allocated groundfish species for which a total allowable catch had been set. The
opportunity cost of these discards exceeded US$92 million. The total retained catch
of all groundfish species in these fisheries was just over 1 699 500 tonnes with a value
in excess of $925 million. Thus, the ratio of the value of retained catch to discards
(retained/discard value ratio), weighted by fishery across all BSAI groundfish fisheries,
was 10:1. That is, for each dollar of bycatch “opportunity cost” imposed, $10.10 of
output was produced from retained catch. Individual rates varied from a high of $29.2
in the pollock target fishery, to a low of $2.4 in the “other” groundfish target fishery.
Discarding was estimated to have a social cost of $25 million per annum in the southern
New England yellowtail flounder trawl fishery (1998–1994 period).
In contrast, the use of BRDs to reduce mortalities in the red snapper fishery was
estimated to incur losses of $117 million in the shrimp fishery (NMFS, 1998). The costs
of discards may be shifted. The Gulf of Mexico shrimp fishery discarded significant
quantities of juvenile snapper, thereby depleting snapper stocks. The shrimp fishery
has had to absorb the costs of snapper bycatch reduction, although the costs to the
shrimp fishery may surpass the economic value of the snapper fishery.
Conflicts
Discards are a common source of conflict between artisanal and industrial fishers,
particularly when large quantities of discarded fish are seen floating at sea or rotting
on beaches. Apart from the waste of resources perceived by artisanal fishers, a common
complaint is that the “trawlers are polluting” the sea with dying fish and destroying
juvenile stocks. Even when unwanted bycatch is landed, competition with artisanal fish
production can be the cause of further conflict.
Economic incentives for reduction of discards
Several authors125 address the economic aspects of discards. Many such studies model
the theoretical economic impacts or social optima of different discard and bycatch-
related measures based on assumptions regarding fishers’ behaviour. A range126 of
economic incentives for discard reduction can be built into a fisheries management
regime. Taxes127 can be imposed on discards or a charge based on the estimated value
of the entire catch, including discards, may be applied128 through royalty or licence fee
payments. It is then up to vessel operators to make best use of the entire bycatch for
which they are already being charged. Development of theory on discard regulation
may draw on regulatory frameworks and models that consider discards to be a form
of environmental damage (Segerson, 1988). Iceland has operated a “bycatch bank” to
assist in commercializing unwanted fish. Quotas may be debited for failure to land
125 For example, Copes, 1986a; Arnason, 1994; Boyce, 1995.
126 For a comprehensive discussion see Pascoe, 1997. For a discussion of deemed values and other options
see Baulch and Pascoe, 1992; Willmann, 1996.
127 For a theoretical model of such a scheme see Jensen and Vestergaard, 2000.
128 This procedure is followed in Eritrea with respect to foreign vessels. The catch is monitored by 100
percent observer coverage.

Discards in the world’s marine fisheries – an update
74
in proportion to a predetermined length frequency distribution or charges129 may be
levied for failure to land bycatch. Subsidies leading to fleet overcapitalization and
reduced profits may pressure vessel operators to land previously discarded bycatch
(Bostock and Ryder, 1995).
Licence or other fees may be discounted for use of BRDs. As a result of a
Congressional ban on ITQs, they were not considered as an option in the important
United States shrimp fisheries (e.g. Gulf of Mexico) as part of the 1996 regulatory
impact review. Obligatory use of BRDs was recommended as a least cost solution
($117 million/year for a 44 percent reduction in red snapper bycatch) in this fishery.
Placing a monetary value on discards raises fundamental theoretical problems
of valuation of natural resources, e.g. the use of cost–benefit analysis in relation
to environmental issues. Existence values associated with biodiversity or discards
(mortalities) of charismatic species may be highly subjective, possibly because no
objective valuation framework exists.
129 This is an option built into some fisheries access agreements, e.g. in Sierra Leone.

75
5. Conclusions
5.1 SCOPE OF THE STUDY
The study established a method for assessing discards at the global level by creating
a fishery-by-fishery database of landings and discards. The estimate can be checked
or updated through change to individual records of the fisheries. This database is
supplemented by a searchable bibliographic database and electronic archive of many of
the reference materials used in the study. It should be recalled that the sample excludes
a number of important fisheries, notably those in the Russian Far East, the Democratic
Republic of Korea, the Republic of Korea, New Zealand and in United States non-
Federal fisheries. No allowances are made for illegal, unreported and unregulated
(IUU) catches.
The assessment is based on a number of assumptions. A linear relationship between
discards and total landings was assumed. The total quantity of discards was derived
by raising the discard rates obtained from studies by total landings of these fisheries.
Based on expert opinion, fisheries in some countries (notably South and East Asia)
were assigned zero discard rates. Similarly, artisanal and subsistence fisheries in many
countries were assumed to have low or negligible discards, while fisheries harvesting
small pelagics for fishmeal were generally considered to have negligible discards. It
has not been possible to eliminate double counting entirely, particularly with regard
to the tuna fisheries, since the discard assessment for these fisheries used data from the
international tuna management organizations rather than from national sources.
5.2 PRINCIPAL CONCLUSIONS
The current estimate of the global level of discards is concluded to be substantially
lower than the 1994 estimate. The aggregate landings matching the discard data in the
database total 78.4 million tonnes or 94 percent of the average global nominal marine
catch of 83.8 million tonnes.130 The corresponding discards total 6.8 million tonnes,
giving a weighted discard rate of 8.0 percent for the sample. Applying this sample
discard rate to the average global nominal catch gives an estimated annual total of 7.3
million tonnes of discards for the 1992–2001 period.
In geographical terms, the Northeast Atlantic (1.4 million tonnes), the Northwest
Pacific (1.3 million tonnes) and the Western Central Atlantic (0.8 million tonnes)
generate the highest discards. Differences in discard rates between developed and
developing fishing nations are not readily apparent except in the case of Southeast Asia
where discards are generally negligible because of almost full utilization of the catch.
The global values conceal a wide range of discard rates. Trawl fisheries and shrimp
fisheries account for 55 and 27 percent of the recorded discards respectively.
No coherent time series of discard rates is available at the global level. However,
from case studies of a wide range of fisheries, it is apparent that the global level of
discards has decreased in recent years. This is a result of both bycatch reduction and
increased bycatch utilization. Bycatch reduction has occurred not only in Organisation
for Economic Co-operation and Development (OECD) countries (e.g. Northwest
Pacific, Gulf of Mexico, Gulf of Carpentaria, NAFO area) but also in other countries
130 As recorded by FAO Fishstat for the 1992–2001 period and excluding plants and aquatic animals, i.e.
marine mammals and reptiles.

Discards in the world’s marine fisheries – an update
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Conclusions 77
that have introduced bycatch reduction measures (e.g. Argentina and other Latin
American countries).
Increased bycatch utilization has been widespread in Asia, Africa and South and
Central America. Increasing human consumption, improvements in technology (e.g.
surimi products) and the expanding market for aquaculture and animal feeds have also
contributed to this increase.
Incidental catch and discard of charismatic species are creating increased difficulties
for trawl, longline, gillnet and purse-seine fisheries. Additional mitigation and trade
measures may reduce the economic performance of such fisheries. The development
of technologies and enforcement of measures for bycatch reduction and incidental
catch mitigation continue to offset possible further restrictions and declines in these
fisheries.
5.3 ISSUES AND FUTURE DIRECTIONS
5.3.1 Fishery management issues
Quantifying discards
Quantifying discards poses a range of difficulties in sampling, raising and making
effective use of results. Observer programmes appear to be essential for accurate
quantification of discards in most fisheries. The impacts of discards are not easily
quantified and the methods for such impact assessment require further development,
with particular reference to physical accounting and valuation of the broader ecological
impacts.
Public policy
The United Nations General Assembly (UNGA) resolutions, the Code of Conduct
for Responsible Fisheries (CCRF) and the International Plans of Action (IPOAs) are
valuable starting-points for public policy on discards. The range of policy options is
determined by both the biological characteristics of the fishery and the social and
economic environment. Best practice in bycatch reduction is illustrated by a number
of OECD countries, while East and Southeast Asian countries provide valuable
experiences in utilization of bycatch.
A “no-discards” approach to fisheries management holds the high moral ground and
is in conformity with UNGA resolutions and the CCRF. However, the comparative
ecological and social benefits of such an approach need further assessment and its
application in some fisheries may not be practical, at least in the medium term. A range
of complementary measures is required to support an effective “no-discards” regime.
Management framework
Each fishery or management unit is likely to require a specific suite of measures to
optimize bycatch and discard management. Such measures may best be structured
through a bycatch strategy and action plan formulated as an integral part of a fishery
management plan. In overexploited fisheries, effort reduction is likely to be an
essential approach to decreasing discards. Effort reduction may be neglected if efforts
to promote bycatch reduction devices or other technical measures take a central role.
Economic measures can make an important contribution to discard reduction and
bycatch management.
Selective fishing
More selective fishing is advocated as a means of reducing discards. However, selective
fishing is likely to alter ecosystem balance. Any inconsistency that may exist between
promoting more selective fishing and the “ecosystem approach” requires attention
from both theorists and practitioners in order to formulate best scientific advice. Small-
scale fisheries tend to be regarded as being more selective than industrial-scale fishing.

Discards in the world’s marine fisheries – an update
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Conclusions 77
However, by virtue of their ability to exploit most habitats, niches and trophic levels, a
range of small-scale fisheries may have a more damaging effect on the ecosystem.
Discard survival
A high survival rate may reduce the negative impacts of discards. Practices to foster
discard survival can be further evaluated and promoted.
5.3.2 Technical and economic issues
Utilization
Increased utilization of bycatch is an important approach to discard reduction. The
extent to which promotion of ever-greater utilization of marine resources is consistent
with sustainable and responsible fisheries may require attention. The transfer of
improved utilization technologies between fisheries and countries may be of value in
reducing discards and fostering fish food security.
Gear technology
Techniques and technologies for bycatch reduction and incidental catch mitigation
continue to develop. A clearinghouse mechanism to establish the relative merits of
different technologies and develop approaches to their successful introduction may be
of value.
Trade
Incidental catch of charismatic and endangered species poses a threat to certain
fisheries, as mitigation measures may restrict fishing operations and raise costs. In
particular, trade in fish products may be disrupted. Since many charismatic species are
migratory, internationally agreed measures may be required. Internationally accredited
databases of such incidental catches may be necessary in order to evaluate the threats
posed by fisheries and determine appropriate mitigation measures.
5.3.3 Possible FAO actions
Balancing reduction and utilization approaches
Many fisheries, particularly those in developing countries, are likely to seek a balance
between bycatch/discard reduction and bycatch utilization strategies. Guidelines
may be developed that assist the development of a balanced approach consistent with
sustainability of the fishery, the CCRF and the “ecosystem approach”. Case studies
on discards in particular fisheries may be of value in further identifying solutions to
discard problems.
Best practice
Expert advice may be synthesized to provide a catalogue of best practice with regard
to discards and bycatch. The catalogue may include, inter alia: sampling and raising
methodologies and use of observers; approaches to economic analysis of bycatch and
discard issues; the use of discard information in stock assessments, TACs and fisheries
agreements; evaluation of the impacts of discarding; development of appropriate
policies, strategies and plans for bycatch and discard management; and means of
building stakeholder awareness.
Through consultations at a technical level the regional fisheries organizations may
also wish to strengthen their discard-related policies and programmes.
Discards and trade
The discard database may be expanded (or a parallel database established) to
assemble available information on discards and/or incidental catches of charismatic
and endangered species. Such an information base may serve as an accredited source

Discards in the world’s marine fisheries – an update
78
of information on the interaction between fisheries and these species. Institutional
arrangements may be established to assess mitigation measures and facilitate
international consensus on best practice in such measures.
Guidance from COFI
Following appropriate discussion and review of the numerous issues relating to
bycatch and discards, an action plan may be submitted for the consideration of COFI.
Based on a consensus of FAO member countries, a programme may be established to
address the most important discard issues.
The discard database – an evolving tool
In order to maintain131 the discard database as a means by which global discards can
be periodically reassessed, landings and discard values should ideally be verified and
updated by competent authorities at regional and national level. Available catch, bycatch
and discard information may also be collated by fishery in a standardized manner at
national level. Time series of discard information may be compiled for important
fisheries. The merits of compiling global catch statistics on a fishery-by-fishery basis
may be further explored. A link between the discard database and the FAO Global
Fisheries Information System (FIGIS) database has already been established and the
discard database will remain as a “domain” within FIGIS. Cross-linkages between
Fishstat and fishery-by-fishery catch/landings information may also be created.
The discard database is potentially a powerful tool, not only for discard assessment
but also as an initial contribution to a quantitative description of the world’s marine
fisheries on a fishery-by-fishery basis. This database may be extended in several
dimensions, in particular by completing the field on the status of exploitation of each
fishery. Additional fields indicating the value of catches would allow basic economic
analysis by fishery at a global level.
131 Funding for FAO’s discard-related activities is provided under programme entity 233A1: “Reduction of
Discards and Environmental Impact from Fisheries (2002–2005)” and planned under 233A6 “Impact of
Fishing on the Environment (2006–2011)” (FAO, 2001c).

79
Annex A
Results: supplementary tables
A.1 SUMMARY OF DISCARD ESTIMATE WITH CONFIDENCE LIMITS
TABLE 14
Summary of discard estimate with confidence limits
Sum of landings (discard database) (tonnes) 78 432 299
Sum of discards (discard database) (tonnes) 6 824 186
Weighted mean of discard rates (weighted discard rate) 8.00%
Arithmetic mean of discard rates 14.59%
Fishstat ten-year average marine nominal catch 1992–2001 (tonnes) 83 805 355
Discard database landings as percentage of Fishstat ten-year average nominal catch 94%
Variance of discard rates (weighted mean)10.057
Standard deviation (using the weighted mean) 0.238
Standard error of weighted mean 0.011
Confidence (95%) R – – 0.059
Confidence (95%) R + + 0.101
Correlation coefficient 13.31
Range of total estimated discards (discard database):
Lower 6 420 441
Upper 7 512 897
Range for discard rate:
Lower 7.57%
Upper 8.74%
Range of discard rates applied to Fishstat ten-year average global catch:
Lower 6 860 277
Upper 8 027 573
1 Standard deviation and confidence limits have been calculated with reference to the weighted mean. The
variance refers to that of discard rates in the discard database and does not reflect the internal variance of
individual records.
Source: discard database.

Discards in the world’s marine fisheries – an update
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Annex A – Results: supplementary tables 81
A.2 DETAILS OF DISCARDS BY TYPE OF FISHERY
A.2.1 Trawl fisheries
TABLE 15
Shrimp trawl fisheries with highest discards (tonnes)
Country Fishery Period Landings Discard
rate (%) Discards
Tropical shrimp fisheries
United States Gulf of Mexico shrimp 2000 116 408 56.9 480 183
Indonesia Arafura Sea shrimp trawl 1998 53 786 81.7 239 594
Ecuador Ecuador industrial shrimp 1996 24 113 79.1 91 211
Venezuela East and west industrial shrimp trawl 1997 50 423 60.0 75 634
United States South Atlantic Shrimp 2000 14 646 83.3 73 230
Coldwater shrimp fisheries
Peru Industrial shrimp trawl 2000 17 405 81.0 74 200
Argentina Red shrimp tangoneros trawl 2000 36 823 50.1 37 000
Portugal Algarve Nephrops and deepwater shrimp 1996 5 543 70.0 35 000
Japan Small sail trawl 1994 388 95.7 8 691
Norway Shrimp trawl in Nordsjøen/Skagerakk Annual
average
6 000 51.2 6 300
Note: in addition the United Kingdom (Area 27) Nephrops fisheries have discards in the order of 30 000 tonnes.
TABLE 16
Non-shrimp trawl fisheries with highest discards (tonnes) and discard rates
Country Fishery Period Landings Discard
rate (%) Discards
Fisheries with highest discards
All fleets North Sea beam trawl (sole flatfish directed) Average 148 261 69.0 330 000
Japan Small otter and beam trawl powered, other
than shellfish
1994 166 584 60.5 254 874
Argentina Hake otter trawl south of 41oS 1997 468 664 24.0 147 999
United States Washington, Oregon, California multispecies
groundfish
2002 165 730 44.0 130 216
Morocco Industrial otter trawl demersal for
cephalopods, Sparidae, hake
Recent
average
96 771 30.0 95 565
Fisheries with highest discard rates
France Deepwater trawl western waters 1996 13 352 90.0 11 921
Portugal Tagus estuary beam trawl for flatfish and
Crangon
1 750 90.0
Bangladesh Industrial finfish trawl for Saurida, Upeneus,
Sepia
Average 7 140 83.0 34 860
Belgium Flatfish beam trawl 1999 23 000 75.0 69 000
Brunei Darussalam Multispecies finfish and penaeid trawl 1998 1 214 74.2 3 579
United States GOA catcher processor trawl Rex sole directed 2001 7 621 69.1 5 268
TABLE 17
Selected demersal otter trawl fisheries with high discards (tonnes)
Country Fishery Period Landings Discard
rate (%) Discards
Morocco Foreign demersal multispecies1Recent average 146 746 30.0 106 308
Morocco Industrial demersal for cephalopods, sparids
and hake2Recent average 96 771 30.0 95 565
France Offshore multispecies demersal trawl for finfish
and Nephrops Recent average 162 484 28.1 63 502
Japan Offshore trawl for walleye pollock, greenling
and squid 1994 442 412 12.3 61 938
Bangladesh Industrial finfish trawl for Saurida, Upeneus and
Sepia Average 7 140 83.0 34 860
1 Fishery now largely ceased. 2 Moroccan flag.

Discards in the world’s marine fisheries – an update
80
Annex A – Results: supplementary tables 81
TABLE 18
Midwater (pelagic) trawl fisheries with highest discards (tonnes)
Country Fishery Period Landings Discard
rate (%) Discards
Morocco Foreign Atlantic sardine, mackerel, horse
mackerel Recent average 724 680 2.5 35 982
Ireland Mackerel, horse mackerel, blue whiting 2001 155 450 11.0 19 213
Netherlands Horse mackerel 1994 110 000 11.8 14 717
France Sardine and tuna Recent average 22 637 37.7 13 698
France Celtic Sea and Biscay Recent average 35 506 26.3 12 671
TABLE 19
Selected trawl fisheries with high discards (tonnes)
Country Fishery Period Landings Discard
rate (%) Discards
Belgium Flatfish (plaice, sole) beam trawl 1999 23 000 75.0 69 000
Japan East China Sea distant water cephalopod trawl 1994 45 420 38.2 28 070
South Africa Hake trawl 1996 258 509 14.0 31 951
Chile Industrial hake trawl (Regions V to X) 2000 176 033 12.5 25 148
Argentina Coastal iced fish hake trawl (costera) 2000 100 000 13.0 15 000
Peru Industrial merluza trawl 2000 83 361 15.0 14 711
United States BSAI catcher processor yellowfin sole trawl 2001 99 173 29.9 29 667
United States BSAI catcher processor flathead sole trawl 2001 30 196 40.6 12 270

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A.2.2 Other types of fisheries
TABLE 20
Discard rates and discards in other fisheries
Fishery
Discard rate for set of all records with a
discard rate
Discard rate and discards for set of
complete records1
Average
discard rate
(%)
No. records Standard
deviation
Landings
(tonnes)
Discards
(tonnes)
Weighted
discard rate
(%)1
Midwater trawl fisheries
Tuna midwater trawl 4 62 050 26 532 30.0
Small pelagics midwater trawl 5.7 19 0.07 2 763 040 101 285 3.5
Net fisheries (other)
Tuna purse seine 4.85 12 0.02 2 673 378 144 152 5.1
Small pelagics seine 2.0 52 0.03 21 664 338 351 111 1.6
Beach seine 31.9 6 0.27 23 061 1 068 4.4
Gillnet 7.2 48 0.12 3 350 299 29 004 0.5
Line fisheries
Tuna pole and line 0.1 11 0.003 818 505 3 121 0.4
Tuna longline 22.0 37 0.16 1 403 591 560 481 29
Non-tuna line fisheries 8.5 50 0.12 581 560 47 257 7.5
Bottom longline (all) 8.2 20 0.08 209 927 10 988 7.5
Handline 1.8 16 0.02 155 211 3 149 2.0
Squid jig 0.2 9 0.004 1 134 432 1 671 0.1
Finfish jig 1.1 5 0.021 19 296 710 3.5
Dredge, pot and other fisheries
Dredge (scallop, clam, whelk) 24.8 10 0.17 165 660 65 373 28
Hand collection 0.8 16 0.02 256 879 899 0.3
Crustacean pots (lobster, crab) 12.4 12 0.14 185 547 71 077 27.7
Multigear and/or multispecies2 2.4 109 0.07 6 023 146 85 436 1.4
1 Records with landings, discards and discard rate. 2Non-trawl fisheries.
TABLE 21
Discard rates and discards in gillnet fisheries
Country Fishery Period Landings Discard
rate (%) Discards
Fisheries with highest discards
China Chinese small drift gillnet 2000 2 288 713 0.5 11 501
Canada Greenland halibut gillnet 1994 10 455 23.1 3 137
Norway Cod gillnet in north Norway Annual average 31 000 9.1 3 100
Iceland
Bottom gillnet for cod, saithe, haddock
and ling 2001 63 665 3.0 1 969
France
Surface and bottom gillnet for flatfish,
pollock, cod and tuna Average 26 722 6.1 1 736
Fisheries with highest discard rates
United States California drift gillnet for swordfish 66.0 n.a.
United States
Northeast bottom multispecies (sink)
gillnet 31.0 n.a.
EU Mediterranean
countries Cuttlefish trammel 25.5 n.a.
Canada Greenland halibut gillnet (cod, pollock) 1994 10 455 23.1 3 137
Norway Lumpfish gillnet Average 300 23.1 90

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TABLE 22
Percentages of hake discards by year class in the Argentine hake trawl fishery
Year/year class 0 1 2 3
1990 0.82 85 14 0.21
1991 0.94 89 10 0.12
1992 0.83 86 13 0.15
1993 0.90 88 11 0.09
1994 0.92 81 18 0.49
1995 0.90 84 14 0.34
1996 0.93 90 9 0.19
1997 1.27 93 5 0
Source: Dato, Villarino and Cañete, 2000.
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Annex A – Results: supplementary tables 85
A.3 DISCARDS BY LARGE MARINE ECOSYSTEM
TABLE 23
Indicative discards by large marine ecosystem (LME)
Number LME Recorded discards (tonnes)
22 North Sea 909 109
5 Gulf of Mexico 513 597
13 Humboldt Current 439 371
52 Sea of Okhotsk 361 905
27 Canary 269 205
1 East Bering Sea 156 551
3 California Current 150 161
11 Pacific Central-American coastal 139 396
14 Patagonian shelf 138 126
17 North Brazil shelf 136 740
34 Bay of Bengal (including Malaysia) 130 713
32 Arabian Sea 130 272
12 Caribbean Sea 130 184
4/5 Gulf of California/Gulf of Mexico1119 166
24 Celtic-Biscay shelf 100 893
29 Benguela Current 95 896
7/8/9 Northeast USA, Scotian, Newfoundland/Labrador180 151
6 Southeast United States, continental 78 745
30 Agulhas Current 59 899
40 Northeast Australian shelf – Great Barrier Reef 47 655
59 Iceland shelf 45 564
39 North Australian shelf 42 750
2 Gulf of Alaska 41 918
28 Guinea Current 40 513
24 Celtic-Biscay 37 168
25 Iberian coastal 35 605
42 Southeast Australian shelf 32 976
36/37/38 South China, Sulu-Celebes, Indonesian Seas130 818
36 South China Sea 21 405
15 South Brazil shelf 20 372
26 Mediterranean 17 239
23 Baltic Sea 14 203
20 Barents Sea 13 455
7 Northeast United States, continental 11 533
31 Somali Current 8 874
36/37 South China, Sulu-Celebes Seas17 521
16 East Brazil shelf 7 062
21 Norwegian shelf 5 840
33 Red Sea 4 832
61 Antarctic 2 079
19 East Greenland shelf 1 770
9 Newfoundland/Labrador shelf 1 242
62 Black Sea 715
Other LMEs 676
Outside LMEs or not attributable to an LME12 227 489
Total 6 824 186
1 As some fisheries harvest from more than one LME, discards in certain areas are difficult to attribute by LME, e.g.
distribution of Malaysian discards between the Gulf of Thailand and South China Sea.
Source: discard database.

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FIGURE 2
Recorded discards by large marine ecosystem

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Annex A – Results: supplementary tables 87
A.4 DISCARDS BY COUNTRY AND IN LOW INCOME FOOD DEFICIT COUNTRIES
(LIFDCS)
Table 24 is provided for record purposes only. Because of the bias in the discard
database towards fisheries that discard, discard rates and total discards on a country-
by-country basis are not necessarily representative of total discards or discard rate
of the aggregate fisheries of the country. Only complete records are used in the table
so that some fisheries with high discard rates, but for which landings information is
unavailable are not included. The table excludes tuna and HMS fisheries.
Table 24 also highlights discard information from low income food deficient
countries (LIFDCs). The table does not provide a total of discards from these countries
but is intended to draw attention to countries and fisheries where further actions may
be directed to improve bycatch utilization. As the table is based only on records where
the volume of discards is available certain fisheries are not included.
TABLE 24
Landings, discards (tonnes) and weighted discard rate by country or area (EEZ,
not flag state)
Country1Landings Discards Discard rate (%)
American Samoa 460 0 0.0
Angola 232 325 46 594 16.7
Anguilla 225 0 0.0
Antigua and Barbuda 1 369 0 0.0
Argentina 622 964 109 000 14.9
Aruba 168 0 0.0
Australia 97 644 120 981 55.3
Bahamas 10 253 0 0.0
Bahrain 8 164 2 571 24.0
Bangladesh 314 966 64 578 17.0
Barbados 3 316 0 0.0
Belize 111 284 71.9
Benin 8 146 41 0.5
Bermuda 430 0 0.0
Brazil 480 574 54 892 10.3
British Virgin Islands 236 0 0.0
Brunei Darussalam 1 214 3 579 74.7
Bulgaria 3 353 436 11.5
Cambodia 49 343 0 0.0
Cameroon 61 407 367 0.6
Canada 789 061 90 021 10.2
Cape Verde 10 881 54 0.5
Cayman Islands 123 0 0.0
Chile 4 360 251 89 155 2.0
China 14 777 934 74 261 0.5
Colombia 9 095 14 377 61.3
Comoros 6 951 35 0.5
Cook Islands 836 0 0.0
Costa Rica 2 683 2 437 47.6
Côte d’Ivoire 30 000 151 0.5
Cuba 19 227 0 0.0
Djibouti 350 0 0.0
Dominica 1 104 0 0.0
Dominican Republic 942 3 964 80.8
Ecuador 24 113 91 211 79.1
El Salvador 37 678 10 397 21.6
Equatorial Guinea 5 400 27 0.5
Eritrea 16 989 3 792 18.2
EU 12 211 8 135 40.0
Falklands/Malvinas 228 417 11 127 4.6

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Fiji Islands 20 832 0 0.0
Finland 104 000 200 0.2
France 729 517 194 268 21.0
France (Réunion) 2 722 27 1.0
French Guyana 9 324 49 822 84.2
French Polynesia 6 631 0 0.0
Gabon 25 000 253 1.0
Gambia 39 098 5 124 11.6
Ghana 105 936 1 445 1.3
Greece 35 000 17 070 32.8
Grenada 1 661 0 0.0
Guadeloupe 9 641 0 0.0
Guam 472 0 0.0
Guatemala 16 100 50 950 76.0
Guinea 103 913 16 684 13.8
Guinea-Bissau 50 021 18 500 27.0
Guyana 26 870 29 960 52.7
Haiti 398 1 402 77.9
Honduras 11 815 27 335 69.8
Iceland 1 969 672 45 564 2.3
India 2 849 066 57 917 2.0
Indonesia 3 104 788 270 412 8.0
Iran, Islamic Rep. of 43 272 29 208 40.3
Ireland 214 903 29 569 12.1
Japan 6 491 001 918 436 12.4
Jordan 116 0 0.0
Kenya 8 272 2 940 26.2
Kiribati 16 000 0 0.0
Korea, Dem. Rep. of 221 253 1 112 0.5
Korea, Rep. of 197 913 995 0.5
Kuwait 5 602 41 980 88.2
Liberia 4 494 23 0.5
Madagascar 69 184 31 618 31.4
Malaysia 1 027 276 10 377 1.0
Maldives 12 599 59 0.5
Marshall Islands 3 273 0 0.0
Martinique 5 352 0 0.0
Mauritania 15 000 75 0.5
Mauritius 10 694 54 0.5
Mexico 541 423 137 873 20.3
Micronesia, Fed. States 5 000 0 0.0
Montserrat 46 0 0.0
Morocco 924 450 222 457 19.4
Mozambique 68 787 26 525 27.8
Myanmar 880 594 27 371 3.0
Namibia 522 557 13 454 2.5
Nauru 425 0 0.0
Netherlands 110 000 14 717 11.8
New Caledonia 3 418 0 0.0
Nicaragua 5 776 6 346 52.4
Nigeria 190 722 2 792 1.4
Niue 206 0 0.0
Norfolk Island 0 0 0.0
Northern Mariana Is. 2 966 0 0.0
Norway 2 516 350 102 611 3.9
Oman 135 957 1 384 1.0
Pakistan 228 676 35 467 13.4
Palau 2 103 0 0.0
Panama 101 964 33 483 24.7
Papua New Guinea 33 167 6 150 15.6
Peru 10 291 633 350 215 3.3

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Philippines 744 583 7 521 1.0
Pitcairn Islands 8 0 0.0
Portugal 6 303 35 605 85.0
Russian Federation 400 000 361 905 47.5
Saint Helena 781 0 0.0
Saint Kitts and Nevis 295 0 0.0
Saint Lucia 1 621 0 0.0
Samoa 7 190 0 0.0
Saudi Arabia 24 833 1 014 3.9
Senegal 376 153 25 209 6.3
Seychelles 4 433 22 0.5
Sierra Leone 45 910 231 0.5
Solomon Islands 16 634 0 0.0
Somalia 4 000 0 0.0
South Africa 872 935 37 570 4.1
Spain 6 343 212 3.2
Sri Lanka 274 760 1 367 0.5
Sudan 5 094 26 0.5
Suriname 5 500 29 500 84.3
Syrian Arab Republic 2 408 12 0.5
Tanzania, United Rep. 51 147 5 934 10.4
Thailand 2 752 878 27 807 1.0
Timor-Leste 381 2 0.5
Tokelau 200 0 0.0
Tonga 7 036 0 0.0
Trinidad and Tobago 6 639 8 859 57.2
Tunisia 29 295 147 0.5
Turkey 282 150 279 0.1
Turks and Caicos Is. 1 310 0 0.0
Tuvalu 1 100 0 0.0
United Kingdom 27 343 16 654 37.9
United States 3 344 438 927 599 21.7
Uruguay 112 572 18 649 14.2
Vanuatu 2 930 0 0.0
Venezuela 213 025 96 820 31.2
Viet Nam 3 547 346 17 826 0.5
Wallis and Futuna Is. 917 0 0.0
Yemen 50 523 531 1.0
Total 69 580 728 5 207 041 7.0
1 LIFDCs are shaded in the table.

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A.5 DISCARDED SPECIES AND INCIDENTAL CATCHES
TABLE 25
Commonly discarded species in different fisheries (indicative)
Fishery Commonly discarded species
Penaeid shrimp trawl Small finfish caught as bycatch. Species groups include Leiognathidae
(ponyfish), Nemipteridae (threadfin), Trichurius sp. (hairtails), Decapterus
sp., Saurida sp. (Synodontidae), small shrimp, sharks and rays, as well as
jellyfish and juveniles of many commercial whitefish species such as croakers,
snappers, and emperors
Nephrops trawl Juvenile whiting, haddock, cod; broken, undersized Nephrops and flatfish
Finfish (roundfish) trawl
fisheries
Juvenile commercial species, in particular demersal species such as whiting,
haddock, hake, Sciaenidae and lower value commercial species such as horse
mackerel, Rastrelliger and elasmobranchs
Hake trawl Small hake and horse mackerel (all fisheries), kingklip and rattails (Africa),
arrowtooth flounder, dogfish and ratfish (North Pacific)
Flatfish trawl Juveniles and target species under MLS; molluscs, echinoderms (sand urchins
and starfish), crabs, rajids. Cod, haddock, whiting, plaice, saithe, dab, dogfish,
shrimp and Nephrops (EU). Arrowtooth flounder is a major component of
discards in the GOA/BSAI fisheries for yellowfin sole, flathead sole and other
flatfish
Deepwater trawl Teleosts including grenadiers, whiptails, rabbitfish and oreos; chondrichthyans
such as birdbeak dogfish (Deania), batoids and chimaeroids
Small pelagics midwater
trawl
Small sizes of target species and non-target species such as horse mackerel in
mackerel fisheries, horse mackerel (EU countries), sardine, pilchard, mackerel
and sprat. Small-sized fish of the target species may be discarded as a result of
highgrading in the quota-managed European fisheries or because processing
equipment cannot handle smaller sizes. Dolphins (1.4 dolphins/100 tow-hours
in French and Irish tuna fisheries) and sunfish are caught incidentally
Purse seine for small
pelagics
Primarily non-target small pelagics including horse mackerel, Scomber
japonicus, Boops, Belone sp., jellyfish, juveniles of other species and small
quantities of sharks
Tuna purse seine Non-commercial tunas (e.g. bonito, dogtooth tuna), rainbow runner,
dolphinfish, jacks, shark, billfish, mantas and undersized skipjack and
yellowfin, dolphins. Large quantities of jellyfish are discarded in the bluefish
and bonito fisheries in Turkish waters. Incidental catches of dolphins
Tuna/HMS longline
fisheries
The principal discards include Prionace glauca (blue shark), which is probably
the most commonly discarded species, Carcharinus sp. and other sharks, shark/
marine mammal-damaged fish, albatross, petrels and other seabirds. Frigate
tuna, Kawakawa, Indo-Pacific king mackerel, and narrow-barred Spanish
mackerel
Bottom longline Non-quota species. Arrowtooth flounder GOA/BSAI fisheries), starry ray, dab
and redfish (Iceland, Faeroe Islands), hake, shark and kingclip (South Africa),
and macrourids and rajids in the CCAMLR area
Gillnet fisheries Dogfish, skate, sculpin (Canada), cod, haddock, plaice, saithe and dab
(Europe)
United States Northwest
Pacific groundfish
fisheries
Molluscs and crustaceans. Trawlers are obliged to discard large volumes of
crabs. Many species of discarded shellfish survive.1 These include lobster,
crab, scallop and oyster. Discard estimates can prove difficult if landings are
expressed in numbers, weight of meat or volume (e.g. in bushels)
Otter trawl ICES VIIe,f,h Benthos discarded included echinoderms, Marthasterias glacialis, Asterias
rubens, Ophiura ophiura and whelk (Buccinum undatum) (Lart et al., 2002b)
1 Shrimp, giant spider crabs and ascidians have a high mortality. In the Bass Straits scallop dredge fishery under 3
percent of dredged items are bycatch, most of which are undamaged when discarded.

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TABLE 26
Incidental catch of seabirds, turtles and marine mammals in selected fisheries
Fishery Species Incidental catch rate Measures/notes Source
Danish bottom set gillnet Harbour
porpoise
Mean 5, 129 (1987–2001) Use of pingers in cod/wreck fishery judged 100%
effective
STECF/SGFEN (2002), quoting
Vinther and Larsen, 2002
Netherlands horse mackerel trawl Dolphin Nine dolphins in six tows BIOECO/93/017
Morizur et al., 1996
France hake pelagic trawl Dolphin 1.2 dolphins /100 tow–hours BIOECO/93/017 (data 1994)
Morizur et al., 1996
France pelagic trawl for seabass Dolphin 1.5 dolphins /100 tow–hours BIOECO/93/017 (data 1994)
Morizur et al., 1996
Ireland albacore midwater trawl Dolphin 1.4 dolphin/100 tow–hours (French), sunfish No bluefin quota except as bycatch BIOECO/93/017 (data 1994)
Morizur et al., 1996
United Kingdom bass pelagic trawl
– English Channel
Dolphin 61 common dolphin in 122 monitored tows, 2001
and 2002
Tows in mackerel, pilchard and blue whiting fisheries
monitored but 0 mortality
STECF/SGFEN, 2002
Netherlands pelagic freezer trawl Dolphin, pilot
whale
Eight white–sided dolphin, common dolphin, pilot
whale, 0.06 mm per haul
Observer reports, study of seasons and distribution of
interaction
Couperus, 1997 (data 1995–
1996)
Spain longline Mammals,
seabirds,
turtles
Mammals, seabirds, turtles Caswell et al., 1998
France thonaille Dolphin 0.6–1.2 per 100 tuna caught Stenella coeruleoalba
(striped dolphin)
Mandatory pingers, ACCOBAMS STECF/SGFEN, 2002
Australia states Queensland inshore
commercial
Dugong n.a. Harris, A. 1997
United States Western Pacific
pelagic longline
Seabirds,
albatross
3 073 albatross (two spp.). 0.013 (tuna sets) to 0.76
(swordfish sets) birds per set
See FMP and EIA NMFS/NOAA, 2001 (data
1994–1999)
United States Pacific halibut birds Birds 6.1 per mill. Hooks Tori lines, research on video monitoring, fisher
interviews
IPHC Web site (Alaska) fisher
interviews
Peru small–scale longline
– northern Peru
Waved
albatross
(Diomedea
irrorata)
0.74 to 1.75 birds/1 000 hooks Change from gillnetting to avoid cetacean bycatch,
fisher interviews
Guillen, Jahncke and Goya,
2000, p. 132 (data 1999)
United States Atlantic HMS Birds, turtles 1 307 turtles, 48 birds, 200 marine mammals US bycatch matrix
Spain Mediterranean swordfish
longline
Turtles 0.18–2.73 per 1 000 hooks Cramer, Bertolino and Scott,
1995 (data 1986–1995)

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Fishery Species Incidental catch rate Measures/notes Source
Spain Mediterranean surface and
bottom longline
Cory’s
shearwater
(Calonectris
diomedea)
0.16 to 0.69 birds per 1 000 hooks 437–1 836 shearwaters killed annually in the area Belda and Sanchez, 2001
All SPC tuna purse seine Marine
mammals
3.8 per 1 000 sets SPC observer data P. Sharples SPC, pers. comm.
(observer data 1997–2003)
All SPC tuna purse seine Turtles 0.9 per 1 000 sets SPC observer data P. Sharples SPC, pers. comm.
(observer data 1997–2003)
All SPC tuna longline Birds 0.12 per 1 000 hooks SPC observer data P. Sharples SPC, pers. comm.
(observer data 1997–2003)
All SPC tuna longline Reptiles 0.02 per 1 000 hooks SPC observer data P. Sharples SPC, pers. comm.
(observer data 1997–2003)
All SPC tuna longline Marine
mammals
0.02 per 1 000 hooks High % alive when hauling, survival rate unknown P. Sharples SPC, pers. comm.
(observer data 1997–2003)
IATTC purse seine Dolphins 2 129 dolphins killed Quota, international agreement, observers,
experimental fishing
IATTC, 2001 (data 1999)
United States /IATTC tuna
dolphin set purse seine
Dolphins
encircled
2.34 million per year – number encircled, most are
released, >300 per set
See IATTC rules Southwest Fisheries Science
Center, 2002 (data average
of programme years)
Notes
With regard to the absolute levels of cetacean and endangered species discards, it should be noted that the entanglement and mortality of, for example, a single North Atlantic right whale (population 300) is
of greater concern than the capture of several common dolphins (population 200 000 in the area).
Records of discards of lesser–known aquatic animals such as saltwater crocodiles and sea snakes are uncommon.
Source: discard database.

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A.6 EXAMPLES OF TRENDS IN DISCARD REDUCTION AND INCREASE
As this report gives a substantially lower estimate of global discards, further evidence of this reduction is provided in Table 27.
TABLE 27
Examples of discard reduction in selected fisheries
Area Fishery Discard reduction Period Principal reasons Source
21 Canada northern
shrimp
Bycatch reduced from 15.2 to 5.6% of catch.
“… groundfish mortality in Canadian shrimp
fisheries has been reduced markedly, and
virtually eliminated in the sensitive groundfish
areas”
1991–1994 BRD (Nordmore); reduction in groundfish stocks,
responsible fishing practices, requirement to
change area
Duthie, 1997a
21 US Atlantic
pelagic longline
16.5% for pelagic shark
22.1% for large coastal shark
2001 compared to
1999–2000 average
Time, area closures NMFS/NOAA, 2003
27 France Nephrops
and whitefish
trawl
86–100% of fishers believe that discarding has
declined
2000 Agricultural Economics Research
Institute, 2000
27 Norway shrimp
trawl
… greatly reduced, resulting in improved catch
handling times and quality of the shrimp catch
n.a. Sort–XTM BRD MacMullen, 1998
31 Central American
shrimp fisheries
“… [bycatch]…caught was still high (between
90 and 97% of the total catch) but …
utilization of the bycatch has increased”
Growing consumption of bycatch FAO workshop, Cuba, 1997
31 Gulf of Mexico
shrimp trawl
(United States)
40% reduction in finfish bycatch mortality;
10% increase in shrimp catch (2001); red
snapper (main discard) landings doubled
In comparison
with1998 levels
FMP and BRDs Federal Register, 2003, p. 11512
41 Argentina Juvenile hake Late 1990s Use of BRDs IMARPE
47 South Africa,
West Coast rock
lobster
Major reduction in discards in late 1990s Increase in MLS Poseidon Aquatic Resource
Management Ltd, 2003, p.75
51 Madagascar
shrimp trawl
Bycatch reduced by 49% 2000 Use of BRDs Mounsey, 2000
57 India – Visak
shrimp freezer
trawl
Early 1990s Freezer fleet has disappeared BOBP–IGO, pers. comm.
57 Myanmar
trawlers
60% down to 7–8% for trawl fleet Mid–1990s to 2003 Building of fishmeal plants, use for animal/fish
feed/human consumption
Myanmar Fisheries Federation,
2003, pers. comm.
67 BSAI/GOA See Tables 28 and 29
71 Western Central
Pacific
“… available quantitative information
indicates that there has been a considerable
increase in the utilization of the fishery catch
over the last decade”
1986–1996 Harris, 1997

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Area Fishery Discard reduction Period Principal reasons Source
87 Peru hake
demersal trawl
A “significant reduction” from 30% in 1996 1996 – late 1990s Use of juveniles and other bycatch for surimi and
fish blocks
R.G. Carrasco, IMARPE, pers.
comm.
United States (in
general)
“In general, discard levels in the United States
have declined over the past several years”
1994–1998 “… [attributed to] … new technologies and
management measures … decline in stocks …
increased retention of fish previously discarded”
Alverson, 1998
Various countries Unknown Legislation designed to reduce bycatch and/or
discards in place in over 30 countries
Bycatch reduction programmes in over 20 countries
Poseidon Aquatic Resource
Management Ltd, 2003
Global/high seas
shark
Unknown 2000–2003 Implementation of the IPOA on sharks. United
States, EU, Costa Rica and others require landing of
carcasses
United States legislation, Council
Regulation (EC), 2003

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A.6.1 Declining discards in Alaskan and United States West Coast fisheries
The walleye (Alaska) pollock fishery in the North Pacific is the world’s largest demersal
whitefish fishery. Over 90 percent of landings are harvested by midwater trawl and the
fishery represents approximately 25 percent of United States landings by volume. The
following tables show the decline in certain categories of discards in recent years in the
BSAI fishery.
TABLE 28
Estimated pollock and non-target groundfish total and discarded catch in directed BSAI pollock
fisheries from 1997 to 2000 (tonnes)
Year Total catch Total discarded Discards (% total catch)
1997 1 097 657 41 505 3.78
1998 1 022 374 10 472 1.02
1999 957 713 9 704 1.01
2000 1 109 250 12 81 1.1
Source: Bernstein et al., 2002 (Table 7).
TABLE 29
Average rate of incidental catch of halibut, crab and salmon in the directed BSAI pollock fishery
from 1997 to 2000
Year Per tonne of groundfish
Halibut (kg) Numbers of crab Numbers of salmon
1997 0.243 0.026 0.062
1998 0.345 0.070 0.066
1999 0.180 0.003 0.077
2000 0.112 0.001 0.062
Note: all incidental catch of these species must be discarded.
Source: Bernstein et al., 2002 (Table 9).
Reasons for the reduction in BSAI/GOA discards
The reasons for these declines are closely linked to the management regimes for the
BSAI/GOA fisheries and require some understanding of the complex nature and
history of these fisheries (see references for details). Some of the principal reasons for
effective bycatch management are that:
• BSAI/GOA fish stocks are not overfished;1
• there are strong incentives for bycatch reduction;
• enforcement is effective;
• bycatch is cooperatively managed; and
• fishery bycatch information is used as a real-time management tool.
Incentives
When bycatch limits on crab, salmon and halibut are reached, the legislation requires
that the fishery be closed, creating a strong incentive to avoid bycatch. The bycatch of
individual vessels is published, creating peer pressure on vessel operators.
Effective enforcement
A 100 percent observer coverage (larger vessels) ensures that all bycatch and discards
are recorded. Demersal finfish discards are recorded by weight. Salmon and crab
discards are recorded by number. Regulations require that all salmon, crab and halibut
be discarded. Vessel operators actively cooperate with observers to ensure that discard
records are accurate.
1 Out of 244 fish stocks only two are considered to be overfished (NMFS, 2001).

Discards in the world’s marine fisheries – an update
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Annex A – Results: supplementary tables 95
Cooperative management of the bycatch allocation
The Pollock Conservation Cooperative (PCC) and High Sea Catcher’s Cooperative
(Joint Report of the Pollock Conservation Cooperative and High Sea Catcher’s
Cooperative, 2002), operational since 1999, effectively acts as a voluntary/cooperative
ITQ system, giving many of the benefits of an ITQ system to the eight PCC members,
which control approximately 37 percent of the catch allocation of the directed pollock
fishery.
The members contract a private firm to which observer data, including bycatch data,
are uploaded once or twice a day. Two observers on board each vessel sample 98.9
percent of hauls. Groundfish discards are less than 0.5 percent. Information on bycatch
levels is shared between operators in near real time, identifying bycatch “hotspots”
and allowing vessels to move rapidly to grounds with low bycatch. The cooperative
arrangement has forfeiture (penalty) clauses for breach of bycatch limits and there has
been full compliance with these limits. The benefits of the cooperative management
regime have included:
• improved processing yield (larger fish) and more time to search for larger fish (no
“race for fish”);
• processing at optimum speed for product quality and yield (recovery rate);
• reduced capitalization in vessels and processing equipment (although there was
increased investment to vary product mix and meet market requirements);
• substantial contributions to fisheries research;
• reduced bycatch of unwanted species through movement to low bycatch areas;
and
• reduction of the Olympic-style fishery (race for fish), reduction of over 30 percent
in effort and increased economic rent generation
Similar cooperative arrangements with regard to bycatch exist in the Pacific whiting
fishery (see Box 7), Weathervane scallop fishery in the United States (Brawn and
Scheirer, 2002) and the Hoki fishery in New Zealand (Hoki Fishery Management
Company, 2003).
BOX 7
Pacific Whiting Fish Harvesting Cooperative
Pacific Whiting Conservation Cooperative (PWCC) members have achieved significant
reductions in bycatch. Pacific whiting, like Bering Sea pollock, is harvested using
midwater trawl nets. Bycatch rates for both fisheries are from 1 to 2 percent. The
whiting catcher/processor fleet operating within the construct of a cooperative achieves
even greater bycatch reductions. The bycatch rate for yellowtail rockfish decreased by
more than 60 percent from 2.47 kg of yellowtail rock per tonne of whiting under the
race for fish to 0.96 kg per tonne under the cooperative arrangement. During the same
period, yellowtail rockfish bycatch by smaller trawl vessels delivering to mother ships
increased from 3.43 to 6.51 kg per tonne.
A major contributor to the reduction in bycatch is the fisher’s ability to discontinue
fishing in high bycatch areas without sacrificing harvesting opportunities. To help avoid
bycatch “hotspots”, PWCC members report catch and bycatch data electronically to
Sea State, a private sector firm specializing in fisheries data collection and analysis. Sea
State collates the data and reports back to PWCC vessels on a “real-time” basis, advising
vessel captains to avoid areas in which high bycatch is likely to occur. Because they do
not have to race for fish, boats can take the time to move to areas with low bycatch.

Discards in the world’s marine fisheries – an update
96
A.6.2 Examples of increases in discards
There are few examples of fisheries with increasing discards. Some deepwater fisheries
are producing discards that did not hitherto exist, although active market promotion is
under way for such unfamiliar species. Quota restrictions in EU fisheries are resulting
in high discard rates, although overfishing reduces the absolute quantity of discards.
There is evidence of substantial discarding in a number of major fisheries in the Russian
Far East.

97
Annex B
Evolution of global discard
estimates
As already noted, the current updated estimate of global discards is substantially lower
than that given in FAO Fisheries Technical Paper No. 339 (the Alverson assessment).
Annex B aims to:
• briefly outline the method used in the Alverson assessment;
• examine some of the reasons for the differences; and
• provide an overview of the evolution of the discard estimates.
Following the publication of the Alverson assessment, FAO held a Technical
Consultation at which regional experts provided revised estimates of discards for
selected FAO statistical areas and suggested reasons why the assessment may have
overestimated discards in certain fisheries and areas.
B.1 METHOD USED IN THE ALVERSON ASSESSMENT
The Alverson assessment estimated discards by region and in relation to target species,
using FAO Fishstat for the global catch data. The 1 700 discard records included
information both on numbers of fish discarded and on weights of fish discarded. The
fisheries of the North Atlantic and Northwest Pacific provided over 70 percent of the
records. Average discard rates associated with target species and each FAO statistical
area were applied to nominal catch by species or species group, as provided in FAO
Fishstat. As there is no a priori relationship between landings of target species and
discards, and as the nominal catch of a species may often represent the retained catch of
several different fisheries, each with a different fishing gear, target species and different
level of discards, the extrapolation to area and global level may have resulted in some
double counting (Murawski, 1996).
In 1998, the lead author of the 1994 assessment recognized its various shortcomings
together with the substantial changes that were occurring in many fisheries, and
an update on discarding practices and unobserved fishing mortality was published
(Alverson, 1998). However, the global estimate was not recalculated.
B.2 TECHNICAL CONSULTATION ON REDUCTION OF WASTAGE IN FISHERIES
In 1996, the FAO Technical Consultation on Reduction of Wastage in Fisheries
identified a number of difficulties arising with the methods used in the Alverson
assessment, which were considered to contribute to an overestimate of global discards.
As part of the contributions to the Technical Consultation, several authors prepared
revised estimates of discards for selected FAO statistical areas, e.g. 4 million rather than
9.13 million tonnes for the Northwest Pacific.
The comments on the Alverson assessment in Box 8 are taken from the various
papers in FAO Fisheries Report No. 547 (Clucas and James, 1997). It is stressed that
the authors of the comments indicated that these were not intended to undermine the
major contribution made by FAO Fisheries Technical Paper No. 339, but to contribute
to a more accurate estimate of global discards.

Discards in the world’s marine fisheries – an update
98
Annex B – Evolution of global discard estimates 99
B.2.1 Alternative approach to global discard estimation
The Technical Consultation suggested an enhanced approach1 to include reference
to the type of fishing method and provided a practical demonstration of the
methodology. The current study has attempted to apply the methodology proposed
by the Technical Consultation in the wider global context. The matrix of three
spreadsheets (Table 30) was found unmanageable at the global level, partly because
of the lack of information on many fisheries. Species–by–species information was
also considered too detailed and unnecessary in the context of a global study,
although clearly of considerable value at the country or fishery level.
1 Developed by Smith (1997) and Duthie (1997a,b). See Appendix C to the Technical Consultation (FAO
Fisheries Report No. 547).
BOX 8
Specific comments on the Alverson assessment1
Area 21
Duthie, 1997a,b
• Significant digits and error variance lacking (remains a problem in
current study)
• Further consideration of factory vessels (remains a problem in
current study)
Area 21
Kennelly, 1997
• Lack of detailed explanation as to how the estimates were made
• Lack of clarity regarding assumptions
• Impossible to judge validity of assumptions
• Use of target species, particularly in multispecies fisheries
Area 27
Smith, 1997
• 20–30 references for entire Northeast Atlantic and possible
application of North Sea discard rates to all of Area 27
• Species–by–species approach requiring greater number of records
for multispecies fisheries
• Species with low discard rates accorded high discard rates by default
as no discard information exists
• Interpretation problems regarding Norway pout (110 000 tonnes
discarded), sand eels (806 000 tonnes discarded), capelin (492 000
tonnes discarded) and blue whiting
Area 34
Balguerías, 1997
• Limited source material and some reference material on discards
overlooked
Area 47
Japp, 1997
• Lacking specific information on Area 47
Area 61
Matsuoka, 1997
• Overestimate of discards because of double counting and an estimate
of approximately 5 million tonnes lower provided
Area 71
Harris, 1997
• No allowance made for retained bycatch in shrimp fisheries. Major
difference between estimate for shrimp fisheries and that made by
Andrew and Pepperell (1992) – 1.38 million tonnes compared with
0.29–0.59 million tonnes. Discard ratios from temperate waters
apparently applied in tropical waters. No allowance made for
artisanal fisheries
1 From papers presented at the Technical Consultation on Reduction of Wastage in Fisheries,
Tokyo, November 1996. FAO Fisheries Report No. 547 (Suppl.). (FAO, 1996b).

Discards in the world’s marine fisheries – an update
98
Annex B – Evolution of global discard estimates 99
TABLE 30
Matrix for calculation of discards as proposed by the Technical Consultation
B.3 GLOBAL DISCARD ESTIMATES PRESENTED IN SOFIA
The conclusions reached in the Alverson assessment were presented in The State
of Fisheries and Aquaculture 1996 (SOFIA) (FAO, 1996a). A revised estimate of 20
million tonnes was presented in SOFIA 1998 (FAO, 1998). This estimate has been
largely ignored and is rarely cited in the literature, possibly because the revised estimate
was not substantiated by FAO in any published documents.
Based on information provided at the Technical Consultation, the probable basis
for the global discard estimate in SOFIA 1998 has been reconstructed (Table 32) and
derives a similar quantum of discards. Although not directly comparable, but in order
to demonstrate the evolution of the discard estimates, the results of the Alverson
assessment, the Technical Consultation, the SOFIA estimate and this reassessment are
presented in Table 31.
B.4 REVISION OF ALVERSON ESTIMATE USING TOKYO WORKSHOP
INFORMATION
The sources of major changes in discard estimates (see also Box 8) indicated in the
Tokyo workshop were as follows:
• Area 27 – substantial change in source of discards although little change in total
quantity (Smith);
• industrial and artisanal fisheries in South and Southeast Asia (Chee, Harris);
• China, which is reported to have no discards (Zhou and Ye); and
• revision of Area 61 discard estimate (Matsuoka).
1. Catch/landings Gear 1 Gear 2 Gear 3
Species 1
Species 2
Species 3 2. Discard ratios Gear 1 Gear 2 Gear 3
Species 1
Species 2
Species 3 3. Discards (tonnes) Gear 1 Gear 2 Gear 3
Species 1
Species 2
Species 3
1 x 2 = 3
BOX 9
Discard estimates in SOFIA 1996 and SOFIA 1998
SOFIA 1996
“In 1994, FAO showed that the proportion of the world fish catch made up of bycatch
might be much larger than previously considered and estimated that discarding
amounted to an average of 27 million tonnes per year (or about 32 percent of the total
reported annual production of marine capture fisheries).”
SOFIA 1998
“A subsequent re–evaluation of these estimates, together with adjustments allowing for
subsequent reductions in discarding, indicates that current levels are at the lower end of
the range. The most recent FAO estimate of 20 million tonnes, if correct, is equivalent to
25 percent of the reported annual production from marine capture fisheries, which are
those from which most of the discards derive.”

Discards in the world’s marine fisheries – an update
100
Annex B – Evolution of global discard estimates 101
However, assuming that the 20 million tonne estimate in SOFIA 1998 was based
on the type of calculation provided in Table 32, it is clear that it was not really a re-
estimate, but a modified version of the estimate provided in the Alverson assessment.
As the papers presented in the Tokyo workshop did not cover many of the FAO areas
(e.g. South America, Indian Ocean), the SOFIA 1998 figure was at best a partial re-
estimate. The adjustments made as a result of the Tokyo workshop reduced the discard
estimate by approximately 45 percent for the six FAO areas considered.
Again, it is stressed that the different methods and approaches used in the two
studies do not make the estimates directly comparable and considerable caution is
required in drawing conclusions.
TABLE 31
Evolution of discard estimates (tonnes), 1994–2004
FAO area FAO Fisheries
Technical Paper
No. 339 (Alverson
Table 5)
FAO Fisheries
Report No.
547/SOFIA 1998
(approx.)1
Current
study
Arctic Sea 18 0
Northwest Atlantic 21 685 949 699 689 92 926
Northeast Atlantic 27 3 671 346 2 891 080 1 408 931
West Central Atlantic 31 1 600 897 1 600 897 831 808
East Central Atlantic 34 594 232 185 956 309 718
Mediterranean/Black Sea 37 564 613 564 613 17 954
Southwest Atlantic 41 802 884 802 884 197 618
Southeast Atlantic 47 277 730 116 652 120 283
West Indian Ocean 51 1 471 274 1 471 274 205 428
East Indian Ocean 57 802 189 802 189 151 190
Northwest Pacific 61 9 131 752 4 000 000 1 355 822
Northeast Pacific 67 924 783 734 069 192 829
West Central Pacific 71 2 776 726 1 200 000 407 826
East Central Pacific 77 767 444 767 444 167 351
Southwest Pacific 81 293 394 293 394 35 475
Southeast Pacific 87 2 601 640 2 601 640 530 582
Multiple area 31, 77 27 335
Multiple area 67, 77 150 161
Multiple area 71, 77 2 138
Global shark fin 206 815
Tunas, bonitos, billfish
Atlantic and Mediterranean (ICCAT area) (21, 27, 31, 34, 41, 48) 159 466
Indian Ocean (IOTC area) (51, 57) 139 465
Pacific E. Central (IATTC area) (67, 77, 87) 56 508
Pacific SW and W. Central (SPC area) (71, 81) 162 068
Subtotal tuna 517 507
Antarctic
Atlantic, Antarctic 35 119 35 119
Indian Ocean, Antarctic 10 018 10 018
Pacific, Antarctic 109 109
Subtotal Antarctic CCAMLR (48, 58, 88) 2 079
Global estimate of discards 27 012 099 19 185 303 6 931 776
1 See Table 32 for derivation of estimate.

Discards in the world’s marine fisheries – an update
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Annex B – Evolution of global discard estimates 101
TABLE 32
Possible derivation of the estimate of discards (tonnes) referred to in SOFIA 1998
FAO area FAO Fisheries
Technical
Paper
No. 339
(Alverson
Table 5)
FAO
Fisheries
Report No.
547 (Suppl.)
Tokyo
discard
estimate
FAO Fisheries
Report No.
547 Reference
papers
Reduction Comment
Northwest Pacific 61 9 131 752 4 000 000 Matsuoka,
Zhou and Ye -5 131 752
Northeast Atlantic 27 3 671 346 2 791 080 Smith -780 266 Report No. 547 estimate
excludes Norway.
Estimated total discards
less than in Report No.
339. There are major
differences in the source
of discards
100 000
Norway
(current
study)
West Central Pacific 71 2 776 726 1 200 000 Harris, Chee,
Zhou and Ye -1 576 726 Southeast Asian countries
(not directly equivalent
to Area 71 but difference
in order of magnitude
evident [Chee]). Shrimp
discards (1.34 million
tonnes) overestimated
by approx. 0.45 million
tonnes (Harris). Zero
discards in Chinese
fisheries (Zhou and Ye)
300 000
900 000
Southeast Pacific 87 2 601 640 n.a.
West Central Atlantic 31 1 600 897 n.a.
West Indian Ocean 51 1 471 274 n.a.
Northeast Pacific 67 924 783 734 069 Newton -190 714 Change in the fisheries
Southwest Atlantic 41 802 884 n.a.
East Indian Ocean 57 802 189 n.a.
East Central Pacific 77 767 444 n.a.
Northwest Atlantic 21 685 949 699 689 Duthie,
Kennelly 13 740
East Central Atlantic 34 594 232 185 956 Balguerías Shrimp and cephalopod
fisheries only
Mediterranean/Black Sea 37 564 613 n.a.
Southwest Pacific 81 293 394 n.a.
Southeast Atlantic 47 277 730 116 652 Nolan and
Yau -161 078
Atlantic Antarctic 48 35 119 n.a.
Indian Ocean Antarctic 58 10 018 n.a.
Pacific Antarctic 88 109 n.a.
Total Paper No. 339 (Alverson) 27 012 099 -7 826 796
Revised estimate derived from Report No. 547 (Tokyo) 19 185 303 Approximates the value
in SOFIA 1998

103
Annex C
Method
This annex provides:
• additional information on the structure of the discard database;
• support for assumptions regarding certain discard rates used in the database; and
• discussion on the problems of determining accurate estimates of discards, with
particular reference to discard sampling and raising or extrapolating the sample
estimate to the population (i.e. the fleet, species or fishery).
An accurate determination of bycatch and discard rates is important for fisheries
management. If the rates assumed for a fishery are too low, then TACs are likely to
be exceeded (Pacific Fishery Management Council, 2001). The long–term biological
stability and yield of the fishery may be affected and rebuilding strategies for depleted
stocks may not be successful. Chronic underestimation of fishing mortality places
the future economic benefits to the industry at risk through further depletion of
resources. If the bycatch and discard rates assumed for the fishery are too high, then
total mortality is overestimated and TACs may be set too low, which unduly restricts
fishing, resulting in less economic benefit to the industry.
C.1 DIAGRAMMATIC REPRESENTATION OF CATCH CONCEPTS
Figure 3 provides a diagrammatic representation of the catch concepts upon which the
FAO Fishstat statistical system is based.
C.2 DISCARD SAMPLING
Accurate estimates of discards depend on discard sampling and the subsequent raising
or extrapolation of the sample estimates to the entire population. Sampling discards and
raising of sample values to the species, fleet or fishery level pose numerous technical
difficulties that are briefly discussed below.
The complex nature of many discard investigations can make them costly in terms
of financial and human resources. Costs can prove prohibitive to many fisheries
administrations. A recent investigation into the discard and escape mortality of
Nephrops and roundfish from demersal trawls required the concerted efforts of six
different institutes and other parties from five different countries (Denmark, Norway,
Sweden, the United Kingdom and the United States), at a cost of 1.9 million euros
(Fisheries Technology Committee, 2000). Multivariate analysis of discard sampling data
may also provide insights into the design of management measures (Murawski, 1996).
Clarity regarding the purpose of sampling1 is essential for design of an effective
sampling protocol. If the discard estimates are to be used as an input to stock
assessments, then detailed information on parameters such as sex, weight, age, length,
maturity and fecundity may be required.
There are several approaches to estimating discarding in a commercial fishery:
• observers
• retention of discards by fishers
• questionnaires
• simulated commercial fishing
• modelling
• Delphi.
1 See ICES, 2000b (CM 2000/ACFM:11) for a comprehensive discussion; Hall, 1999.

Discards in the world’s marine fisheries – an update
104
Annex C – Method 105
FIGURE 3
Diagrammatic representation of catch concepts (FAO)
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Annex C – Method 105
C.2.1 Use of trained observers
Sampling of discards by observers is generally regarded as the most effective and
accurate method (Punt, 1999), but not if discarding is illegal.2 Many national authorities
and regional fisheries bodies (e.g. NAFO, ICES/EC, NEAFC, CCAMLR) make use
of observers for sampling of discards.
Observer programmes encounter a range of difficulties. Discards cannot be
assessed accurately where catches are slipped. Safety of observers at sea is a concern,
particularly if the vessel crew are “hostile”. In situations where there are a limited
numbers of observers and several fleets (vessel strata), there are problems in selecting
the vessels on which to place observers, as there is a need to cover all strata and in
particular the strata with the greatest inherent discard variability (Cotter et al., 2002).
Vessels also change gear on trips. Discard variability tends to be higher between trips
than between hauls or sets, requiring more trips rather than more fishing operations
to be sampled. Vessels are the primary sampling units and days and trips may prove
difficult to use for random sampling. In addition to the difficulties in designing discard
sampling programmes to reflect the variability in fleet characteristics, fisher behaviour
and the spatial and seasonal variation in fish distribution, some sampling may require
consideration of the diurnal variation in fish behaviour, placing additional burdens on
observers (van Beek, 1998).
Observer schemes are only useful for estimating total bycatch where there is also
an adequate measure of total fleet activity. Furthermore, observer schemes can only
provide a minimum estimate of bycatch (European Commission, 2002b). Even the
most vigilant observer will miss some events. Animals that are trapped in fishing gear
underwater, but then fall from the gear before it is hauled back to the boat, for example,
will almost never be counted. Observers must also be able to see the net or other gear
as it reaches the boat and access the catch as it is sorted. During the hours of darkness
this ability may be compromised, depending on lighting conditions, and this can also
lead to underestimation. If automatic sorters are used, the observer may never get a full
view of either the catch or the discards. Moreover, the presence of the observer may
alter the discard behaviour of the fishers.
2 The observer effect refers to a situation in which the fishing practices of a vessel differ in some significant
way when an observer is aboard. When this occurs, the observer–collected data are not representative of
the fishery as a whole.
BOX 10
Sampling difficulties encountered by observers
“Two fishing boats, even if similar outwardly, seldom process their catches in exactly the same way.
Fish pounds are of various shapes and sizes; fish may be picked out by hand or with a conveyor
belt; the whole catch may or may not be containerized initially; discards may be selected by eye or
by measurement; they may be tossed overboard immediately or accumulated and shovelled over in
one or more large lots; and the fish for landing may or may not be gutted and sorted. Discarded fish
can be mixed with varying quantities of marine weed, rubbish, etc. (’trash’) depending on grounds
and gear type, making sampling difficult. Sampling can also be constrained by the space and shelter
available for working, the weather, and by time. It is important that observers conduct their work
without unduly holding up the normal processing of fish for landing and marketing. A further time
constraint arises because, for safety, the observer should not usually remain on deck alone when the
crew have finished their work. For these reasons, samples often represent only a small proportion of
the catch, leading to sampling variance.”
From BIOECO 93/003 (Cotter, 1995), cited in ICES CM 2000/ACFM:11 (ICES, 2002b).

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Annex C – Method 107
A general impression obtained from the literature on discards is that insufficient
attention is devoted to discards of non–commercial invertebrate species, such as
echinoderms, tunicates, sponges and crabs. This may be because the primary focus of
observer reports is on commercial species or because of the notion that such invertebrates
are “rubbish”, “debris”, or of no interest. Even in regimes that prohibit discards,
allowance is made for discarding of non–commercial species (such as in Iceland).
Real discards are always higher than visual estimates made by experienced observers,
at times more than ten times higher (NAFO, 2000). However, observer reports are still
the most reliable3 means of determining levels of discards and bycatch, even though
the reports may reflect a minimum, rather than total level of discards. Where bycatch
quotas are managed at the vessel level, managers and owners quickly recognize the
potential consequences of biased sampling, and the sampling and estimation process
may receive greater scrutiny.4
The reply of NOAA/NMFS to Oceana
The reply of NOAA/NMFS to Oceana provides a valuable and comprehensive
summary of the issues relating to the sampling of bycatch and, by extension, the
sampling of discards (NOAA [Department of Commerce], 2003). The reply provides
a balanced discussion on the objectives, needs, priorities, coverage and costs of bycatch
sampling, with particular regard to the use of observers and the legal obligations on the
administration to provide accurate estimates of bycatch.
C.2.2 Logbooks and retention by fishers
Requiring or requesting fishers to record discards in logbooks can provide a valuable
source of discard information. For example, NAFO (NAFO, 2002) and NEAFC have
rules on logbook discard data.
BOX 11
Observer procedure in Canada’s northern shrimp fishery
“The established observer procedures, as outlined in the observer manual, for estimating regular
discard (broken shrimp) will be continued. However, these procedures will not be applied for
instances of significant highgrading of shrimp.
• The observer and the vessel captain will conduct independent determinations of bycatch and
discards. The observer will notify the captain immediately if bycatch/discards are of concern.
• The observer and the captain will record the bycatch/discards on a daily basis. These will be
recorded on the daily report form (copy attached).
• In the event of a disagreement between the reports of the observer and the captain, both parties
will document their findings on the daily report, which will become a part of the observer’s trip
report.
• The observer and the captain will seek to reconcile the difference. However, this does not imply
that the observer and the captain must agree.
• All such differences will be included in the observer’s trip report.
• The fisheries authorities’ Department of Fisheries and Oceans (DFO) will forward to the licence
holder a weekly summary of catches, bycatches, discards, etc. The DFO will supply the licence
holder with a copy of the observer’s trip report upon completion of the trip.”
3 A close correspondence (r2 = 0.8) between observer and logbook reports of discards was recorded in the
Hawaii longline fishery (Walsh, Kleiber and McCracken, 2002).
4 “Sample sizes are often small relative to catch sizes … and the random sampling requirement may be
compromised by vessel operations such that observers only have access to, for example, the first fish to
be spilled from the codend after the catch has been dumped.” From Karp et al, 2000.

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Annex C – Method 107
Comparison5 of discard information recorded by observers and in vessel logbooks
may enable the correction of vessel logbooks to provide improved estimates of discards.
While individual trip logbooks may not provide a high level of accuracy, discard rates
based on logbook data averaged across trips, tows or fleet may be closely correlated
with observer–based discard rates. If such a correlation can be shown, a correction
factor may be applied to the logbook data, which are generally shown to underestimate
discards.
Fishers may be asked (or paid) to collect, preserve and hold samples of discards
from their own catches. Scientific staff then process the samples when the vessel returns
to port. This approach may place a heavy reliance on the fisher to do the sampling
or respect the sampling protocol but may be more cost effective than observer
programmes (Lart, 2002).
C.2.3 Questionnaires and interviews
Responses to questionnaires may be inaccurate, or those fishers willing to complete
the questionnaires may bias the results. Interviews must be confidential, they require a
knowledgeable interviewer and a relaxed atmosphere, and they can be expensive. The
Delphi method is a subjective method using the accumulated experience of recognized
experts in the field. All approaches have mixed results.
C.2.4 Simulating commercial fishing
A research vessel or a chartered commercial fishing vessel is chartered and deployed
with gear similar to that used commercially. The level of discarding can be estimated
from the length distributions found in the catches by comparison with the length
distributions in landed commercial catches (Medley, 2001). It is necessary to assume
that fishing techniques successfully simulate those of commercial vessels and that
fishing is geographically and temporally representative of how the fleet fishes. Similar
inferences can be made from the composition of landings or even the size grades of
exports of different fleets fishing the same fishery (The Irish Skipper, 2003).
C.2.5 Modelling
Discards may be estimated using data for total landings by the fleet, knowledge of the
size selectivity of commercial fishing gear, and knowledge of the length distributions
of the fish population (Casey, 1996). The latter may come from a research vessel survey
using a small mesh trawl. This method may be helpful when no direct measures of
discarding can be obtained. Although many assumptions are inherent in the method,
no raising problems arise because modelling is applied to the total landings data. The
approach may not be suitable for the estimate of total discards, i.e. fish that are not
commercial and not length sampled, or for factory vessels. Models can also be of
considerable assistance in designing a more effective sampling protocol; in testing
discard reduction measures; and in replacing average discard rates with a more robust
interpretation of the variability (Helser, Methot and Hastie, 2002).
C.2.6 Sampling design, sampling strata and data storage
If the primary objective of discard sampling is to improve the catch estimates used for
stock assessments, it is advantageous to use the same sampling strata and to ensure
compatibility between landings and discard databases. Raised discards can then simply
be added to landings to give the total catch6 for that stratum.
5 Sampson (2002) shows that logbooks underestimated discards by approximately 20 percent, but that the
boat–to–boat variability can be high.
6 See tables prepared by ICES (2002).

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Annex C – Method 109
However, in practice, use of these strata for sampling discards is not necessarily
efficient. First, quantities of fish discarded are not necessarily proportional to
quantities landed, depending also, for example, on the size selectivity of the fishing
gear and the availability of quota to land a species. Second, it is possible to sample the
landings of several vessels during one visit to a port, but one discard sampling trip may
take two to three weeks. Third, the variability in discards is unlikely to be similar to
the variability in landings. Therefore, a statistically valid sampling scheme (Tamsett et
al., 1999; Allen et al., 2001) is likely to require different sampling strata and, to obtain
accurate estimates of discards, sampling effort must be designed to concentrate on the
levels of largest variability (Rochet et al., 2000; Allen et al., 2002). Furthermore, large
numbers of sampling strata are not practical for discard sampling with small numbers7
of observers, as in most European countries. In many sampling periods it simply will
not be possible for observers to sample trips from each of many strata. The result is that
unbiased estimation is made very difficult. Several other factors constrain establishing
standardized, at–sea sampling schemes for discards:
• high diversity of fleets in different countries;
• different levels of information available about these fleets (vessel lists, total effort,
etc.);
• different trip lengths (e.g. one day or 30 days);
• different observer resources (from two covering a long coastline, to all trips
observed, as in Canada); and
• to some extent, differences of opinion regarding the statistical framework and
theory suitable for discard surveys.
While many countries are embarking on new discard programmes there may not
be an effective system for the storage, retrieval and analysis of discard data. Logbook
information on discards often remains unanalysed. Considerable additional efforts are
required to establish statistically sound, cost–effective discard sampling protocols.
C.2.7 Transboundary stocks and fisheries
Transboundary stocks may require different approaches to sampling, particularly if
international quota stocks are involved. Among ICES8 members, the country of origin
generally makes arrangements to sample discards and associated landings. Observer
programmes in international fisheries pose particular problems regarding responsibility
for observers.
The country of landing
Observers in the country of landing often have difficulty in finding out when and
where a foreign vessel will be landing. This makes scheduling of the trips with their
main sampling programme for national vessels very difficult. Having successfully
boarded a vessel in the observer’s own home country, the observer may be disembarked
in another distant country and be faced with an expensive return journey. The observer
may have language difficulties on board. There may subsequently be difficulties
obtaining data from the foreign country to permit raising of results from the sampled
trip to the appropriate fleet. Alternatively, results may be sent to the foreign country
for their own use. Teams of observers tend to be so busy with sampling their own
national vessels that they are reluctant to sample for other countries. This could be
altered by making contractual arrangements, but the scheduling problem remains.
7 A 100 percent observer coverage is mandatory in several United States fisheries and in many industrial
fisheries in West and southern Africa, in Canada and in New Zealand.
8 Several paragraphs in this section of Annex C are quoted or adapted from ICES reports, e.g. ICES, 2002.

Discards in the world’s marine fisheries – an update
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Annex C – Method 109
The country of ownership
Observers are likely to have to travel both to and from the country of ownership. The
country of ownership may not have comprehensive lists of all the vessels owned (but
only those registered with them). Inclusion of all vessels in a sampling scheme may
therefore be difficult. The country of ownership is unlikely to have the information
necessary to raise trip results to the appropriate fleet level. Observers from the country
of ownership are likely to speak the same language as the crew.
The country of registration (flag country)
The flag country will have all available information about the vessel and will therefore
be in a good position to schedule sampling and raise trip results to the appropriate
fleet. Transportation and language problems are likely to arise for observers. However,
contracting the country of landing to undertake the sampling and to send back the data
for the trip may be practical, provided that sufficient notice is given.
International discard database
Baltic countries have established a common database (BALTCOM) which demonstrates
(ICES, 2002) the opportunities for holding discard data regionally. However, it is
necessary to assess carefully how such a database could be applied to regions other
than the Baltic. Possible problems are:
• difficulties in drawing boundaries between seas;
• fishers may disapprove of the level of disaggregation of the data, which may reveal
the identity of a vessel to fishing competitors or to enforcement agencies, even
though the name of the vessel itself is not stored. Fishers might withdraw their
cooperation with sampling activities as a result;
• national legislation on data privacy may constrain sharing of “raw” data;
• national sampling authorities may claim intellectual property rights over some
data or fail to contribute required information for other reasons, e.g. concern that
national quotas may be reduced;
• different types of fishing vessels, discard sample surveys and data raising methods
in each region may cause significant computational problems; and
• linking of discards and landings data in one database, if thought desirable, could
cause various technical difficulties in each region.
C.3 RAISING OF DISCARD ESTIMATES
Raising factors are required to convert sample results for individual catches, trips or
vessels to estimates of discarding by the total fleet or fishery over a given sampling
period, e.g. one year. The design of sampling protocol is highly relevant to the raising
of discard data. Raising of results for a trip to an estimate for a fleet may utilize the
number of vessels in the fleet, the total effort or the total landings. Whichever factor is
selected, reliable data must be available to fit the chosen sampling strata. For example,
a fishery with a defined gear type (or mesh size) as a sampling stratum should have
matching landings (catch) declarations.
One common way to establish the fleet estimate is to raise the quantity of discards in
a sample of a catch to an estimate of the discards in the total catch, then to extrapolate
from the individual catch to the trip, from the trip to the vessel, and finally from the
vessel to the fleet. Quantities may be recorded as weights or numbers of fish. Estimates
of discards based on the mean of individual tows appear to overestimate discards. Using
the sum of the discard weights and landing weights from all sampled hauls has been
shown to give a more accurate estimate of discard rates (Allain, Biseau and Kergoat,
2003). Common raising methods9 include those:
9 For further discussion see ICES, 2000b.

Discards in the world’s marine fisheries – an update
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Annex C – Method 111
• by landings (or catch)
• by number of vessels
• by number of trips
• by trips per vessel and number of vessels (two step)
• by other measures of effort, e.g. hauls, 1 000 hooks
• by probability of sampling;
• by strata
• in accordance with a model.
Each approach has its advantages and disadvantages and each is based on assumptions
regarding the relationship between discards and parameters recorded during sampling.
In most cases the assumption is that this relationship is linear. This is the assumption
that has been used in raising discards to fishery level in the discard database. However,
in some fisheries it is suggested (Rochet, Péronnet and Trenkel, 2002) that there is no
auxiliary variable upon which discards can be accurately projected, i.e. sampling is
essential to determine discards. The absence of a coherent theory upon which discards
can be forecast suggests that no one method can currently be judged as the superior for
all fisheries (Trenkel and Rochet, 2001).
Problems with estimates
A comparison between raised retained quantities and officially reported landings
may reveal substantial anomalies, which may have consequences at a political level.
Autoconsumption and illegal landings may account for substantial unreported catches.
The use of unreliable landings records to raise discard estimates may render these
estimates inaccurate. As many national fisheries statistics are not readily available by
fleet, by gear or by fishery, discard information may be difficult to raise to the fleet or
fishery level. There may be significant differences between effort–based and landings–
based discard estimates, particularly with regard to the incidence and quantity of
discards of shoaling species in trawl fisheries (Walmsley, Leslie and Sauer, 2003; Trenkel
and Rochet, 2001).
C.4 DISCARD DATABASE FILE STRUCTURE
The database file structure is given in Table 33. Access to and use of the discard database
will be determined by FAO.
C.5 ASSUMPTIONS REGARDING DISCARD RATES
Most small-scale and artisanal fisheries in developing countries have been allocated
a discard rate of either 0.5 or 1 percent, as a zero discard rate was considered to be
unrealistic for some artisanal fisheries. The rate assigned to a particular fishery is based
on additional information from the country, the region or fisheries assumed to be
similar.
Certain highly selective fisheries have been assigned a zero discard rate based on
the available literature, contacts with experts and the author’s own experience. These
fisheries include diver fisheries for abalone, sea urchins, lobster; squid jig fisheries and
artisanal troll fisheries. Some of the supporting evidence is presented in Table 35.

Discards in the world’s marine fisheries – an update
110
Annex C – Method 111
TABLE 33
Description of the discard database fields
Code Description of field Notes/comments
FAOA FAO area code Sometimes difficult to assign the fishery to an FAO area, e.g.
South China Sea
LMESP Large marine ecosystem code Not inserted as yet (several uses foreseen)
SA1 Type of sub-area For example, ICES will also insert other FAO sub-area codes
SA1C Sub-area code For example, IV for Irish Sea, CECAF 34.3.2. for Cape Verde
insular
SA2 Second sub-area For example, name of RFMO – ICCAT
SA2C Second sub-area code For example, RFMO code, e.g. ICCAT 22 = Brazil, etc.
Country Name of country Standard UN/FAO name (check); can be a group of countries
(e.g. “all ICCAT members”)
FFishery, usually a function of the
available information
Text description of fishery. Not all entries are “fisheries”
as, for example, total catch is sometimes given for a small
country in absence of other information (or as check)
Main species Target species Species names as in bibliog. ref., e.g. “bonga”, “peixe pedra”;
at times “multispecies”
GGear name from the bibliographic
reference
For example, trawl, gillnet, matanza, basnigan, “multigear”
sometimes used
L/C
Flag indicating landing (L) or catches
(C) – rarely. Coded “N” when referring
to numbers in incidental catches
(marine mammals, seabirds, etc.)
Major problems in determining exact nature of quantities,
nominal landings or catch.
TAC is used if no other information available. The source
material is often unclear as to whether the value described as
“catch” is landing, nominal catch or gross catch
Yr Year to which the L/C refers Sometimes average used if time series available
LCTonnes Landings in tonnes; incidental catches
in numbers See L/C above; numbers used with regard to seabirds, etc.
RefT Bibliographic reference/source of
tonnage information
Main discards Species or species groups as described
in source material
Substitute with FAO codes/insert extra code field; some
species names in local language
Discard rate Discards as % of total catch (landings
+ discards)
Direct from source material or calculated from information in
reference; at times assumed
Dtonnes Tonnes of discards
Direct from reference material or calculated from information
in reference, e.g. shrimp: bycatch ratio and % of bycatch
discarded
Basis Note on basis for discard calculation For example, observers, survey, applied discard rate from
adjacent country, assumed/similar fishery
RefD Bibliographic reference for discard
information
RefYr Reference year for discard information Important because of changing regulations, e.g. obligation to
use square mesh from 1999
Reason Reason for discards Field often not completed, D = discretionary, R = regulatory,
H = highgrading, etc.
Measures Notes on measures applied For example, TEDs obligatory, BRDs used, obligation to land
...% of bycatch, no-discard policy
Exp Status of the fishery Fully exploited, overexploited, etc.; check conforms to FAO/
national classification
Other
comment Any other comments
LIFDC Low income food deficit country Flag – may be used in later analysis; data available partly
inserted
PerCap Per capita fish consumption To obtain from FAO Fishstat, may be used in later analysis
ProSpec Protected species Flag – separate lines inserted and flagged with P
XtraWkSheet Reference to additional worksheet
(country.xls)
Flag – refers to subsidiary sheets for certain countries/fisheries
where discard data in the source material were transformed
to discard database format
DT Discard total Flag – records selected for calculation of total discards
D Double counting Flag – indicates possible/probable source of double counting
SS Small-scale fishery Flag – indicates small-scale fisheries
Country code Field not in spreadsheet as yet Standard UN/FAO code to be inserted
Species code Field not in spreadsheet as yet Use standard FAO code – species/species group/family, etc.
ISSCFG Field not in spreadsheet as yet International fishing gear classification code ISSCFG – to be
inserted (note other class, e.g. United States)

Discards in the world’s marine fisheries – an update
112
Annex C – Method 113
Albania 1
Algeria 4
American Samoa 1
Angola 12
Anguilla 1
Antigua and Barbuda 1
Argentina 48
Aruba 1
Australia 39
Bahamas 2
Bahrain 5
Bangladesh 9
Barbados 8
Belgium 4
Belize 1
Benin 2
Bermuda 1
Brazil 62
British Virgin Islands 1
Brunei Darussalam 4
Bulgaria 1
Cambodia 12
Cameroon 6
Canada 50
Cape Verde 5
Cayman Islands 1
Chile 61
China 36
Colombia 3
Comoros 1
Congo 1
Cook Islands 1
Costa Rica 5
Côte d’Ivoire 3
Croatia 1
Cuba 2
Cyprus 3
Denmark 25
Djibouti 1
Dominica 1
Dominican Republic 2
Ecuador 1
Egypt 9
El Salvador 5
Equatorial Guinea 1
Eritrea 5
Estonia 4
European Union 7
Faeroes 8
Falklands/Malvinas 12
Fiji Islands 1
Finland 7
France 34
France (Mayotte) 1
France (Réunion) 4
French Guiana 4
French Polynesia 1
Gabon 2
Gambia 2
Gaza strip/Palestine 1
TABLE 34
Number of records by country or area
Georgia 1
Germany 10
Ghana 5
Greece 7
Grenada 1
Guadeloupe 1
Guam 1
Guatemala 4
Guinea 6
Guinea–Bissau 7
Guyana 6
Haiti 2
Honduras 1
Iceland 20
India 18
Indonesia 13
Iran, Islamic Rep. 4
Ireland 24
Israel 5
Italy 5
Jamaica 2
Japan 53
Jordan 1
Kenya 2
Kiribati 1
Korea, Dem. Rep. 4
Korea, Rep. 32
Kuwait 3
Latvia 4
Lebanon 1
Liberia 4
Libyan Arab Jamahiriya 5
Lithuania 1
Madagascar 5
Malaysia 60
Maldives 9
Malta 4
Marshall Islands 1
Martinique 1
Mauritania 8
Mauritius 3
Mexico 44
Micronesia, Fed. States 1
Montserrat 1
Morocco 27
Mozambique 7
Multiple countries 99
Myanmar 9
Namibia 17
Nauru 1
Netherlands 6
New Caledonia 1
New Zealand 7
Nicaragua 7
Nigeria 3
Niue 1
Norfolk Island 1
Northern Mariana Islands 1
Norway 57
Oman 6
Pakistan 11
Palau 1
Panama 3
Papua New Guinea 2
Peru 31
Philippines 34
Pitcairn Islands 1
Poland 5
Portugal 20
Puerto Rico 1
Qatar 1
Romania 1
Russian Federation 61
Saint Helena 1
Saint Kitts and Nevis 1
Saint Lucia 1
Samoa 1
Sao Tome 2
Saudi Arabia 9
Senegal 13
Seychelles 2
Sierra Leone 4
Slovenia 1
Solomon Islands 1
Somalia 3
South Africa 31
Spain 18
Sri Lanka 12
Sudan 4
Suriname 7
Sweden 9
Syrian Arab Republic 2
Taiwan Province China 18
Tanzania, United Rep. 2
Thailand 24
Timor-Leste 1
Togo 1
Tokelau 1
Tonga 1
Trinidad and Tobago 12
Tunisia 8
Turkey 18
Turks and Caicos Islands 1
Tuvalu 1
Ukraine 1
United Arab Emirates 1
United Kingdom 36
United Kingdom (British
Indian Ocean Territory) 1
United States 136
Uruguay 15
Vanuatu 1
Venezuela 17
Viet Nam 15
Wallis and Futuna Is. 1
Yemen 7
Yugoslavia/Serbia and
Montenegro 1
Total 1 791
Note: not all records contain discard information. The number of records is an indication of the number of fisheries
recorded.

Discards in the world’s marine fisheries – an update
112
Annex C – Method 113
TABLE 35
Supporting evidence for low or negligible discard rates in certain fisheries
Area Comment/fishery Source
Small–scale and artisanal fisheries
Morocco “… considered non–existent, since local fishers sold or
consumed the total catch”
Baddyr, 1989
Cameroon “… there are no discards in artisanal fisheries. In Cameroon,
even the immature fish is used so there is nothing to be
discarded at all”
O. Njifonjou, pers. comm.
Senegal “… no discards in artisanal fisheries” CRODT, pers. comm.
Mozambique “… insignificant in artisanal fisheries” IDPPE, Maputo
Pacific Islands “… statistically not distinguishable from zero” T. Adams (SPC), pers. comm.
Samoa “… very rare” A. Wright (SPREP), pers. comm.
Caribbean
Islands
“Negligible” Chief Fisheries Officer, Saint Lucia;
FAO Regional Fisheries Officer
Myanmar “… discards are negligible in artisanal fisheries” Myanmar Fisheries Federation, 2003,
pers. comm.
Other fisheries and countries
Eastern Central
Atlantic
“… discards have never been assessed but are supposedly
negligible”
Balguerías, 1997
Sri Lanka “… no discards in Sri Lanka fisheries as all fish landings are
utilized for human consumption”
A. Hettiarachchi, Director–General,
pers. comm.
Thailand “… we make use of everything” SEAFDEC
Cambodia “… there are no discards” Delegate to COFI, 2003
Viet Nam “… we do not collect information on discards as discarding is
not of concern. Discards are low or negligible”
Delegate to COFI, 2003
Malaysia “… not common in Malaysian capture fisheries” … “trash fish
… is being used as fishmeal by the aquaculture industry”
bin Nuruddin, (2003), Samut Prakan
workshop
Malaysia and
Thailand
“RSW [refrigerated seawater] systems … allowed nearly all
the bycatch to be kept on board” … “… quantum of discards
expected to decrease”
Chee, 1997
Indonesia “Very low in all fisheries except the Arafura Sea trawl
fishery.” … “Negligible in most artisanal fisheries”
P. Martsubroto (FAO), pers. comm.
L. Engvall, pers. comm.
China “Although much of this catch is low market, none is
discarded.” … “Discarding is not believed to exist any more”
“We use everything … some discards in the long-range trawl
fishery in the South China Sea”
“All species are targets”
Zhou and Ye, 1997
China delegate to COFI, 2003
Ministry, 2003, pers. comm.
India “very very low”
“1–2%.” … “India imports large quantities of animal feed”
Ministry, Delhi, pers. comm.
MPEDA, Kochi, pers. comm.
South Africa,
Japan, other
Zero discards in squid jig fisheries Japp, 1997
South Africa Zero discard rate in abalone diver fisheries Japp, 1997
Cape Verde Lobster diver fishery Ministerio do Mar
Mauritania Octopus pot fishery DSPCM
Senegal Kayar linefish Fisheries inspector
Celtic Sea/Biscay Tuna pole and line Melnychuk et al., 2001
Norway Mackerel troll Valdemarsson and Nakken, 2002
Fishmeal fisheries
Peru “… discards estimated to represent <5% of total landings” IMARPE (R.G. Carrasco), pers. comm.
Denmark (Baltic) “… no, or minor discards … impossible to sort … discards in
these fisheries are negligible”
ICES, 2000a
Morocco >5% caused by net damage (coastal sardine used for food and
fishmeal)
“… insignificant” (industrial pelagic vessels)
Haddad, 1994
Iceland Blue whiting caught for fishmeal Fishing News International, 2003
CECAF region Russian pelagic midwater trawlers for small pelagics (targeted
as food fish, not for fishmeal). “… bycatch entirely processed
to fishmeal ... insignificant discards of invertebrates only”
N.M. Timoshenko, pers. comm.
South Africa Purse seine and midwater – minor regulatory discards only Japp, 1997
Black Sea Fishmeal plant capacity is greater than supply of anchovy Fisher cooperative, Trabazon, pers.
comm.
Scotland Argentine and blue whiting fishery Pierce et al., 2002
Norway Industrial fishing 1–2.4% discard Valdemarsson and Nakken, 2002
Baltic Swedish herring and sprat trawl ICES, 2000a

115
Annex D
Summary of the reasons for
discards
D.1 CAUSES OF DISCARDS
A clear understanding of the reasons for discarding is necessary in order to change
discarding practices and help design sampling and raising protocols. A basic
classification of the catch may be made into: (i) fish (species/sizes/sex) always retained;
(ii) fish always discarded; and (iii) fish partially/occasionally discarded. The reasons for
the discards are likely to vary by type of fish and discard reduction efforts may be most
effectively focused on fish that are partially discarded.
D.2 CAUSAL DIAGRAM AND DECISION FRAMEWORK
D.2.1 Evaluation of bycatch
Figure 5 presents the causes and consequences of discarding.
Adapted from Horsten and Kirkegaard, 2002.
FIGURE 4
Evaluation of bycatch

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

Discards in the world’s marine fisheries – an update
116
Annex D – Summary of the reasons for discarding 117
TABLE 36
A classification of causes of discards
Cause/parameter Comment/examples/trends
Biological
Species composition High species diversity is likely to increase untargeted species harvested. Changes in the
species composition in fisheries may increase or decrease discards and may be directly
linked to overfishing. Changes in discarding practices are likely to be related to change in
the proportion of target species
Year class Large juvenile year class may increase discards
Exploitation status
(overfishing)
Overfishing may result in a larger proportion of smaller fish in the catch and large
discards of juveniles or fish under the MLS; low stock density of target species may lead to
increased fishing effort and unwanted bycatch
Sex Target is roe fish only, immature/male fish may be discarded
Poisonous/dangerous For example, landings of Lujanus bohar are prohibited in Réunion; stingrays
Vessel characteristics
Size of fish hold Bycatch may occupy space designated for target species
Freezing capacity Quality of more valuable target species may suffer; insufficient freezing capacity; different
freezing duration for shrimp and bycatch, for example
Limited ice on board Quality of target species may suffer if ice is used for bycatch
Catch quantity If catches are large, then discards may be higher
Processing plant Catches exceed capacity of plant (e.g. surimi plant, fishmeal plant). Small/very large sizes
cannot be handled by filleting machines
Catch composition Small sizes, damaged fish, impossible to sort (small pelagics)
Fishing operations
Skipper Payment mechanism, personal preferences, skills
Selectivity Wide range of effects on target species and bycatch
Crew remuneration Payments linked to bycatch recovery, or not
Trip length Discards higher at start of long trip
Haul length Discards may be higher if trawl haul time is long, because of damage to fish
Soak time Discards higher with long soak time because of damage to fish, e.g. Celtic Sea French
gillnets
Time of trip Differences in fish behaviour day/night /tides, e.g. Nephrops North Sea; discards may be
higher at the start of a trip
Fishing area Some areas known to have high concentrations of juveniles/unmarketable fish/predators
(line fisheries)/jellyfish
Fishing season Restrictions often applied to avoid large unwanted catches of juveniles
At–sea transfer Payment, theft of target catch
Gear
Rigging of gear May have a major influence in trawl and longline fisheries, e.g. chafers
BRDs Major effect in some fisheries, e.g. in Norway, in NAFO, square mesh panels in Nephrops
trawls, numerous Australian trawl fisheries
Hook/line type/bait Related to mouth, feeding behaviour and fishing depth, e.g. tuna/shark
Mitigation measures Assessment of effectiveness difficult because of low incidental catch rates
Selectivity Gear characteristics may not be in harmony with regulations, e.g. MLS
Market
No/poor market for bycatch Common in many fisheries, e.g. Guianas shrimp, Mozambique shrimp. Uneconomical to
freeze low–value bycatch
Damaged fish For example, crushed in the codend, decomposed, shark damaged
Taboos, customs Low or non–consumption of shark in Jamaica
Bycatch retention reduces
value of target species
Use of crew time for sorting, reduced efficiency of freezers, cold store efficiency
compromised
Highgrading Common in many quota fisheries (e.g. EU, United States)
Poor economic performance May result in retention of more bycatch to cover costs (marginal profitability). May also
result in reduced fishing effort and reduced discards
Regulatory
Licensing Fishing licence may restrict catch/landings to certain species
Observer effect Presence of observer may result in greater retention of bycatch, increased discards (e.g. if
the observer is monitoring quotas), or increased reporting of discards
Highgrading/quotas Common where quotas are strictly enforced
Target species as % of
landings
May result in “discards” or disposal of non–target species after landing, i.e. bycatch
retention only until landing and subsequent dumping, e.g. France
MLS The less selective the gear the higher the discards
Bycatch quota Requires effective enforcement, probably by observers and possibly retention of bycatch
Time/season Effective in reducing bycatch and discard of juveniles
Level of enforcement All regulatory discards are closely related to the level of enforcement or fishing
community peer pressure

Discards in the world’s marine fisheries – an update
116
Annex D – Summary of the reasons for discarding 117
FIGURE 5
Causal diagram of discards
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

 












 




















  
 

















  

 

Discards in the world’s marine fisheries – an update
118
D.2.2 Discard decision framework (United Kingdom)
Adapted from Lart, 2002.
FIGURE 6
Discard decision framework (United Kingdom)
















 













 






















 






































119
References
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