Technical ReportPDF Available

Ireland Red List No. 11: Cartilaginous fish [sharks, skates, rays and chimaeras]

Authors:
  • Killybegs Fishermens Organisation
  • National Biodiversity Data Centre, Ireland
Ireland
Red List No. 11
Cartilaginous fish
[Sharks, skates, rays
and chimaeras]
1
Ireland Red List No. 11:
Cartilaginous fish [sharks, skates, rays and chimaeras]
Maurice Clarke1, Edward D. Farrell2, William Roche3, Tomás E. Murray4, Stephen Foster5 and
Ferdia Marnell6
1 Marine Institute
2Irish Elasmobranch Group
3Inland Fisheries Ireland
4National Biodiversity Data Centre
5Marine and Fisheries Division, Department of Agriculture, Environment and Rural Affairs
6 National Parks & Wildlife Service
Citation:
Clarke, M., Farrell, E.D., Roche, W., Murray, T.E., Foster, S. and Marnell, F. (2016) Ireland Red List
No. 11: Cartilaginous fish [sharks, skates, rays and chimaeras]. National Parks and Wildlife Service,
Department of Arts, Heritage, Regional, Rural and Gaeltacht Affairs. Dublin, Ireland.
Cover photos: From top: Thornback ray (Raja clavata) © Sytske Dijksen; Rabbitfish (Chimaera
monstrosa) © Ed Farrell; Lesser-spotted dogfish (Scyliorhinus canicula) © Sytske Dijksen.
Ireland Red List Series Editors: F. Marnell & B. Nelson
© National Parks and Wildlife Service 2016
ISSN 2009-2016
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CONTENTS
EXECUTIVE SUMMARY ..................................................................................................................... 4
ACKNOWLEDGEMENTS ................................................................................................................... 4
INTRODUCTION ................................................................................................................................ 5
Red list assessment methodology............................................................................................ 5
Red list categories & criteria ..................................................................................................... 6
Geographic and Taxonomic scope ........................................................................................... 7
Workshops and data collation ................................................................................................ 12
Aims ............................................................................................................................................ 13
SUMMARY OF FINDINGS ................................................................................................................ 14
Comparison with other Red Lists .......................................................................................... 15
Threats to cartilaginous fish in Irish waters ........................................................................ 16
Management and conservation actions ................................................................................ 17
Current and future research priorities .................................................................................. 22
SPECIES ACCOUNTS ....................................................................................................................... 23
OCEANIC AND PELAGIC SPECIES .................................................................................................. 24
Lamna nasus (Bonneterre, 1788) ............................................................................................. 24
Cetorhinus maximus (Gunnerus, 1765) ................................................................................. 26
Galeorhinus galeus (Linnaeus, 1758) ..................................................................................... 28
Prionace glauca (Linnaeus, 1758) ........................................................................................... 30
SHELF AND COASTAL SPECIES ...................................................................................................... 33
Squatina squatina (Linnaeus, 1758) ....................................................................................... 33
Rostroraja alba (Lancepède, 1803) ......................................................................................... 34
Dipturus batis complex A (= flossada) (Linnaeus, 1758) ................................................. 36
Dipturus batis complex B (= intermedia) Parnell, 1837 ................................................... 39
Squalus acanthias Linnaeus, 1758 .......................................................................................... 42
Raja undulata Lancepède, 1802 .............................................................................................. 44
Dasyatis pastinaca (Linnaeus, 1758) ..................................................................................... 46
Dipturus oxyrinchus (Linnaeus, 1758) ................................................................................... 47
Leucoraja naevus (Müller and Henle, 1841) ......................................................................... 49
Leucoraja circularis (Couch, 1838) ......................................................................................... 51
Leucoraja fullonica (Linnaeus, 1758) ..................................................................................... 53
Tetronarce nobiliana Bonaparte, 1835 ................................................................................... 55
Raja brachyura Lafont, 1873 ................................................................................................... 56
Scyliorhinus stellaris (Linnaeus, 1758) .................................................................................. 58
Raja microocellata, Montagu, 1818 ....................................................................................... 60
Raja montagui Fowler, 1910 .................................................................................................... 62
Raja clavata Linnaeus, 1758 ................................................................................................... 64
Mustelus asterias Cloquet, 1821 ............................................................................................. 66
Scyliorhinus canicula (Linnaeus, 1758) ................................................................................. 68
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DEEPWATER SPECIES ...................................................................................................................... 70
Centroscymnus coelolepis Barbosa du Bocage and de Brito Capello, 1864 .................... 70
Centrophorus squamosus (Bonnaterre, 1788) ....................................................................... 71
Centroselachus crepidater (Barbosa du Bocage and de Brito Capello, 1864) .................. 73
Dalatias licha (Bonneterre, 1788) ........................................................................................... 75
Deania calcea (Lowe, 1839)...................................................................................................... 77
Hexanchus griseus (Bonneterre, 1788) .................................................................................... 79
Etmopterus princeps Collett, 1904 .......................................................................................... 80
Apristurus manis (Springer, 1979) .......................................................................................... 82
Apristurus melanoasper Iglesias, Nakaya and Stehmann, 2004 ....................................... 83
Apristurus microps (Gilchrist, 1922) ...................................................................................... 85
Scymnodon ringens Barbosa du Bocage and de Brito Capello, 1864 ................................ 86
Oxynotus paradoxus Frade, 1929 ............................................................................................ 88
Dipturus nidarosiensis (Storm, 1881) ..................................................................................... 89
Neoraja caerulea (Stehmann, 1976)........................................................................................ 91
Chimaera opalescens Luchetti, Iglesias and Sellos, 2011 ................................................... 93
Malacoraja kreffti Stehmann, 1977........................................................................................ 94
Chimaera monstrosa Linnaeus, 1758 ..................................................................................... 96
Rhinochimaera atlantica Holt and Byrne, 1909................................................................... 97
Hydrolagus mirabilis (Collett, 1904) ...................................................................................... 99
Apristurus aphyodes Nakaya and Stehmann, 1998 ........................................................... 100
Apristurus laurussonii (Saemundsson, 1922) ..................................................................... 102
Centroscyllium fabricii (Reinhardt, 1825) ........................................................................... 104
Galeus melastomus Rafinsesque, 1810 ................................................................................ 105
Galeus murinus (Collett, 1904) .............................................................................................. 107
Etmopterus spinax (Linnaeus, 1758) .................................................................................... 108
Rajella fyllae (Lütken, 1887) ................................................................................................. 110
Rajella kukujevi (Dolganov, 1985) ....................................................................................... 112
Rajella bathyphila (Holt and Byrne, 1908) ......................................................................... 113
Amblyraja jenseni (Bigelow and Schroeder, 1950) ............................................................ 114
Bathyraja pallida (Forster, 1967) .......................................................................................... 116
Rajella bigelowi (Stehmann, 1978) ...................................................................................... 118
Bathyraja richardsoni (Garrick, 1961) ................................................................................. 119
Harriotta raleighana Goode and Bean, 1895 ...................................................................... 121
Hydrolagus affinis (de Brito Capello, 1867) ....................................................................... 122
Hydrolagus pallidus Hardy and Stehmann, 1990 .............................................................. 124
REFERENCES .................................................................................................................................. 126
APPENDIX 1 SUMMARY OF THE CRITERIA USED TO EVALUATE THREAT CATEGORY ......... 140
APPENDIX 2 RED LIST STATUS OF CARTILAGINOUS FISH SPECIES IN IRELAND ................ 141
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EXECUTIVE SUMMARY
A first Red List of cartilaginous fish (sharks, skates, rays and chimaeras), showing risk of
extinction, is presented for Irish waters.
Of the cartilaginous fish occurring in Irish waters, 58 were assessed using the latest IUCN
categories.
Of these, 6 were assessed as Critically Endangered: Portuguese dogfish Centroscymnus
coelolepis; common (blue) skate Dipturus batis (= flossada); flapper skate Dipturus intermedia;
porbeagle shark Lamna nasus; white skate Rostroraja alba and angel shark Squatina squatina.
A further 5 species were assessed as Endangered: leafscale gulper shark Centrophorus
squamosus; basking shark Cetorhinus maximus; common stingray Dasyatis pastinaca; undulate
skate Raja undulata and spurdog Squalus acanthias.
An additional 6 species were assessed to be Vulnerable: longnose velvet dogfish Centroselachus
crepidater; kitefin shark Dalatias licha; tope Galeorhinus galeus; shagreen ray Leucoraja fullonica;
longnose skate Dipturus oxyrinchus and cuckoo ray Leucoraja naevus.
Of the remaining species, 19 were assessed as Near Threatened and 22 species as Least
Concern.
The main anthropogenic impacts on threatened species are over-exploitation by commercial
fisheries and habitat destruction and disturbance.
There are no longer any directed fisheries for any threatened cartilaginous fish in Irish waters.
However threatened species are taken as by-catch in several fisheries, involving both Irish and
non-Irish vessels. Similarly, endangered and threatened species that straddle Irish and non-
Irish waters are caught by fleets further afield.
ACKNOWLEDGEMENTS
We thank An Coiste Téarmaíochta, Foras na Gaeilge for revision and provision of Irish names for
all species. David Stokes, Graham Johnston and Robert Bunn (Marine Institute) are acknowledged
for provision of data and expert judgement. Peter Tyndall (Bord Iascaigh Mhara), Noirín Burke
(Galway Atlantaquaria) and Declan Quigley (Sea Fisheries Protection Authority) provided
specialist information on certain species. The Irish Specimen Fish Committee provided data on
specimen and record fish. Pieter-Jan Schön (Agri-Food & Biosciences Institute) and the Centre for
Environmental Data and Recording provided extensive data for Northern Irish waters. Emmett
Johnston (Irish Basking Shark Study Group) and Simon Berrow (Irish Whale and Dolphin Group)
kindly provided validated basking shark data recorded by their members.
5
INTRODUCTION
Sharks and their relatives are collectively termed chondrichthyan, or cartilaginous, fishes. They
represent one of the oldest and most ecologically diverse vertebrate lineages with c.1,115 described
species worldwide. The group arose at least 420 million years ago and rapidly diversified to
occupy the upper tiers of aquatic food webs (Kriwet et al., 2008). Despite being one of the most
speciose groups of predators on earth, they include some of the latest maturing and slowest
reproducing of all vertebrates, resulting in very low population growth rates with little capacity to
recover from overfishing and other threats such as pollution or habitat destruction (Compagno et
al., 2005).
Irish waters contain 71 cartilaginous fish species, over half of the European list, and about 7% of
the worldwide total, encompassing a broad range of sharks, rays, dogfishes and rabbitfishes. The
Irish region has species occurring in every habitat, from coastal waters to deep-sea and it supports
both sedentary and highly migratory taxa. Irish waters are of key importance to many of these
species, hosting critical spawning and/or nursery aggregations. Moreover, these waters are the
focus of some of the most intense fishing effort in Europe.
Cartilaginous fish have received attention in Irish waters since the 19th century. Indeed some of the
initial descriptions of deepwater species were completed by Ernest Holt in his pioneering research
surveys on the R.V. Helga (e.g. Holt and Byrne, 1909), while Kennedy (1954) documented various
aspects of the ecology of more popular angling species. However it was not until the late 1980s that
the impacts of fishing were first considered, through the work on rays and spurdogs (e.g. Fahy,
1988; 1989). Around this time, the International Council for the Exploration of the Sea (ICES)
convened its first elasmobranch working group, in Dublin, and by 2005 ICES provided the first
population assessments of most of the important commercially exploited species (ICES, 2005; 2014).
Another very important research programme, which was initiated by the predecessors of Inland
Fisheries Ireland in 1970 and is still ongoing, was the tagging study of sharks and rays (Fitzmaurice
et al. 2003a-f). In addition to the more common species this programme still provides the only
information on some of our very rare species. The Irish Specimen Fish Committee (ISFC) has been
recording the distribution and weights of rod-caught ‘specimen’ and record fish, including the
more common chondrichthyan species, since 1955 (ISFC, 2014).
Red list assessment methodology
The International Union for the Conservation of Nature (IUCN) coordinates the Red Listing
process at the global level and also at the European level (e.g. Temple & Cox, 2009; Cox & Temple,
2009). However, individual countries and regions are encouraged to produce their own Red Lists,
and the IUCN have published guidelines on the application of the Red Listing criteria and
categories at the regional level to facilitate this (IUCN, 2003).
The first Irish Red Data Book was published in 1988 and covered vascular plants (Curtis &
McGough, 1988). In 1993, the second Irish Red Data Book brought together information on
Ireland’s threatened vertebrates: mammals, birds, amphibians and fish (Whilde, 1993). These
publications took several years to prepare and were costly to print. In recent years the emphasis in
Ireland and elsewhere has changed to the production of Red Data Lists. Although subject to the
same rigorous assessment procedures (IUCN, 2001, 2003, 2012a, 2012b) the focus has been on
making the ensuing publications available online, rather than in hard copy. This has allowed a
6
faster turn around as evidenced by the recent sequence of new Red Lists for Ireland (Marnell et al.,
2009; Regan et al., 2010; King et al., 2011; Nelson et al., 2011; Lockhart et al., 2012; Wyse Jackson et al.,
2016). Progress has also been made on revising and updating the original Red Data Books; a new
Red List of terrestrial mammals was published in 2009 (Marnell et al., 2009) and the current volume
updates elements of Whilde’s (1993) assessments of fish.
Red list categories & criteria
The IUCN Red List Categories and Criteria are intended to be an easily and widely understood
system for classifying species at high risk of global extinction. The general aim of the system is to
provide an explicit, objective framework for the classification of the broadest range of species
according to their extinction risk (IUCN, 2001). Adoption of the IUCN system also ensures
consistency across taxonomic groups and regions.
Although initially developed to assess risk of global extinction, more recently the IUCN have
provided guidance on how to apply the red list categories and criteria on a regional level (IUCN,
2003). Assessments for a geographically defined sub-global area assist in conservation
prioritisation at a regional level.
Various versions of the IUCN system have been in use for over 40 years, but since the late 1990s the
categories and criteria have undergone an extensive review to produce a clearer, widely applicable,
open, and easy-to-use system. Consequently, the categories used by Whilde (1993) are no longer
applicable although some comparison is possible. For the purposes of the current assessment the
additional category of Regionally Extinct was included, as recommended by the IUCN regional
guidelines (IUCN, 2003). This category was not used in the 1993 assessment. The full list of
categories used in this assessment is given in Figure 1.
The IUCN guidelines provide five criteria against which species data is assessed (IUCN, 2012b; see
Appendix 1). In order to complete the red list, each species was evaluated systematically against
each criterion A-D. Criterion E was not used, as sufficient data for a fully quantitative assessment
was not available for any of the species under study. Where a species met any one of the criteria it
was noted, and the highest level of threat achieved by a species became its qualifying category. All
of the criteria met at the highest level of threat were listed for each species.
The IUCN guidelines recommend assessors adopt a precautionary, but realistic approach, and that
all reasoning should be explicitly documented (IUCN, 2012b). For example, where a population
decline is known to have taken place (e.g. as a result of fisheries), but no management has been
applied to change the pressures on the population, it can be assumed the decline is likely to
continue in the future. If fisheries are known to be underway within the bathymetric range of a
species, but no information is available on changes in catch per unit effort (CPUE), data from
similar fisheries elsewhere may be used by informed specialists to extrapolate likely population
trends. In a few cases, modelled population data are available and inferred trends are sometimes
used where direct information is unavailable. Additionally, where no life history data are
available, the demographics of a very closely related species may be applied (Fowler and
Cavanagh, 2005). Finally, species designated as Not Evaluated were those whose extreme rarity in
Irish waters was not driven by their conservation status, but could be confidently attributed to the
species being classed as a rare vagrant, being on the edge of their distribution, or lacking sufficient
information on their distribution in Irish waters.
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Figure 1: Red List categories used for this assessment. Further details and definitions for these categories and
the criteria for achieving them are available in IUCN (2001, 2003) and are summarised in Appendix 1.
Geographic and Taxonomic scope
The geographic scope of this assessment covers the coastal, shelf and deep sea areas around
Ireland. The outer extent is the 200 mile Exclusive Economic Zone (EEZ) of the Republic of Ireland,
and the waters identified within The Adjacent Waters Boundaries (Northern Ireland) Order (S.I.
2002 No. 791)(Fig. 2). However, any species whose population straddles these boundaries and is
not considered a vagrant (Table 2) in Irish waters is included. The approach ignores geographic
structure within species, i.e. if several discrete populations occur in Irish waters, they are treated as
one.
The assessments cover Irish species of the class Chondrichthyes, the cartilaginous fish. The class is
divided into two subclasses: Elasmobranchii (sharks, rays and skates) and Holocephali (chimaeras,
sometimes called ghost sharks). The nomenclature and authorities used for fish in this review
follows Whitehead et al. (1984) and the World Register of Marine Species (WoRMS, 2016).
Not Evaluated (NE)
Near Threatened (NT)
Endangered (EN)
Critically Endangered (CR)
Vulnerable (VU)
Extinct in the Wild (EW)
Extinct (EX)
Least Concern (LC)
Data Deficient (DD)
Evaluated
Adequate
data
Regionally Extinct (RE)
Not Evaluated (NE)
Near Threatened (NT)Near Threatened (NT)
Endangered (EN)
Critically Endangered (CR)
Vulnerable (VU)
Endangered (EN)
Critically Endangered (CR)
Vulnerable (VU)
Extinct in the Wild (EW)Extinct in the Wild (EW)
Extinct (EX)Extinct (EX)
Least Concern (LC)
Data Deficient (DD)
Evaluated
Data Deficient (DD)Data Deficient (DD)
Evaluated
Adequate
data
Adequate
data
Regionally Extinct (RE)
8
Figure 2: The geographic scope of the Red List assessment includes the Exclusive Economic Zone of the
Republic of Ireland and the waters defined by the Northern Ireland Adjacent Waters Limit.
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Table 1: Checklist of cartilaginous fish species of Ireland after Whitehead et al. (1984) and WoRMS (2016), with current European (Nieto et al., 2015), Northeast Atlantic (Gibson et al.,
2008) and Global Red List (Camhi et al., 2009) designations.
Family (common)
Common name
Scientific name
NE Atlantic
Global
Europe
Cow sharks
Sharpnose sevengill shark
Heptranchias perlo
NT
NT
DD
Bluntnose sixgill shark
Hexanchus griseus
NT
NT
LC
Frilled sharks
Frilled shark
Chlamydoselachus anguineus
NT
NT
LC
Mackerel sharks
Porbeagle
Lamna nasus
CR
VU
CR
Shortfin mako shark
Isurus oxyrinchus
VU
VU
DD
Basking sharks
Basking shark
Cetorhinus maximus
EN
VU
EN
Common thresher shark
Alopias vulpinus
NT
VU
EN
Cat sharks
White ghost shark
Apristurus aphyodes
DD
DD
LC
Iceland catshark
Apristurus laurussonii
LC
DD
LC
Ghost shark
Apristurus manis
LC
LC
LC
Smalleye catshark
Apristurus microps
LC
LC
LC
Black roughscale catshark
Apristurus melanoasper
DD
DD
LC
Lesser-spotted dogfish
Scyliorhinus canicula
LC
LC
LC
Bull huss
Scyliorhinus stellaris
NT
NT
NT
Blackmouth dogfish
Galeus melastomus
LC
LC
LC
False cat sharks
Mouse catshark
Galeus murinus
LC
LC
LC
Requiem sharks
False catshark
Pseudotriakis microdon
DD
DD
DD
Hound sharks
Blue shark
Prionace glauca
NT
NT
NT
Tope
Galeorhinus galeus
DD
VU
VU
Rough sharks
Starry smooth hound
Mustelus asterias
LC
LC
NT
Gulper sharks
Leafscale gulper shark
Centrophorus squamosus
EN
VU
EN
Birdbeak dogfish
Deania calcea
VU
LC
EN
Kitefin sharks
Kitefin shark
Dalatias licha
VU
DD
EN
Bramble sharks
Bramble shark
Echinorhinus brucus
DD
DD
EN
Lantern sharks
Greater lantern shark
Etmopterus princeps
LC
DD
LC
Velvet belly lantern shark
Etmopterus spinax
NT
LC
NT
10
Black dogfish
Centroscyllium fabricii
LC
LC
LC
Sleeper sharks
Portuguese dogfish
Centroscymnus coelolepis
EN
NT
EN
Longnose velvet dogfish
Centroselachus crepidater
LC
LC
LC
Knifetooth dogfish
Scymnodon ringens
LC
DD
LC
Little sleeper shark
Somniosus rostratus
DD
DD
DD
Rough sharks
Sharp-back shark
Oxynotus paradoxus
DD
DD
DD
Dogfish sharks
Spurdog
Squalus acanthias
CR
VU
EN
Little gulper shark
Squalus uyato
DD
DD
VU
Angel shark
Squatina squatina
CR
CR
CR
Angel sharks
Electric ray
Tetronarce nobiliana
LC
DD
LC
Electric rays
Arctic skate
Amblyraja hyperborea
LC
LC
LC
Skates
Shorttail skate
Amblyraja jenseni
LC
LC
LC
Starry skate
Amblyraja radiata
LC
VU
LC
Pale skate
Bathyraja pallida
LC
LC
LC
Richardson's skate
Bathyraja richardsoni
LC
LC
LC
Blue skate
Dipturus flossada (= batis)
CR
CR
CR
Flapper skate
Dipturus intermedia (= batis)
CR
CR
CR
Norwegian skate
Dipturus nidarosiensis
NT
NT
NT
Longnosed skate
Dipturus oxyrinchus
NT
NT
NT
Sandy skate
Leucoraja circularis
VU
VU
EN
Shagreen skate
Leucoraja fullonica
NT
NT
VU
Cuckoo skate
Leucoraja naevus
LC
LC
LC
Krefft's skate
Malacoraja kreffti
LC
LC
LC
Blue skate
Neoraja caerulea
DD
DD
LC
Blonde skate
Raja brachyura
NT
NT
NT
Thornback skate
Raja clavata
NT
NT
NT
Small-eyed skate
Raja microocellata
NT
NT
NT
Spotted skate
Raja montagui
LC
LC
LC
Undulate skate
Raja undulata
EN
EN
NT
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Deep-water skate
Rajella bathyphila
LC
LC
LC
Bigelow's skate
Rajella bigelowi
LC
LC
LC
Round skate
Rajella fyllae
LC
LC
LC
Mid-Atlantic skate
Rajella kukujevi
DD
DD
LC
White skate
Rostroraja alba
CR
EN
CR
Common stingray
Dasyatis pastinaca
NT
DD
VU
Stingrays
Pelagic stingray
Pteroplatytrygon violacea
LC
LC
LC
Eagle rays
Eagle ray
Myliobatis aquila
DD
DD
VU
Devil ray
Mobula mobular
EN
EN
EN
Devil rays
Rabbitfish
Chimaera monstrosa
NT
NT
NT
Rabbitfish
Opal chimaera
Chimaera opalescens
LC
NE
LC
Small-eyed rabbitfish
Hydrolagus affinis
LC
LC
LC
Large-eyed rabbitfish
Hydrolagus mirabilis
LC
LC
LC
Pale ghost shark
Hydrolagus pallidus
LC
LC
LC
Longnose rabbitfish
Straightnose rabbitfish
Rhinochimaera atlantica
LC
LC
LC
Bentnose rabbitfish
Harriotta raleighana
LC
LC
LC
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Workshops and data collation
Assessments for the species were all carried out as part of a workshop with experts on the 23rd September
2014, with additional analyses of the data carried out in October 2014 December 2015. Workshop
participants who completed the assessments were Maurice Clarke (Marine Institute), Edward Farrell (Irish
Elasmobranch Group), Stephen Foster (Marine Division, DAERA Northern Ireland), Ferdia Marnell
(National Parks & Wildlife Service; NPWS), Tomás Murray (National Biodiversity Data Centre) and William
Roche (Inland Fisheries Ireland; IFI).
This Red List assessment was supported by the compilation of data for the Exclusive Economic Zone of the
Republic of Ireland and Northern Ireland Adjacent Waters Limit from national and international sources of
marine biodiversity data. In total, the dataset compiled by the National Biodiversity Data Centre represents
>57,000 records of 525,000 cartilaginous fish across 71 species from 1800-2014 (Fig. 3). Primary sources of
data included: the International Council for the Exploration of the Sea Database of Trawl Surveys and
associated Irish surveys conducted by the Marine Institute and the Department of Agriculture, Environment
and Rural Affairs N.I.; Inland Fisheries Ireland extensive tagging data and transitional water surveys; data
holdings within the National Biodiversity Data Centre and the Centre for Environmental Data and
Recording N.I.; the Irish Specimen Fish Committee; the Irish Basking Shark Study Group; the Irish Whale
and Dolphin Group and the Dublin Natural History Museum. Given the temporal distribution of the data
supporting the Red List (see Fig. 3) and the large proportion of quantitative data available in the last 10
years, data are presented across two time periods, <2005 and 2005-2014. This approach facilitates the
presentation of species’ distributions as well as future iterations of this Red List where change in status will
be assessed at decadal levels.
Figure 3. Number of records in the all-island database from 1800 to 1964, and for each decade thereafter to 2014.
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Aims
The Ireland Red List of cartilaginous fish aims to:
provide a full and objective assessment of extinction risk of sharks, rays, skates and chimeras from
Irish waters, using the IUCN categories and criteria (IUCN, 2001) and guidance on regional
assessments (IUCN, 2003)
allow for direct comparisons with the European and Global assessments
identify those species most in need of conservation interventions, with particular emphasis on issues
where Ireland can make an important contribution
identify the major threats to Ireland’s cartilaginous fish so that appropriate mitigating measures can
be identified and implemented.
Complete reassessment of this Red List is recommended in 2024
Table 2: Cartilaginous fish species excluded from the assessment and the rationale for exclusion.
Common name
Scientific name
Rationale for exclusion
Sharpnose sevengill shark
Heptranchias perlo
Few records, probably vagrant
Frilled shark
Chlamydoselachus anguineus
Few records, probably vagrant
Shortfin mako shark
Isurus oxyrinchus
Vagrant rarely recorded
Common thresher shark
Alopias vulpinus
Few records and at edge of distribution
False catshark
Pseudotriakis microdon
Few records and at edge of distribution
Bramble shark
Echinorhinus brucus
Few records, probably vagrant
Little sleeper shark
Somniosus rostratus
Few records, probably vagrant
Little gulper shark
Squalus uyato
One record and at edge of distribution
Arctic skate
Amblyraja hyperborea
Vagrant
Starry skate
Amblyraja radiata
Few records, probably vagrant
Pelagic stingray
Pteroplatytrygon violacea
Vagrant
Eagle ray
Myliobatis aquila
Few records and at edge of distribution
Devil ray
Mobula mobular
Few records and at edge of distribution
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SUMMARY OF FINDINGS
The Red List assessment found that of the 58 species evaluated, 6 were Critically Endangered: Portuguese
dogfish (Centroscymnus coelolepis); common (blue) skate (Dipturus batis (= flossada)); flapper skate (Dipturus
intermedia); porbeagle shark (Lamna nasus); white skate (Rostroraja alba) and angel shark (Squatina squatina).
A further 5 species were assessed as Endangered: leafscale gulper shark (Centrophorus squamosus); basking
shark (Cetorhinus maximus); common stingray (Dasyatis pastinaca); undulate skate (Raja undulata) and
spurdog (Squalus acanthias).
An additional 6 species were assessed to be Vulnerable: longnose velvet dogfish (Centroselachus crepidater);
kitefin shark (Dalatias licha); tope (Galeorhinus galeus); shagreen ray (Leucoraja fullonica); longnose skate
(Dipturus oxyrinchus) and cuckoo ray (Leucoraja naevus).
Of the remaining species, 19 were assessed as Near Threatened and 22 species as Least Concern. No species
were considered to be data deficient (Appendix 2; Figure 3).
During the data compilation process, more than 520,000 records of cartilagenous fish across 71 species were
collated spanning the period from 1800-2014.
Figure 4: The number of species in each of the IUCN categories following the assessment.
The classification of the Portuguese dogfish, common (blue) skate, flapper skate, porbeagle shark, white
skate and angel shark as Critically Endangered reflects the decline of these species throughout the north east
Atlantic. The species in this category are mostly widely distributed or highly migratory. Their conservation
must be on an international scale, however the particular importance of Irish waters be taken into account.
These species currently receive a high level of protection under the EU Common Fisheries Policy, though
this is not an effective measure in every case. For Portuguese dogfish, the main international threat (deep-sea
fishing) occurs in Irish waters and their immediate vicinity. It is currently subject to a total allowable catch of
zero, but this is ineffective because it is a discarded by-catch in international fisheries for deep water fish.
15
Porbeagle shark, though no longer targeted, is vulnerable as by-catch in some commercial fisheries across
the eastern north Atlantic, but Irish waters are an important hotspot for the species. The three skate species
and angel shark have known refuges in Irish waters, and Ireland is well placed to augment existing
international conservation efforts. Indeed the Irish area is the last known refuge of the white skate in NW
Europe, and one of the few known refuges for angel shark. These species, apart from Portuguese dogfish, are
on the European Union’s Common Fisheries Policy (CFP) Prohibited Species List, but as they are still taken
as incidental by-catch, this measure is not very effective.
The Endangered classification was assigned to leafscale gulper shark, basking shark, common stingray,
spurdog and undulate skate. The leafscale gulper shark, like Portuguese dogfish, is mainly threatened in and
around Irish waters. Unlike that species, however, only a part of its life history is vulnerable in Irish waters.
Undulate skate and common stingray are widely distributed, and endemic in the NE Atlantic, but have
discrete and localised populations off southwest Ireland, both centered on Tralee Bay.
Conservation/management actions for these two species will necessarily have a spatial dimension, with
Ireland being well placed to make a significant contribution. Spurdog is a widely distributed species, but is
vulnerable as by-catch in mixed bottom fisheries in Irish waters. However, all target fisheries have ceased.
All target fisheries for basking shark are now banned, and the main threat is incidental by-catch or collisions
with ships or fishing gear. Basking shark is on the CFP Prohibited Species List. The spurdog, undulate skate
and leafscale gulper shark total allowable catch quotas (TAC) are currently set at zero. This measure is most
effective for spurdog, though some unavoidable by-catch occurs in demersal fisheries. For leafscale gulper
shark, the 0 tonnes TAC is not effective, due to continued by-catch. There is no management or conservation
measure in place for common stingray.
Of the species in the Vulnerable category, two (longnose velvet dogfish and kitefin shark) are deep-sea
species, one (tope) is a widely distributed migratory shark, shagreen and cuckoo ray are offshore shelf
species, whilst longnose skate inhabits both shelf and deepsea habitats. The longnose velvet dogfish shares
the vulnerability and susceptibility of Portuguese dogfish. The kitefin shark is equally vulnerable but less
susceptible, as its main distribution is around the Azores. The two rays in this category are taken in
international mixed demersal fisheries on the mid and outer shelf. Both are managed by the CFP as
commercial species, though the mixed-species total allowable catch (TAC) is not a very efficient means to
achieve sustainable harvesting. The longnose skate may be mis-classified in this category, and might be up-
listed in the future, if better information becomes available. Currently it is rarely encountered, is vulnerable
on account of its biology, and is susceptible to many fisheries but is not covered by any management or
conservation legislation. Kitefin shark is on the CFP Prohibited Species List in its core distribution area, the
Azores.
Comparison with other Red Lists
For the species evaluated in the Irish Red List, a comparison with the Global and Northeast Atlantic and
European lists is provided in Table 3. Overall the numbers of species in each category were broadly
comparable, though the Irish list process avoided using the Data Deficient category. The number of species
in the three threatened categories was progressively higher moving from the global to the national level.
16
Table 3: Comparison of Irish, Northeast Atlantic and Global Red List designations for cartilaginous fish on the Irish
species list. (Due to rounding not all columns may add to 100).
Category
Irish (%)
Europe (%)
Northeast Atlantic (%)
Global (%)
Critically Endangered
10
8
8
3
Endangered
9
14
10
6
Vulnerable
10
7
5
11
Near Threatened
32
15
23
18
Least Concern
38
49
50
47
Data Deficient
0
7
5
15
Threats to cartilaginous fish in Irish waters
The foremost risk in Irish waters is over-exploitation in commercial fisheries. This may be targeted fishing in
the past as was the case for spurdog and porbeagle sharks, or as unintended by-catch in fisheries for other
species, as is the case for the large bodied skates. At present there is no target fishery for any threatened
species. However several of these continue to be taken as by-catch in other fisheries.
Fisheries in Irish waters can be divided into three main categories; pelagic (or mid water), demersal (or
benthic) and deep-water (below 400-600 m depth). A large proportion of European fishing effort focuses on
Irish waters, and on fish stocks in, or straddling, Irish waters.
Pelagic fisheries mainly target mackerel, herring, horse mackerel, blue whiting, sprat, tunas and boarfish.
Fisheries for small pelagic species are almost exclusively by mid-water trawl. The main species which are
vulnerable to such fishing are pelagic sharks and dogfishes, though by-catch is infrequent. Fisheries for large
pelagic species (e.g. tunas) are either by mid-water trawl or by hook and line. Pelagic longline fishing results
in a considerable by-catch of pelagic sharks. The countries involved in pelagic fishing are Ireland, UK,
Norway, the Netherlands, France, Germany and Denmark. The Faroe Islands and Russia are also active,
adjacent to but not in Irish waters. Albacore tuna fishing is conducted in Irish waters by Irish, UK, French
and Spanish boats. Japan and other Pacific nations’ vessels were previously active in targeting bluefin tunas
beyond Irish territorial limits.
Demersal fishing mainly uses trawled gears in Irish waters, targeting a variety of species, such as gadoids,
plaice/sole, hake, monkfish and/or megrims, separately but usually in a mix. The countries involved are
France, UK, Ireland, Spain and Belgium. Demersal and shelf dwelling sharks, rays and dogfishes are all
taken in these fisheries. There are also a few target fisheries for rays using trawl (Irish Sea, Donegal Bay), and
using gillnets or other artisanal methods in coastal areas. Discarding is a feature of demersal fisheries in
general. Discard survival would only be high if trawl towing time is short, and compression in the trawl cod
end, due to weight of bulk catch, is limited. Gill net and longline fisheries, usually targeting hake, ling,
pollack or monkfish are operated by vessels from Spain, France, UK and Ireland and elasmobranch by-catch
is a feature of these fisheries also.
Deep-sea fishing takes place on the continental slopes, mainly off Donegal and northwards into the Scottish
sector, and also around Rockall. The main fleet involved is French bottom trawlers, which target mixed
teleosts with an unavoidable by-catch of deepwater sharks and rays.
17
Recreational angling is a potential threat to cartilaginous fish. However, in Irish waters, angling for these
species is almost exclusively on a catch-and-release basis. This lessens the risk considerably, but it would be
desirable to develop a national catch and release code of practice to ensure that threatened species are
handled correctly by anglers before being returned alive to the water. Over the past decade anglers have
become more cognisant of conservation requirements and the benefits of good handling. Many of the
threatened species are tagged by charter boat angling skippers as part of a long-running Inland Fisheries
Ireland tagging programme. In Northern Ireland tags issued under licence by the Department of
Agriculture, Environment and Rural Affairs for tagging and releasing Common Skate (Flapper and Blue
Skates) are also being applied to Porbeagle Shark.
Ship strikes and collisions with recreational craft are potential risks, though perhaps only of relevance to
basking shark. Mitigation measures should include a code of conduct and educational programmes targeted
at areas of high risk. Other threats that may become relevant in the future include habitat loss and pollution,
but to date these are not considered to be of any significance in Ireland.
Management and conservation actions
The main body of measures for the management and conservation of cartilaginous fish in Irish waters is the
European Union (EU) Common Fisheries Policy (CFP) framework. There are two main elements to this, the
prohibited species list, and the catch quota system.
Species on the Prohibited Species List must not be fished, retained on board, transhipped or landed. The list
appears in the annual EU Council Regulation covering fisheries management including quotas. Though the
list is subject to annual review by the Council of the EU, it is essentially a long term strategy to prevent any
fishing for species that are in need of conservation action.
The catch quota, or total allowable catch (TAC) system covers species that are managed to ensure maximum
sustainable yield in commercial fisheries. Apart from several commercial ray species, no cartilaginous fish
currently has an allowable catch level, because they cannot provide maximum sustainable yield (MSY).
Managing stocks to MSY underpins the Common Fisheries Policy. Catch quotas are agreed by the EU
Council annually for shelf species and biennially for deep-sea species.
There are several technical regulations in EU fisheries legislation. They are not designed to limit mortality,
but to achieve other aims such as improved selectivity or elimination of undesired practices. Since 1997 it has
been forbidden to target pelagic sharks, billfish or tunas with pelagic gillnets. This was in response to
concerns of cetacean by-catch (EC Regulations 894/97 and 809/2007). There has been a general ban on
removal of fins from sharks in European fisheries, since 2003 (EC 605/2013 and 1185/2003). This was in
response to public concern about the practice of shark finning. There is a ban on gillnetting in depths deeper
than 600 m in EU waters (EC Regulation 41/2007), and deeper than 200m in international waters (Northeast
Atlantic Fisheries Commission). These measures were brought in to regulate ghost fishing (Hareide et al.
2005). The minimum trawl cod-end mesh size that can be used in demersal target fisheries for rays is 100mm,
though meshes of 80mm are permitted if there is a by-catch of other species (EC Regulation 850/98). This
measure is aimed at achieving improved selectivity of teleost species rather than for rays.
The Convention on Migratory Species (CMS or Bonn Convention) promotes international cooperation for
migratory species. Species threatened with extinction are listed on CMS Appendix I. Parties that are range
18
states to Appendix I species are obliged to afford them strict protection through additional measures.
Migratory species that need or would significantly benefit from international co-operation are listed in
Appendix II of the Convention. CMS encourages, inter alia, the establishment of regional or global MoUs to
promote cross-border conservation efforts. The Republic of Ireland, Northern Ireland (UK) and the European
Union are all signatories to CMS.
CITES (the Convention on International Trade in Endangered Species of Wild Fauna and Flora) is a
multilateral treaty to regulate trade in plants and animals endangered with extinction. Appendix I covers
species threatened with extinction that are affected by trade. Commercial trade in Appendix I species is
illegal. Appendix II covers species that are not necessarily threatened with extinction, but may become so
unless trade is regulated. International trade in specimens of Appendix II species may only take place by the
granting of an export permit or re-export certificate, and requires proof that this would not be detrimental to
the species. The Republic of Ireland, Northern Ireland (UK) and the European Union are signatories.
The Wildlife (Northern Ireland) Order 1985 (as amended in 2011) offers protection for common skate, angel
shark and basking shark out to 6 nautical miles from baseline. There is no other domestic legislation
covering any cartilaginous fish in Irish waters, north or south. Table 4 shows the relevant legal instruments
and other international agreements in place for all cartilaginous fish species in Irish waters.
The Convention for the Protection of the Marine Environment of the North-East Atlantic (OSPAR) seeks to
identify species in its area that are being threatened and/or declining and are in need of protection. OSPAR
lists such species, upon recommendation by contracting parties or observers. This list is not binding, but is
intended to be used as a basis for future management/conservation action. OSPAR shares many of the
species with other lists, but also considers thornback and spotted rays which are not of high conservation
concern.
The Marine Strategy Framework Directive (MSFD), of the EU, aims to achieve Good Environmental Status
(GES) of the EU's marine waters by 2020. It is the first EU legislative instrument related to the protection of
marine biodiversity, as it contains the explicit regulatory objective that "biodiversity is maintained by 2020",
as the cornerstone for achieving GES. The Directive enshrines in a legislative framework the ecosystem
approach to the management of human activities having an impact on the marine environment, integrating
the concepts of environmental protection and sustainable use. In order to achieve GES by 2020, each
Member State is required to develop a strategy for its marine waters (or Marine Strategy). In addition,
because the Directive follows an adaptive management approach, the Marine Strategies must be kept up-to-
date and reviewed every 6 years. Though in its initial stages, the MSFD will provide a legal framework by
which commercially exploited chondrichthyan fish must be maintained within safe biological limits,
exhibiting a population age and size distribution that is indicative of a healthy stock”. The MSFD also has a
biodiversity requirement that the distribution and abundance of species are in line with prevailing
physiographic, geographic and climate conditions”.
Under the EU Water Framework Directive (WFD), River Basin Management Plans (RBMP) address the
ecological and chemical status objectives of coastal water bodies (defined as marine waters extending to ≤
1km from baseline). Where required, programmes of measures will be implemented to ensure the water
body meets WFD targets of Good Ecological Status (GES) by 2027. In coastal water bodies, under the WFD,
GES refers to a defined biological objective based on physico-chemical and hydromorphological parameters.
Fish community monitoring is required only for transitional waters, potentially valuable breeding and
19
nursery areas for some species, and includes assessments of species composition and abundance in addition
to providing data on the presence of sensitive species.
The International Plan of Action for Conservation and Management of Sharks (IPOA-SHARKS) was
developed through the United Nations Food and Agricultural Organisation (UN FAO) in 1998. It is a
voluntary framework to achieve the conservation and management of cartilaginous fishes and their long-
term sustainable use. The EU, through the European Commission, produced a framework IPOA in 2009.
This encompasses existing EU fisheries legislation and envisages further measures in the future. EU Member
States may also develop national IPOAs. These can include stronger measures than the EU framework.
There are no measures in Ireland to regulate ship strikes or harm by recreational vessels to surface
swimming sharks. However the legal mechanism exists for countries to develop such measures, under the
UN International Maritime Organisation (IMO), and examples exist elsewhere in the world for the
protection of whales.
In Northern Ireland it is illegal to deliberately fish for common skate (flapper skate and blue skate) within 6
nautical miles of baseline. A small number of anglers have been issued with licences to tag and release skate
for scientific purposes. Otherwise there is no domestic or EU legislation covering recreational angling for
any cartilaginous species. However voluntary catch and release or tag and release codes of practice usually
apply.
Cartilaginous Fish Red List 2016
20
Table 4. Management and conservation measures in place for cartilaginous species in Irish waters, showing also the Red List designations.
Common name
Scientific name
Irish 2016
Europe
2015
NEA 2008
Global
CFP
Prohibited
Species
2015
CFP
allowable
catch
OSPAR List
NI Wildlife
Order
CITES
CMS
2009
Angel shark
Squatina squatina
CR
CR
CR
CR
Yes
Yes
Yes
Common (blue) skate
Dipturus batis (= flossada)
CR
CR
CR
EN
Yes
Yes
Flapper skate
Dipturus intermedia
CR
CR
CR
CR
Yes
Yes
Porbeagle
Lamna nasus
CR
CR
CR
VU
Yes
Yes
II
II
Portuguese Dogfish
Centroscymnus coelolepis
CR
EN
EN
NT
No
Yes
White Skate
Rostroraja alba
CR
CR
CR
EN
Yes
Yes
Basking shark
Cetorhinus maximus
EN
EN
EN
VU
Yes
Yes
Yes
II
I, II
Leafscale gulper shark
Centrophorus squamosus
EN
EN
EN
VU
No
Yes
Spurdog
Squalus acanthias
EN
EN
EN
VU
No
Yes
II
Undulate Skate
Raja undulata
EN
NT
NT
EN
No
Cuckoo ray
Leucoraja naevus
VU
LC
LC
LC
Yes
Kitefin shark
Dalatias licha
VU
EN
EN
NT
No
Shagreen Ray
Leucoraja fullonica
VU
VU
VU
VU
Yes
Tope
Galeorhinus galeus
VU
VU
VU
VU
longline
only
Birdbeak dogfish
Deania calcea
NT
EN
NT
LC
No
Blonde ray
Raja brachyura
NT
NT
NT
NT
Yes
Bluntnose sixgill shark
Hexanchus griseus
NT
LC
NT
NT
No
Greater lantern shark
Etmopterus princeps
NT
LC
LC
DD
No
Knifetooth dogfish
Scymnodon ringens
NT
LC
LC
DD
No
Norwegian skate
Dipturus nidarosiensis
NT
NT
NT
NT
Yes
Sandy Ray
Leucoraja circularis
NT
EN
EN
EN
Yes
Cartilaginous Fish Red List 2016
21
Sharp-back Shark
Oxynotus paradoxus
NT
DD
DD
DD
No
Black dogfish
Centroscyllium fabricii
LC
LC
LC
LC
No
Mouse catshark
Galeus murinus
LC
LC
LC
LC
No
Small-eyed ray
Raja microocellata
LC
NT
NT
LC
No
Spotted Ray
Raja montagui
LC
LC
LC
LC
Yes
Thornback ray
Raja clavata
LC
NT
NT
NT
Yes
Yes
Velvet Belly Lantern Shark
Etmopterus spinax
LC
NT
NT
LC
No
Bigeye thresher shark
Alopias superciliosus
NE
EN
NT
VU
II
Common thresher shark
Alopias vulpinus
NE
EN
NT
VU
II
Frilled shark
Chlamydoselachus anguineus
NE
LC
NT
No
Gulper shark
Centrophorus granulosus
NE
CR
CR
VU
No
Yes
Shortfin Mako
Isurus oxyrinchus
NE
DD
VU
II
Cartilaginous Fish Red List 2016
22
Current and future research priorities
While a Red List will identify the species most at risk of extinction within a geographical area, taking that
further to categorize national conservation priorities will require further steps i.e. building upon the Red List
but including other biological, financial, political and cultural factors to prioritise effort across species
(Fitzpatrick et al., 2007).
Research should ideally focus on the threatened, and the “Near Threatened” species, which can be separated
into three groups:
The group of highest research priority consists of those species forming endemic or apparently endemic
populations in Irish waters, namely: the angel shark, undulate skate, common stingray, white, blue, flapper
and longnose skates and the sandy ray. Future work should focus on establishing population size, trends
over time, connectivity with other populations and identification of critical habitats and locations for
important life history stages, such as spawning and nursery areas. Population size estimates could variously
be based on mark and recapture studies (e.g. Inland Fisheries Ireland tagging data), molecular genetics
approaches (effective population size estimators) or a combination of both. The management of certain areas
should be supported by a specific research and monitoring programme which would be linked to clear
conservation and biodiversity objectives with appropriate performance indicators. Tralee Bay, where several
of the threatened and near threatened species (e.g. angel shark, undulate skate, stingray and larger skates)
occur, is an ideal candidate. Findings and outputs from a time-bound research programme there would also
serve to inform future conservation management policy for Irish waters more generally.
An extension of citizen science programmes such as the Purse Search initiative would be a cost effective
means to identify spawning and nursery areas for the skates and rays. Enhancing engagement with the
recreational angling sector to facilitate improved reporting of ‘rare’ or threatened elasmobranch species is
another example of a low cost citizen science programme. For both, the development and use of specific
mobile phone apps would provide an informal but valuable reporting mechnism and increased public
awareness of the issue of species conservation. The focus of the suite of activities above should be within
Ireland, however, wider collaboration should take place to evaluate the importance of Irish refuges in the
international context.
The second highest research priority belongs to species currently taken in commercial fisheries, where
allowable catch is permitted, but which are in decline or over-fished; the cuckoo, shagreen and blonde rays
and tope. Current scientific data are patchy for these species. Further work is required to identify the
population size, trends over time, movements, migrations, critical habitats, spawning and nursery areas. The
level of by-catch and discarding from commercial fisheries needs to be quantified, as does the rate of discard
survival under normal fishing conditions. New demographic studies and stock assessments are required and
should be used to identify sustainable fishing levels, and, where relevant suitable management measures,
including technical measures.
The third level of priority is assigned to widely distributed and/or highly migratory species for which
Ireland is an important part of a wider distribution, but for which Ireland can only contribute to a wider
international effort. To this category belong most of the deep-sea species, porbeagle, blue shark, basking
shark and spurdog. Some of these species are already receiving attention from the international scientific
community, but these efforts must be intensified. Spurdog has a well developed population assessment
model in place, and future work should focus on using this model to develop a rebuilding plan, with stock
size targets, timelines and actions to achieve them. The situation for the deep-sea sharks is similar and the
Cartilaginous Fish Red List 2016
23
international focus should be on incorporating existing knowledge into a rebuilding plan for the species
assemblage as a whole. For blue shark, international efforts to achieve a population assessment through the
International Convention for the Conservation of Atlantic Tunas (ICCAT) should continue, particularly to
quantify total catch in the main fisheries by Japan, Spain and the USA. Tagging and other work on porbeagle
and basking shark should continue and focus on identification of spawning, nurseries and other important
areas. The most poorly understood component of this group are the deep-sea rays. Some work has been
done on mapping their distributions, but additional studies are required together with fundamental work on
their life histories where information is totally lacking.
SPECIES ACCOUNTS
A brief explanation of the headings in the species accounts is provided below:
Species name and taxonomic authority
Common name - English language name
Irish name - common name as Gaeilge
Status Red list status for Ireland (identified during this assessment and using the IUCN categories
and criteria (IUCN, 2001; 2012a)); red list status for the North-east Atlantic if available, (see Nieto et
al., 2015) and the Global red list status taken from IUCN Red List of Threatened Species (IUCN,
2010)
Rationale for assessment a description of how the IUCN category was determined for Ireland.
This will include information on any available population trend data. This section should be read in
conjunction with the IUCN guidance documents that were used for this assessment (IUCN, 2001;
2003; 2012b).
Range, Distribution and Habitat a general description of the NEA distribution of the species,
followed by a more detailed description of its distribution and habitat usage in Irish waters.
Biology / Ecology a brief overview, where known, of the species reproductive biology, life history
and feeding ecology.
Human Impacts a brief outline of any significant activities impacting on the species conservation
status in Ireland.
Management/conservation Any legal or international protection, management or conservation
measures afforded the species.
Cartilaginous Fish Red List 2016
24
OCEANIC AND PELAGIC SPECIES
Lamna nasus (Bonneterre, 1788)
Porbeagle
Irish name: Craosaire
Status
Ireland: Critically Endangered A2 bd. NE Atlantic: Critically Endangered. Global: Vulnerable.
Justification
Porbeagles (Lamna nasus) are highly vulnerable to fishing mortality and very slow to recover from depletion
due to their slow growth rate, low fecundity and late age at maturity. Northeast Atlantic porbeagles have
been heavily exploited by commercial longline fisheries since the early 1900s for their high value meat. They
have undergone significant declines in abundance due to this exploitation: over 90% decline from baseline in
the northeast Atlantic and as such are listed as Critically Endangered.
Range, distribution and habitat
The porbeagle is a large pelagic, migratory, coastal and oceanic species found in temperate and cold-
temperate waters worldwide. In the Northeast Atlantic porbeagles occupy a broad distributional range from
the Barents Sea to northwest Africa. The Northeast Atlantic population is considered to be a single stock and
is managed as such. There are also populations of porbeagles in the northwest Atlantic and in the south
Atlantic.
It has long been considered that the north Atlantic populations comprised two distinct stocks of porbeagles:
northeast and northwest (Campana et al., 1999). This hypothesis is largely based on a relatively small
number of conventional tag returns from Norwegian, US and Canadian tagging programmes. However a
transatlantic migration has been reported (Green, 2007) and more recently a porbeagle tagged with a pop-up
archival transmission tag off Ireland crossed over half of the North Atlantic before the tag was released
(Bendall et al., 2012). Furthermore, a recent study has confirmed that some gene flow occurs across the North
Atlantic (Pade, 2009).
Porbeagles are found on all coasts of Ireland but are more common north of Lough Swilly in Donegal and
also off the coasts of Galway, Clare and Cork. The Irish record rod caught porbeagle weighing 365lb was
taken in 1932 in Keem Bay, Achill Island.
Cartilaginous Fish Red List 2016
25
Biology and Ecology
The biology of porbeagles is well described for the Northwest Atlantic stock (Natanson et al., 2002), where
the age-at-maturity is estimated at 8 and 13 years for males and females, respectively. Less information is
available for the Northeast Atlantic stock, though it is estimated that males and females do not mature until
they are 1.7 and 2.0m fork length, respectively (Hennache & Jung, 2010). These lengths correspond to an
estimated age-at-maturity of 7-8 years for males and approximately 20 years for females, showing them to be
slow growing and late maturing. In Irish waters the majority of rod caught porbeagles are < 2.0m total length
and the sex ratio is 1:1 (IFI, unpublished).
Porbeagles favour waters between 5-20°C and are among the small number of sharks that can actually
maintain a higher body temperature than the water around them. They are recorded in Irish waters between
June and October (angling data), where they feed mainly on boney fish such as pollock, whiting, blue
whiting, mackerel and also herring.
Trend
Porbeagles have undergone significant declines in abundance due to commercial exploitation: over 90%
decline from baseline in the Northeast Atlantic and over 80% decline from baseline in the northwest Atlantic
Cartilaginous Fish Red List 2016
26
(ICCAT/ICES, 2009). This is confirmed by unpublished tagging data from Inland Fisheries Ireland which
also imply a very modest increase in CPUE in recent years.
Human impacts
Porbeagles were common in the northeast Atlantic and because of this they were fished commercially for
most of the 19th and 20th centuries. The main countries involved were Norway, Denmark, Spain and France.
Landings of porbeagles peaked in the period of 1933-1939 when 2,000 to 4,000 tonnes were landed by
Norway annually. The porbeagle fishery subsequently declined but continued in various countries until
2010 when targeted fishing for porbeagle in EU waters became illegal. The species continues to be a by-catch
in some fisheries, including the international blue whiting trawl fishery, and some bottom trawl fisheries.
Management/Conservation
This species is on the EU CFP Prohibited Species List, and was previously regulated by a TAC, which since
2010 was set at zero TAC. It is subject to a management plan in Canadian waters where it is targeted
commercially. In 2012 the North East Atlantic Fisheries Commission (NEAFC) prohibited all directed fishing
in international waters. In March 2013 porbeagle was listed on Appendix II of CITES. It is also listed on
Appendix II of the Convention on Migratory Species from 2008.
Cetorhinus maximus (Gunnerus, 1765)
Basking Shark
Irish name: Liamhán gréine
Status
Ireland: Endangered A1abd. NE Atlantic: Endangered A2abd. Global: Vulnerable A2ad+3d.
Justification
Basking sharks (Cetorhinus maximus) have a long history of exploitation, particularly in the Northeast
Atlantic. Annual catches by former directed fisheries in Norway, Ireland and Scotland fell by approximately
90% during a period approximating half a generation. The species is susceptible to exploitation due to its
large size and aggregating behaviour. Although the fishery has ceased, population recovery in basking
sharks can be very slow due to low productivity and late age at maturity. For these reasons basking shark is
assessed as “Endangered”.
Range, distribution and habitat
The basking shark is a very large, filter-feeding species that is migratory and widely distributed, but only
regularly seen in a few coastal locations and probably never abundant. In the eastern Atlantic, basking
sharks are distributed from Iceland, Norway and as far north as the Russian White Sea (southern Barents
Sea), south to the Mediterranean and occasionally as far south as Senegal (Compagno, 1984; Konstantinov
and Nizovtsev, 1980). A single population is believed to exist in the Northeast Atlantic although there is one
report of an east-west trans-Atlantic migration (Gore et al., 2008). Trans-equatorial migrations and
migrations into tropical areas and mesopelagic depths are also reported in the North Atlantic, including
autumn southward movements to areas off North Africa (Madeira) for overwintering (Witt et al., 2013).
Migration and levels of mixing between populations have yet to be fully determined. An active research and
conservation interest in this species in recent years has led to an increase in the number of sightings reported
Cartilaginous Fish Red List 2016
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around Ireland. In Irish waters basking sharks are most commonly observed off the coasts of Donegal, Mayo,
Cork and Kerry.
Biology and Ecology
Little is known about the biology of this species. The reproductive biology is considered to be similar to that
of other lamnoid sharks (Kunzlik 1988). Pairing takes place in early summer following courtship behaviour
(Sims et al., 2000b), with wounds caused by copulation having been recorded in British waters in May by
Matthews (1950). A single functional ovary contains a very large number of small eggs. Estimates for
gestation period range from 12-36 months (Parker and Stott 1965, Pauly 1978, 2002, Compagno 1984a). The
smallest free-swimming individuals recorded are about 1.7-1.8m (Parker and Stott 1965; Sims et al. 1997).
However, the young are very rarely encountered until they reach more than 3 m in length. Males become
sexually mature at a length of 5-7m and females at 8.1-9.8m (Compagno 1984a).
Basking sharks are plankton feeders and are often associated with high levels of chlorophyll and surface
aggregations of zooplankton, particularly along tidal and shelf-break fronts. They are most often observed
when feeding in surface waters by swimming open-mouthed and continuously filtering the water.
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Trend
A decline is inferred from landing records over time. The target fishery ceased even though markets still
existed for the species. This implies that the population did not recover, and is assumed to have stabilised at
a low level (ICES, 2005).
Human impacts
In Irish waters there were three main fisheries for basking waters; the 18th to 19th Century Sunfish Bank
fishery, the mid-20th Century Achill Island fishery, and the modern Norwegian fishery (ICES, 2006;
McNally, 1976; Parker and Stott, 1965). Records suggest that the initial fishery was active for several decades
between 1770 and 1830, with at least 1,000 sharks caught per year. In the early 1830s, sharks became very
scarce and the fishery collapsed in the second half of the 19th Century. This scarcity of sharks lasted for
several decades. In the middle of the 20th Century a new fishery began at Achill Island, where between 1,000
and 1,800 sharks were taken each year from 1951 to 1955. Thereafter annual catches dropped to around 480
in 1956 -1960, around 100 in 1961-65, and then about 50-60 for the remaining years of the fishery. Basking
shark was also targeted by Norwegian harpoon vessels in the Celtic Seas until comparatively recently. Today
the species is an occasional by-catch in demersal trawl fisheries and entanglement in static fishing gear. They
are also susceptible to collisions with vessels.
Management/Conservation
This species is on the EU CFP Prohibited Species List. It is also protected in Northern Ireland, (since 2011)
and on the high seas of the Northeast Atlantic and the Mediterranean (2012, through NEAFC). It is listed on
Appendices I and II of the Convention on Migratory Species, and on Appendix II of CITES.
Galeorhinus galeus (Linnaeus, 1758)
Tope
Irish name: Gearrthóir
Status
Ireland: Vulnerable A2 bd. NE Atlantic: Vulnerable A2bd. Global: Vulnerable A2bd+3d+4bd
Justification
Data on tope (Galeorhinus galeus) are limited, as landings are often included as "dogfishes and hounds". An
exploratory assessment of CPUE trends from over 20 years of trawl survey data from the Northeast Atlantic
suggests a decline in abundance (Dureuil 2013). Given the low productivity and recovery rate of this species,
it is classified as “Vulnerable” and should be monitored closely.
Range, distribution and habitat
Tope is widespread in the eastern Atlantic, ranging from Iceland and Norway to South Africa, including the
Mediterranean Sea. It also occurs off Australia and New Zealand, the southwest Atlantic (Brazil to
Argentina) and the eastern Pacific (Compagno, 1984). There is believed to be a single stock of Tope in the
northeast Atlantic region (ICES 2012). This is supported by tagging work conducted by Inland Fisheries
Ireland showing wide migrations between the North Sea, west of Scotland and Ireland as far south as the
Canary Islands, the Azores, northwest Africa and the western Mediterranean (Fitzmaurice et al. 2003e). It is
suggested that the northeast Atlantic and Mediterranean stock of tope is isolated from other stocks around
the world, with little to no gene flow between them (Chabot and Allen 2009).
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Biology and Ecology
Life-history data for tope in the Northeast Atlantic are limited. The maximum reported length in the
northeast Atlantic area was 169cm TL for a female in the North Sea (McCully et al., 2013). The length at
maturity of this species in the Northeast Atlantic was suggested, based on modelled data, to be 155 cm for
females and 121cm for males (Dureuil 2013), based on data from the Azores, Madeira (Couto 2013) and the
Mediterranean Sea (Capape and Mellinger 1988, Capape et al. 2005). On this basis the age at 50% maturity
was estimated as 21 years for females and 12 years for males. Longevity of tope in the Northeast Atlantic
was estimated to be 55 years (Dureuil 2013). In Ireland tags have been returned from tope at liberty for
almost 20 years (IFI, unpublished), while this has extended to 35 years in Australia (Moulton et al., 1989).
Trend
An exploratory assessment of CPUE trends from over 20 years of trawl survey data from the Northeast
Atlantic suggests a decline in abundance (Dureuil 2013).
Human impacts
There are no targeted commercial fisheries, but it is taken as by-catch in trawl, gillnet and longline fisheries,
including demersal and pelagic set gears, though it is sometimes discarded. It was a by-catch in the now
defunct drift net fisheries for salmon around the Irish coast. Tope is also an important target species in
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recreational sea angling in several areas, with anglers and angling clubs following catch and release
protocols and many of these fish are subsequently tagged.
Management/Conservation
In the UK fishing for tope other than by rod and line (with anglers fishing using rod and line from boats not
allowed to land their catch) is prohibited and there is a bycatch limit of 45 kilograms per day for commercial
fisheries targeting other species (ICES 2012). Tope is on the CFP Prohibited Species List, but for longline
fishing only.
Prionace glauca (Linnaeus, 1758)
Blue Shark
Irish name: Siorc gorm
Status
Ireland: Near Threatened. NE Atlantic: Near Threatened. Global: Near Threatened.
Justification
Given the current state of knowledge it is difficult to determine the status of blue shark (Prionace glauca)
stocks with a high degree of confidence, but on the basis of high catch rates, high consumer demand and at
present a conflicting picture of population trends, it is evaluated as Near Threatened.
Range, distribution and habitat
The blue shark has a circumglobal distribution and is common in pelagic oceanic waters throughout the
tropical and temperate oceans worldwide. It has one of the widest ranges of all the shark species. It is
oceanic and pelagic, found from the surface to about 350m depth. There is considered to be one stock of blue
shark in the North Atlantic (ICES, 2013) and this is supported by extensive tagging studies in Ireland
(Fitzmaurice et al., 2003b) and the USA (Kohler et al., 1998).
In the North Atlantic blue sharks migrate northward during the summer and so occur primarily between
June and September in Irish waters. Their arrival in Irish waters is often associated with sea surface
temperature reaching 15°C. They are most abundant off the south west and west coast and are targeted
mainly by charter angling vessels (Fitzmaurice et al., 2003b).
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Biology and Ecology
The Blue Shark reaches a maximum length of about 380cm TL. About 50% of males in the Atlantic are
sexually mature by 218cm, although some may reach maturity as small as 182cm. Females are sub-adult
from 173-221cm and fully mature from 221cm (Pratt, 1979). The length-at-birth is 30-50cm and the average
fecundity is 25-50 pups (ICES, 2013). Life-history information from blue sharks caught in Irish waters is
limited. The age range of samples caught in Irish waters indicates that the population occurring north of
Biscay is composed mainly of sub-7-year-olds (Henderson et al., 2001). In Irish coastal waters the sex ratio is
skewed towards females (Fitzmaurice et al., 2003b), but further offshore it is more balanced (MacNaughton et
al., 1998).
Trend
Conflicting signals are available from various sources. Catch rates from Irish recreational catches showed a
decline over time (Fitzmaurice et al., 2005), and have stabilised at this level in the past decade (Wogerbauer et
al., 2016), but this may not be indicative of the overall stock situation. The latest assessment by ICCAT (2015)
suggests that the stock is not over-fished and is above the level that is consistent with maximum sustainable
yield.
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Human impacts
There are no large-scale directed fisheries for blue sharks but they are a major bycatch of longline and
driftnet fisheries for tunas and billfish, where they can comprise up to 70% of the total catches and thereby
exceed the actual catch of targeted species (ICCAT, 2005). Much of this bycatch is often unrecorded. Since
1998 there has been a Basque artisanal longline fishery targeting blue shark and other pelagic sharks in the
Bay of Biscay (Díez et al., 2007). Observer data indicated that substantially more sharks are caught as bycatch
than reported in catch statistics.
It is difficult to accurately quantify landings of blue shark in the North Atlantic, as data can be incomplete,
and generic reporting of shark catches has resulted in under-estimation. Landings data from different
sources (ICCAT, FAO and national statistics) vary significantly. Regardless, estimated North Atlantic
landings were in the region of 30,000t from 1997 to 2007. Since then estimated landings have increased
significantly.
Blue sharks are also caught in considerable numbers in recreational fisheries. These fisheries are mainly
catch and release in the Northeast Atlantic but in the Northwest Atlantic blue sharks are frequently landed
by anglers.
Management/Conservation
There are no measures regulating the catches of blue shark in the North Atlantic.
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SHELF AND COASTAL SPECIES
Squatina squatina (Linnaeus, 1758)
Angel shark
Irish name: Bráthair
Status
Ireland: Critically endangered A2bd. NE Atlantic: Critically endangered. A2bcd+3d. Global: Critically
Endangered A2bcd+3d.
Justification
Numbers of angel sharks (Squatina squatina) encountered in tagging programmes conducted by anglers and
Inland Fisheries Ireland show a decline of over 90% since the 1980s (Wogerbauer et al., 2014). This warrants a
critically endangered listing.
Range, distribution and habitat
This species’ range encompasses the Atlantic coasts of Europe from Ireland and Britain to Morocco, the
Canaries, the Mediterranean coasts of Europe, Africa and the Levant, and the Black Sea (Whitehead et al.,
1984). Tagging data from Inland Fisheries Ireland show that Tralee Bay is the main centre of its distribution
in Ireland, (>90% of total tagged), with Clew Bay a secondary area. This species is known to make extensive
migrations southwards from the Tralee Bay area to the Celtic Sea shelf and Bay of Biscay (Fitzmaurice et al.,
2003a). The species may overwinter in St. George’s Channel (ICES, 2014b). Recent reports of angel sharks
have also been received from inner Galway Bay (Peter Tyndall, pers. comm.).
Biology and Ecology
A medium bodied shark which has a skate-like appearance. It reaches up to 2.5m TL. It inhabits sandy and
muddy bottoms, in shallow depths of 5-100m (Whitehead et al., 1984). Angel shark is live bearing, producing
7-25 embryos. Its gestation period is 10 months and neonates are 20-30cm TL (Roux, 1984).
Trend
Numbers tagged and recaptured since the 1980s, in a tagging programme conducted by anglers working
with Inland Fisheries Ireland, show a decline of over 95%. Even in its core area of Tralee Bay, few angel
sharks have been encountered in the last 15 years.
Human impacts
This species is especially vulnerable to coastal fisheries using static nets. In Tralee Bay, one of its main
centres, it is particularly vulnerable to static net fisheries targeting crustaceans (BIM, 2012). It is also an
occasional by-catch in mixed trawl fisheries, particularly in St. George’s Channel.
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Management/Conservation
It is prohibited to fish for, land or tranship this species under EC fisheries management legislation. This is
the highest conservation designation afforded under the Common Fisheries Policy. It is protected in
Northern Ireland Inshore Waters out to 6 nautical miles.
Rostroraja alba (Lancepède, 1803)
White skate
Irish name: Sciata bán
Status
Ireland: Critically endangered A2bd. NE Atlantic: Critically Endangered A2bd. Global: Endangered
A2cd+4cd.
Justification
Declines in geographical range have occurred in the Northeast Atlantic and anecdotal evidence suggests this
species, including localized populations have been extirpated. Only two locations have yielded confirmed
reports of this species in recent years, both on the west coast of Ireland.
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Range, distribution and habitat
It ranges, in the Atlantic, from western Ireland to South Africa, extending through the western
Mediterranean to Tunisia and western Greece. It also occurs in the southwest Indian Ocean (Stehmann and
Burkel, 1984a). It occurs on sandy bottoms in coastal waters to the upper slope region between about 40 to
400 m and exceptionally down to 500m (Capape 1976, Stehmann and Burkel 1984a, Serena 2005). In Ireland
the species is confined to the Tralee Bay region and to a lesser extent, Galway Bay (Varian et al., 2011) and
these are the only known refuges for the species in the north east Atlantic.
Biology and Ecology
This is a large bodied, slow growing and late maturing species (Kadri et al., 2014). Maximum recorded size is
200cm TL (Bauchot 1987). Estimates of total length at maturity varied between two studies from North
Africa: 130cm (males) and 120cm (females) (Capapé, 1976) and 119cm for males, and 129cm for females
(Kadri et al., 2014). These authors report age at maturity as 20 and 23 years, for males and females, and the
oldest male reported in that study was 32 years, whereas the oldest female was 35 years. The longevity was
estimated at 51 and 76 years for males and females, respectively. A captive white skate at the Galway
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aquarium laid an egg at the age of 7, though this may not be indicative of conditions in the wild (Burke, pers.
comm.). Gestation period may be about 15 months (Stehmann and Burkel 1984a) and females produce
between 55 and 156 ova per year (Serena 2005), with 1-2 egg capsules reported to be contained in each
female’s oviducts at a time (Kadri et al. 2014).
Trend
No information is available.
Human impacts
This species is especially vulnerable to coastal fisheries using static nets. In Tralee Bay, one of its known
refuges, it is particularly vulnerable to static net fisheries targeting crustaceans.
Management/Conservation
It is prohibited to fish for, land or tranship this species under EC fisheries management legislation. This is
the highest conservation designation afforded under the Common Fisheries Policy.
Dipturus batis complex A (= flossada) (Linnaeus, 1758)
Common Skate
Irish name: Sciata coiteann
In a revision of European rajids, Clark (1926) recognised Raja batis (Raia batis) as valid and Raja intermedia
Parnell, 1837 as a junior synonym, hence blue skate was combined with flapper skate. This grouping
remained until 2010 when separate species were re-established (Iglesias et al., 2010; Griffiths et al., 2010). Blue
skate are distinguished morphologically from flapper skate by several diagnostic characteristics reported in
Iglesias et al. (2010) and genetically in Griffiths et al. (2010). The revised nomenclature remains to be accepted
by the International Commission on Zoological Nomenclature (ICZN). Therefore they are referred to here as
the, smaller-bodied, blue skate (D. batis-complex A, = D. cf. flossada of Iglesias et al. 2010) and the larger-
bodied flapper skate (D. batis-complex B; = D. cf. intermedia of Iglesias et al. 2010). Much of the distributional
and biological information collected from 1926 to 2010 relates to the complex, and little species-specific data
exist. For this reason, records for the two species, combined are displayed below, and records for each
individual species shown thereafter.
Status
Ireland: Critically Endangered A2 bcd. NE Atlantic: Critically Endangered A2 bcd. Global: Critically
Endangered A2 bcd.
Justification
The species complex is susceptible to exploitation due to its large size, aggregating behaviour, low
productivity and late age at maturity. The reasons for the declines documented in the literature have not
ceased. For these reasons the species is assessed as Critically Endangered.
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Range, distribution and habitat
Historical distribution data are confounded by misidentification and taxonomic issues though the blue skate
appears to have a more southerly distribution that the flapper skate (Griffiths et al., 2010). The historical
geographical range of D. batis-complex may have covered much of the continental shelf of the Northeast
Atlantic, from Madeira and the coast of northern Morocco in the south, to Iceland in the north (Stehmann
and Bürkel 1984a). At the start of the twentieth century it was considered to have a wide distribution over
the shallower waters of the continental shelf surrounding the British Isles, albeit more common in western
regions (Walker and Heessen 1996). Though individual specimens are reported very occasionally from the
Irish Sea, outer Bristol Channel and central and northern North Sea, the current range tends to occupy the
deeper waters off Iceland, the western seaboard of the British Isles, including the Celtic Sea, along the edge
of the continental shelf, and in the Bay of Biscay and Atlantic Iberian waters (ICES 2010, 2012). The species’
northerly limits are not known precisely, however confirmed specimens are known from Iceland, Rockall
Bank and the western Isles off Scotland (58oN). The bathymetric ranges of the species are poorly known
generally, as is their western distribution ranges, but blue skate has been taken from depths between 54 and
422m (Griffiths et al., 2010; ICES 2013).
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Biology and Ecology
Historical life history data are confounded by misidentification and taxonomic issues. The length at 50%
maturity is estimated to be 115.0 and 122.9cm total length for male and females, respectively (Iglesias et al.,
2010). The age at 50% maturity is estimated as 11 years (Iglesias et al., 2010). The maximum lengths and
weight (eviscerated) observed by Iglesias et al. (2010) were 143.2cm and 15.2kg. Based on records of egg cases
of Dipturus batis complex, Tralee and Dingle Bays are nurseries (Varian et al., 2011). Other refuges of the
complex include Lough Swilly, north Antrim, Clew, Killala and Galway Bays (Fitzmaurice et al., 2003c).
Dipturus batis-complex preys mostly on crustaceans and teleost fish, but it is also a predator of sharks and
rays (Steven, 1947), suggesting that its decline may affect populations of smaller-bodied rays.
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Trend
Although there is little information on either species in the Dipturus batis complex, the complex as a whole is
considered to be depleted in the waters around Ireland. Individuals are now rarely recorded in surveys
(ICES, 2014) although they are regularly captured in inshore waters in specific areas.
Human impacts
Common skate was historically one of the most abundant and widely distributed skates in the northeast
Atlantic; in the late 19th Century it was described as very common in inshore areas of the western English
Channel, and at least as common as smaller Raja species (Heape 1887). Catch rates of this species in this area
declined during the 20th century. By the 1920s it was uncommon in inshore areas of the Western English
Channel and by the 1970s common skate was considered extirpated from the Irish Sea (Brander 1981). They
also disappeared from the southern and central North Sea (Walker 1999, Rogers and Ellis 2000), although
individual specimens are reported occasionally from these areas (e.g., Ellis et al., 2002, Ellis et al., 2005). It has
been taken in targeted fisheries where/when abundant, and continues to be a bycatch elsewhere within its
range.
Management/Conservation
It is prohibited to fish commercially for, land or tranship this species under EC fisheries management
legislation. This is the highest conservation designation afforded under the Common Fisheries Policy. It was
removed from the Irish Specimen Fish Committee listings in 1976 due to an observed decline in numbers. It
has gradually recovered and in 2016 was restored to the ISFC list of eligible species for catch and release,
primarily to facilitate the collection of distribution data. In Northern Ireland it is illegal to deliberately fish
for common skate within 6 nautical miles of baseline. A small number of anglers have been issued with
licences to tag and release them for scientific purposes.
Dipturus batis complex B (= intermedia) Parnell, 1837
Flapper skate
Irish name: Sciata coiteann
In a revision of European rajids, Clark (1926) recognised Raja batis (Raia batis) as valid and Raja
intermedia Parnell, 1837 as a junior synonym, hence blue skate was combined with flapper skate. This
grouping remained until 2010 when separate species were re-established (Iglesias et al. 2010; Griffiths et al.
2010). Blue skate are distinguished morphologically from flapper skate by several diagnostic characteristics
reported in Iglesias et al. (2010) and genetically in Griffiths et al. (2010). The revised nomenclature remains to
be accepted by the International Commission on Zoological Nomenclature (ICZN). Therefore they are
referred to here as the, smaller-bodied, blue skate (D. batis-complex A, = D. cf. flossada of Iglesias et al. 2010)
and the larger-bodied flapper skate (D. batis-complex B; = D. cf. intermedia of Iglesias et al. 2010). Much of the
distributional and biological information collected from 1926 to 2010 relates to the complex, and little
species-specific data exist.
Status
Ireland: Critically Endangered A2 bcd. NE Atlantic: Critically Endangered A2 bcd. Global: Critically
Endangered A2 bcd.
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Justification
The species complex is susceptible to exploitation due to its large size, aggregating behaviour, low
productivity and late age at maturity. The reasons for the declines documented in the literature have not
ceased. For these reasons the species is assessed as “Endangered”.
Range, distribution and habitat
Historical distribution data are confounded by misidentification and taxonomic issues though the flapper
skate appears to have a more northerly distribution that the blue skate (Griffiths et al., 2010). The historical
geographical range of D. batis-complex may have covered much of the continental shelf of the North-east
Atlantic, from Madeira and the coast of northern Morocco in the south, to Iceland in the north (Stehmann
and Bürkel 1984a). At the start of the twentieth century it was considered to have a wide distribution over
the shallower waters of the continental shelf surrounding the British Isles, albeit more common in western
regions (Walker and Heessen 1996). Though individual specimens are reported very occasionally from the
Irish Sea, outer Bristol Channel and central and northern North Sea, the current range tends to occupy the
deeper waters off Iceland, the western seaboard of the British Isles, including the Celtic Sea, along the edge
of the continental shelf, and in the Bay of Biscay and Atlantic Iberian waters (ICES 2010, 2012). Based on
records of egg cases of Dipturus batis complex, Tralee and Dingle Bays are nurseries (Varian et al., 2011).
However other nurseries are likely to exist. Other refuges of common skate sensu D. batis include Lough
Swilly, Antrim, Clew, Killala and Galway Bays (Fitzmaurice et al., 2003c). Historically, common skates were
also taken by recreational anglers in Befast and Strangford Loughs and Lough Foyle.
Biology and Ecology
Historical life-history data are confounded by misidentification and taxonomic issues. The length at 50%
maturity is estimated to be 185.5 and 197.5cm total length for male and females, respectively (Iglesias et al.,
2010). The age at 50% maturity is estimated as 19-20 years (Iglesias et al., 2010). The maximum lengths and
weight (eviscerated) observed by Iglesias et al. (2010) were 228.8cm and 78kg. Electronic tagging tagging
studies have revealed that the species exhibits pronounced site fidelity to highly localised areas (Wearmouth
and Sims, 2009).
Trend
Although there is little information on either species in the Dipturus batis complex, the complex is considered
to be depleted in the waters around Ireland. Individuals are now rarely recorded in surveys (ICES, 2014)
though it is still regularly taken by recreational anglers in certain areas.
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Human impacts
Common skate was historically one of the most abundant and widely distributed skates in the northeast
Atlantic, though catch rates of this species in this area declined during the 20th century. By the 1970s
common skate was considered extirpated from the Irish Sea (Brander 1981), and they also disappeared from
the southern and central North Sea (Walker 1999, Rogers and Ellis 2000). Though individual specimens are
reported occasionally from these areas (e.g., Ellis et al. 2002, Ellis et al. 2005), Flapper skate are now only
regularly observed off northern and north-western Scotland, along the edge of the continental shelf (>150 m
depth) and in relatively low numbers in the Celtic Sea (only 8 of 1201 D. batis-complex were identified as
Flapper skate; ICES 2012). Though there are currently no target fisheries for these species they may be
caught as bycatch in mixed demersal fisheries and mortality rate of discarded skates in unknown.
Management/Conservation
It is prohibited to fish for, land or tranship this species under EC fisheries management legislation. This is
the highest conservation designation afforded under the Common Fisheries Policy. In Northern Ireland it is
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illegal to deliberately fish for common skate within 6 nautical miles of baseline. A small number of anglers
have been issued with licences to tag and release them for scientific purposes.
Squalus acanthias Linnaeus, 1758
Spurdog
Irish name: Fíogach gobach
Status
Ireland: Endangered A2bd. NE Atlantic: Endangered A2bd. Global: Vulnerable A2bd+3bd+4bd.
Justification
A new stock assessment for the Northeast Atlantic stock estimates a decline in biomass of 81% from initial
levels (ICES, 2014a). This assessment shows that spurdog (Squalus acanthias) in Irish waters meets the criteria
for Endangered, A2bd.
Range, distribution and habitat
This is a small bentho-pelagic shark of temperate continental shelf seas worldwide (Compagno, 1984). In
Irish waters, the spurdog belongs to the northeast Atlantic population, which stretches from Portugal to
Norway, including the North Sea (ICES, 2014b). It occurs from coastal waters to depths of 900 m, but mostly
in waters of less than 200m deep. Usually coastal and demersal, they migrate north and south as well as near
shore and offshore in waters of 7 to 15°C water (Compagno 1984). This is a bentho-pelagic species. It is not
known to associate with any particular habitat (McMillan and Morse 1999).
Spurdog are thought to mate in winter (Castro 1983, Compagno 1984). Possible mating sites have been
suggested in the central Irish Sea, the southern Celtic Sea and the east coast of England (Dureuil, 2013). Vince
(1991) found evidence for the presence of larger females and males in the North Sea, and Holden (1965)
found females larger than 80 cm northeast of Scotland in summer. Hickling (1930) reported spawning
grounds from the west of Ireland and the Celtic Sea, and Fahy (1988) confirmed that inshore waters off
southwest Ireland, particularly the mouth of the Shannon, were a spawning ground. Vince (1991) suggested
that females might give birth in the eastern Celtic Sea and Holden (1965) reported parturition to occur along
the Norwegian coast and north of Scotland. Dureuil (2013) found the highest numbers of pups northwest of
Scotland, based on survey data from 1985-2012.
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Biology and Ecology
In the Northeast Atlantic, spurdog mature at 74 to 92.5cm (females) and 57.5 to 64cm (males) (Holden and
Meadows 1962, Sosinski 1978, Fahy 1989, Henderson et al., 2002). The maximum age is at least 40 years (Fahy
1989). The gestation period ranges from 18 to 25 months (Ford 1921, Gauld 1979, Jones and Ugland 2001) and
breeding takes place every other year (Holden and Meadows 1962, Sosinski 1978, Fahy 1989). Fecundity
increases with size (Ellis and Keable 2008). The embryonic development starts in November (Ford, 1921).
The length at birth ranges from 19-31cm (Ford 1921, Gauld 1979) and pupping occurs from late August to
December (Ford 1921, Holden and Meadows 1962, Gauld 1979, Jones and Ugland 2001). Copulation is
assumed to occur offshore soon after the females give birth (Holden 1965). In accordance, Jones and Ugland
(2001) observed fertilization from October to February.
Trend
A new stock assessment for the Northeast Atlantic stock provides an estimated decline in total biomass of
81% from initial levels. The updated ICES assessment is based on a new population model with density
dependence incorporated.
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Human impacts
This species was targeted by Irish gillnetters off western Ireland, Norwegian longliners in the North Sea and
UK longliners in the Irish Sea. These fisheries have all ceased. However the species continues to be taken as a
by-catch particularly in mixed demersal fisheries. It was formerly also a by-catch in coastal driftnet fisheries
for salmon in Irish waters and an accidental catch in mid-water trawling targeting herring. Spurdog are
targeted by anglers operating on a catch and release basis.
Management/Conservation
This species is subject to a zero tonne TAC under EC legislation since 2011. This measure is not entirely
effective, as unavoidable by-catch is discarded. However the measure disincentivises intentional targeting of
spurdog as either a clean catch or as part of mixed catches.
Raja undulata Lancepède, 1802
Undulate Skate
Irish name: Roc dústríoctha
Status
Ireland: Endangered B1abi)iv). NE Atlantic: Near Threatened. Global: Endangered A2bd+3d+4bd.
Justification
Its patchy distribution means that populations are widely separated, probably with little exchange. In the
areas where it is known to be locally common, available data suggest declines have occurred. The extent of
occurrence of R. undulata in Irish waters is severely restricted and its distribution is limited to Tralee Bay and
the immediate vicinity. There is sufficient information to show that it does not warrant any designation other
than “Endangered”.
Range, distribution and habitat
The undulate skate is a medium-sized, inshore skate that has a patchy distribution in the northeast and
eastern central Atlantic, with discrete areas where it may be locally common (southwestern Ireland, eastern
English Channel, southern Portugal). It also occurs in the Mediterranean Sea, where it appears to be rare.
The Undulate Skate occurs in shelf waters down to about 200 m depth, although it is more common in
shallow waters.
In Irish waters the undulate skate distribution is centred on Tralee Bay (Varian et al., 2011) with records
southward to Mizen Head and northward to the Aran Islands (Fitzmaurice et al., 2003f; Ellis et al., 2012).
Over 99% of all undulate skate tagged in Ireland (1972-2014) were from Tralee Bay (Wogerbauer et al., 2014).
The population in Ireland is isolated from other populations in the Atlantic (ICES, 2014a,b).
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Biology and Ecology
In the neighbouring Normano-Breton Gulf stock which is comparable in characteristics, the length-at-
maturity (L50) has been preliminarily estimated as 78cm and 82cm for males and females, respectively
(Stéphan et al., 2014). The observed length range was from 1899cm for males and 18-103cm for females
(Stéphan et al., 2014). Combined data from the North Sea and Celtic Sea ecoregions indicate a length-at-first-
maturity of 80cm and 79cm for males and females respectively, and a length-at-maturity (L50) of 83cm TL for
males (McCully et al., 2012). The observed length range was 2289cm TL and 1760cm TL for males and
females, respectively (McCully et al., 2012). Throughout the species’ range neonates, juveniles and egg-laying
females have been observed in estuarine and lagoon habitats.
Trend
An index of fish tagged and recaptured by Inland Fisheries Ireland shows a decline of 60-80% since 1981
(ICES, 2014). However, the trend since 2006 may be confounded due to reduced angling effort arising from a
reduction in the size of the local angling charter fleet.
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Human impacts
As a coastal and inner shelf species it is susceptible to bycatch of trawl and gill net fisheries. It is particularly
vulnerable to static net fisheries, targeting shell fish, in its core range in Tralee Bay. The majority of tagged
undulate skate recaptures from 1970 to 2014 was due to recreational angling (operating on a catch and
release basis), but at least 28% were attributed to commercial fishing (Wogerbauer et al., 2014).
Management/Conservation
This species is managed as an exception to the generic skate and ray total allowable catch (TAC) under the
EU CFP. It must not be be targeted, when accidentally caught, it must not be harmed but released
immediately.
Dasyatis pastinaca (Linnaeus, 1758)
Common Stingray
Irish name: Roc an gha nimhe coiteann
Status
Ireland: Endangered B1, B2a, biii. NE Atlantic: Vulnerable A2d. Global: Data deficient.
Justification
The common stingray has a patchy distribution in Irish waters and is known to occur seasonally in Tralee
Bay. This apparently represents an isolated population, and given its small extent of occurrence and area of
occupancy it warrants being classified as “Endangered”.
Range, distribution and habitat
The common stingray is a wide ranging species throughout the Eastern Atlantic, occurring from southern
Norway southwards to the Mediterranean and Black Seas, and onwards via the Canaries to South Africa. It
occurs from the shore to about 200m depth, but is more commonly found in shallow waters (<50m).
In the Northeast Atlantic the common stingray is less abundant than in the Mediterranean and has
reportedly disappeared from the Bay of Biscay. Although the species has been recorded from all around the
Irish coast, it seems to be more common, at least locally, in the south and south-west. Almost 84% of all the
rod and line caught specimen common stingray (weighing 13.6kg) recorded by the Irish Specimen Fish
Committee (ISFC) since 1960 were captured in Tralee Bay.
Biology and Ecology
Life-history data for the common stingray in the Northeast Atlantic is not available. In the Eastern
Mediterranean the maximum age observed was 10 years and the parturition time of common stingray
occurred in summer (from May to September) (Ismen, 2003). Males matured at 43cm TL (22cm disc width
(DW)) and females at 46cm TL (24cm DW). The maximum reported size is 140cm DW and 250cm TL (Serena
et al., 2009).
Trend
No information is available.
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Human impacts
The seasonally shallow depth distribution makes the common stingray more vulnerable to small-scale
inshore fisheries than to offshore trawling. Sting ray specimens are caught by anglers, operating on a catch
and release basis, in shallow waters from April to September.
Management/Conservation
There are no measures in place for this species.
Dipturus oxyrinchus (Linnaeus, 1758)
Long nosed skate
Irish name: Sciata socfhada
Status
Ireland: Vulnerable, A2bd. NE Atlantic: Near Threatened. Global: Near Threatened.
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Justification
The low abundance of this species throughout recorded history and its current rarity in Irish waters makes it
very difficult to classify. There have been no records in Irish shelf waters since 2008. It is recorded in low but
stable numbers on the Rockall Bank, however the time series in that area is short (1999-present). Given that
there is a slight apparent decline per year in surveys, with probability of capture lessening over time and
given that exploitation in mixed demersal and deepwater fisheries is still ongoing, a designation of
Vulnerable (A2bd) seems the most applicable. However there is a danger that this species may be up-listed
in future so extra attention is required.
Range, distribution and habitat
Long nosed skate is endemic to the Northeast Atlantic and Mediterranean, though the populations in each
area are known to be genetically distinct (Griffiths et al., 2011). It occurs in the Atlantic from southern
Norway, the Shetlands, Faroe Islands and Rockall Bank south to the Canaries. Its range extends round the
entire Mediterranean margin, and it is a demersal species occurring in a wide range of depths from 90-900m
(Stehmann and Burkel, 1984a). It is unclear if the skates on the Rockall Bank and those previously recorded
from Irish shelf waters are from the same population, though there are no natural barriers for a deep-sea
species like this.
Biology and Ecology
The biology of this large bodied skate is poorly known. It is egg laying with the spawning season stretching
from spring to early summer. It reaches up to 150cm TL (Stehmann and Burkel, 1984a). Length at maturity is
estimated as 83cm TL for males and 104cm TL for females. Both sexes are estimated to reach sexual maturity
from 6-8 years (Serena et al. 2011). The estimated longevity off Tunisia is 26 and 38 years for males and
females, respectively (Kadri et al., 2015).
Trend
Between the late 1960s and 2002 UK ground fish surveys very occasionally reported this species in very low
numbers in the Celtic Sea and off southwest Ireland at depths of 111−159m (Ellis et al. 2005). There have been
no recent reports from those surveys, and only 6 records from the Irish Groundfish Survey (begun 2003)
with none since 2008. It is known to occur in small but stable numbers on the Rockall Bank (UK-Scotland
surveys) and in Norwegian and Biscayan waters. An unconfirmed report of an egg case from Barley Cove,
Co. Cork has been shown to have been instead a blue skate (Sarah Varian, pers. comm.). This species has
been reported extinct in the Irish Sea (Dulvy et al., 2000), though this is contested by Ellis et al. (2002) who
argue that it never occurred there. The lack of recent records from Irish shelf waters leads to concerns that
this species may be mis-classified. Extra attention is required to obtain a better classification of this species
by the time of the next Red List process.
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Human impacts
Because of its wide depth range it is vulnerable as a by-catch in almost all mixed demersal fisheries,
including deepwater fisheries on the slopes of the continental shelf and the Rockall Bank.
Management/Conservation
There are no management or conservation measures in place for this species.
Leucoraja naevus (Müller and Henle, 1841)
Cuckoo ray
Irish name: Roc na súl dubh
Status
Ireland: Vulnerable A2bd. NE Atlantic: Least concern. Global: Least concern.
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Justification
Abundance indices from trawl surveys show an overall decline of about 45% since the 1990s. This implies
that a listing of Vulnerable is warranted.
Range, distribution and habitat
Leucoraja naevus is a small-bodied skate with a wide geographic distribution in the Northeast Atlantic and
Mediterranean Sea (Stehmann and Bürkel, 1984a; Ellis et al. 2005). In Atlantic waters the species occurs off
coasts northward from the Shetland Isles and southern Norway in the north, to Morocco in the south, and
also reported from Senegal (Stehmann and Bürkel 1989).
ICES considers that a single population is found in Irish waters, and includes the Irish and Celtic Seas,
Biscay, the west of Ireland and Scotland (ICES, 2014a,b). However, further analyses by Moriarty et al. (2015)
suggest that the population to the west and north of Ireland is separate from that in the Irish/Celtic Seas and
in Biscay. The Causeway coast was a hotspot for the species for recreational boat anglers with occasional fish
recorded off the south coast.
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Biology and Ecology
The length-at-maturity (L50) in the Celtic seas has been estimated as 57.3cm TL and 59.8cm TL for males and
females, respectively (McCully et al., 2012). The observed length range was 1172cm TL and 1069cm TL for
males and females, respectively (McCully et al., 2012). Age at maturity for females and males is estimated at
7.4 years and 6.8 years, respectively, in the North Sea (Walker 1999). In the Irish Sea the length and age at
50% maturity for males and females was reported as 56.9 and 56.2cm TL and 4.2 and 4.3 years, respectively
(Gallagher et al., 2005). Juvenile L. naevus have been observed to be abundant in the southern Irish Sea and St
George's Channel and in the Celtic Sea (Ellis et al., 2005).
Cuckoo skate is found on the continental shelf and slope at depths of 20-500m. It is typically an offshore
species, occurring further offshore than, for example, spotted skate and thornback skate. It is abundant on
coarse sand/gravel substrates in the Irish Sea and western English Channel. The scarcity of egg case records
on the coast (Varian et al., 2011) implies that its nurseries are off shore.
Trend
The population around Ireland, the Celtic Sea and Bay of Biscay shows an overall decline over time. There is
evidence that the species is being over-exploited in relation to sustainable fishing rates in this area (ICES,
2014).
Human impacts
This species is widely taken as retained bycatch in mixed demersal fisheries through much of its range,
smaller specimens are also discarded. It is vulnerable to capture in many offshore demersal mixed fisheries.
Due to it occurring further offshore than other skates (e.g. blonde and thornback skates), it is of less
importance to recreational fisheries.
Management/Conservation
This species is managed as part of the generic maximum total allowable catch (TAC) for named skate
species, in the waters west of the British Isles. The Irish Specimen Fish Committee (ISFC) reduced the cuckoo
skate specimen weight to 1.8kg in 2010 following a sustained decline in the numbers of specimens being
recorded since the late 1980s (ISFC, unpublished). No response has been observed in terms of increased
returns.
Leucoraja circularis (Couch, 1838)
Sandy Skate
Irish name: Roc gainmheach
Status
Ireland: Near Threatened. NE Atlantic: Endangered A2bcd. Global: Endangered A2bcd.
Justification
The relatively large body-size (120cm) would indicate that this species is susceptible to over-fishing. Given
the very low (but stable over the last decade) catch levels in the Porcupine Bank survey, and the declines in
catches outside Irish waters this species is classified as “Near Threatened” in Irish waters. There is evidence
that the population on the Porcupine Bank may be an isolated one, and therefore further attention is
required for this species in the future.
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Range, distribution and habitat
Sandy skate (Leucoraja circularis) is a medium-bodied skate found in the northeast Atlantic and
Mediterranean (Stehmann and Bürkel, 1984a). It is primarily encountered on the northwest and west edges
of the Porcupine Bank. It appears to be a rare species and given the limited number of authenticated records,
the exact distribution is uncertain. However ICES considers a single population to exist in the waters west
and southwest of Ireland (ICES, 2014a,b).
Biology and Ecology
The life-history characteristics of this species are unknown in the northeast Atlantic. The maximum recorded
size is 120cm TL (Serena 2005).
Trend
There is insufficient information, because this species is not well selected in most surveys. However catch
rates from the Spanish trawl survey on the Porcupine Bank are stable at a low level. These data are not
considered to be a reliable indicator of trends in population over time however (ICES, 2014).
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Human impacts
This species is a bycatch in mixed trawl fisheries operating in the outer parts and edge of the continental
shelf. The relatively large body-size (120cm) would also indicate that this species is vulnerable to over-
fishing. Due to its offshore habitat preference, it is of no importance to recreational fisheries.
French landings data for this species have declined from about 500 tonnes per year in the early 1990s to less
than 40 tonnes in 2012, although there is concern over species identification and the quality of species-
specific data. Species-specific landings data prior to this are not available. English surveys in the North Sea
and Celtic Sea have not recorded this species since 1996 and 1997 respectively, although it is still recorded in
various Scottish surveys around northwestern Scotland and on the Porcupine Bank. Most of the recent
captures of this species in Scottish surveys have been made in waters of 180500m depth, suggesting that the
main part of the distribution is now in deeper water, along the edge of the continental shelf and on offshore
banks.
Management/Conservation
This species is managed as part of the generic maximum total allowable catch (TAC) for named skate
species, in the waters west of the British Isles.
Leucoraja fullonica (Linnaeus, 1758)
Shagreen Skate
Irish name: Roc úcaire
Status
Ireland: Vulnerable A2bd. NE Atlantic: Vulnerable A2bd. Global: Vulnerable A2bd.
Justification
Downward trends in survey indicators of abundance imply that a Vulnerable listing is warranted.
Range, distribution and habitat
The Shagreen skate (Leucoraja fullonica) is a medium-bodied skate found in the Northeast Atlantic and
Mediterranean (Stehmann and Bürkel, 1984a). It is an offshore species, usually occurring on the outer parts
of the continental shelf, at depths of 30550m (Stehmann and Bürkel, 1984a). In Atlantic waters it is
distributed from Madeira and northern Morocco northwards to Iceland, Faeroe Islands and Norway,
including the Skagerrak (Stehmann and Burkel 1984a). It is also present but rare in the Norwegian Sea,
Icelandic waters and east of Greenland (ICES 2012). It has not been encountered in the North Sea in recent
years, and West of Scotland, including at Rockall Bank, Shagreen skate now only appears occasionally in
surveys (ICES 2012), however, it may be distributed outside some of the areas covered by such
internationally coordinated surveys. From similar survey catches, the species is also known to exist in low
numbers in the Bay of Biscay region, Iberian waters and around the Azores and mid-Atlantic ridge.
However ICES considers a distinct population to exist in the waters west and southwest of Ireland (ICES,
2014a,b).
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Biology and Ecology
McCully et al. (2012) reported a small number of specimens (n=34); 17 males (2196cm TL) and 17 females
(2470cm TL). All 17 females were immature, but two of the larger males (75 and 96cm TL) were mature the
largest immature male was 82cm TL. Nothing else is known about the life-history of this species.
Trend
Catch rates from the French trawl survey in the Celtic Sea show a decline of about 65% since the late 1990s
(ICES, 2014).
Human impacts
This species is a bycatch in mixed trawl fisheries operating in the outer parts and edge of the continental
shelf.
Management/Conservation
This species is managed as part of the generic maximum total allowable catch (TAC) for named skate
species, in the waters west of the British Isles
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Tetronarce nobiliana Bonaparte, 1835
Electric ray
Irish name: Roc nimhe
Status
Ireland: Near Threatened. NE Atlantic: Least concern. Global: Data deficient.
Justification
This is a rare species that is only infrequently encountered. The exact status of this species is unknown and
given the paucity of data, viviparous breeding and large body size of the species it is classified as “Near
Threatened”.
Range, distribution and habitat
This species has a wide distribution in the Northeast Atlantic, occurring from Ireland and the UK to Morocco
and the Mediterranean Sea (Stehmann and Bürkel 1984). It is usually found at depths ranging from 10-150m
but specimens have been recorded down to 800m.
Biology and Ecology
Little is known about the biology or ecology of this species in the Northeast Atlantic. Unlike other ray
species occurring in Irish waters it is benthopelagic, swimming in the water column and migrating over long
distances (Stehmann and Bürkel 1984). A viviparous species, it reaches a maximum size of about 180cm total
length (TL) (McEachran and Carvalho 2002). Up to 60 embryos have been reported in large females,
gestation period is about 12 months and size at birth is 20-25cm TL (McEachran and Carvalho 2002). In the
Mediterranean Sea the smallest adult male was reported to be 55cm TL, whereas the smallest female was
90cm TL (Capapé et al., 2006).
Trend
No information is available.
Human impacts
As a coastal and inner shelf species it is susceptible to bycatch of trawl and gill net fisheries. It is not
consumed and is usually discarded, resulting in limited catch data. Further research is required to determine
the impact of fishing activities on the species.
Very few data are available on population or catch trends from scientific surveys, although surveys suggest
that this species is rarely caught. Went (1978) noted captures from the south and west coasts and single
specimens from the north-west and the Irish Sea. Only four specimen electric ray (specimen weight is ≥ 9.072
kg) have been reported to ISFC from 1977 to 2015. The most recent was in 2002 and all were taken in summer
months (August and September) with three being taken on the south coast.
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Management/Conservation
There are currently no EU limits on landings or proposals for management of this species.
Raja brachyura Lafont, 1873
Blonde Skate
Irish name: Roc fionn
Status
Ireland: Near Threatened. NE Atlantic: Near Threatened. Global: Near Threatened.
Justification
As a coastal and inner shelf species it is a bycatch of trawl and gill net fisheries. Although locally abundant
in some areas, survey data indicate that declines may have occurred. This species, like other relatively large
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57
skates, is slow growing making it vulnerable to depletion. Given observed and inferred declines, and
continued high levels of exploitation, this species is assessed as “Near Threatened”.
Range, distribution and habitat
Raja brachyura (blonde skate) is a medium-bodied skate species with a wide geographic distribution in the
Northeast Atlantic and Mediterranean Sea (Stehmann and Bürkel, 1984a). It is relatively common in the
inshore and shelf waters (down to about 150m) in the English Channel and Irish Sea, Bristol Channel and St
George’s Channel (Fahy 1989, 1991; Ellis et al., 2005a).
The species is often associated with sandbanks and commonly occurs from 14146m (Ellis et al., 2005). In the
Irish and Celtic Sea R. brachyura has a patchy distribution but can be locally abundant on particular grounds.
ICES considers that a single population exists off Ireland, encompassing the Irish and Celtic Seas and the
Bristol Channel.
Biology and Ecology
Combined data from the North Sea and Celtic Sea ecoregions indicate length-at-maturity (L50) of 78.2cm TL
and 85.6cm TL for males and females, respectively (McCully et al., 2012). The observed length range was 13
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100cm TL and 12102cm TL for males and females, respectively (McCully et al., 2012). The connectivity
among stocks in these ecoregions is unknown. In the Irish Sea the length and age at 50% maturity for males
and females was reported as 81.9 and 83.7cm TL and 4.6 and 5.5 years, respectively (Gallagher et al., 2005).
Juvenile R. brachyura have been recorded in the Bristol Channel, Cardigan Bay and Irish Sea, and off Poole
and in Start Bay within the English Channel (Ellis et al., 2005). Egg case records suggest that the south coast
from Tralee Bay to Waterford constitute nurseries (Varian et al., 2011).
Trend
The only trend information available is for juveniles, and shows an increase over time. There is no
information on adult population trends, but available evidence suggests that the population is over-
exploited. Specimen fish numbers from 1954 2015 (Irish Specimen Fish Committee reports) show periodic
peaks in abundance since the 1960s with a decline observed since the late 2000s.
Human impacts
As a coastal and inner shelf species it is a by-catch of trawl and gill net fisheries in the Irish Sea, Celtic Sea
and in the Bristol Channel. Other landings come from inshore fisheries on the south, west and northwest
coasts. As one of the larger species in the skate complex, it may be targeted in some local, seasonal fisheries.
Management/Conservation
This species is managed as part of the generic maximum total allowable catch (TAC) for named skate
species, in the waters west of Ireland and the UK.
Scyliorhinus stellaris (Linnaeus, 1758)
Bull huss
Irish name: Fíogach mór
Status
Ireland: Least concern. NE Atlantic: Near Threatened. Global: Near Threatened.
Justification
Given upward trends in its abundance, likely high reproductive output and not being vulnerable to
commercial fisheries, a designation of Least Concern is warranted.
Range, distribution and habitat
This species is mainly found from southern Ireland and Britain, the southern North Sea to Morocco, and
throughout the Mediterranean. A demersal species found over rocky bottoms down to about 65m (Quero,
1984b), the bull huss has been shown to demonstrate strong site fidelity (Simms et al., 2005).
Biology and Ecology
This medium bodied shark reaches from 130-162cm TL. It is an egg laying species (Quero, 1984b). Little
further information on the species exists.
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Trend
The UK-Irish Sea and Bristol Channel beam trawl survey shows an overall increase since the early 1990s.
Bull huss have been reported consistently by anglers to the ISFC since the 1960s.
Human impacts
This species is sometimes taken as a discarded by-catch in demersal fisheries. Because it is mainly found in
rocky inshore areas, which are avoided by many commercial fishers, it is rarely caught. Its survivability
upon being discarded is very high. Consequently it is not very vulnerable to fisheries.
Management/Conservation
There are no management measures in place for this species.
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Raja microocellata, Montagu, 1818
Small-eyed ray
Irish name: Roc mionsúileach
Status
Ireland: Least concern. NE Atlantic: Near threatened. Global: Least concern.
Justification
Given its restricted and patchy, fragmented geographical distribution and localised abundance, local
populations may potentially be vulnerable to declines caused by over-fishing, habitat degradation and other
anthropogenic disturbance. Catch rates in a scientific trawl survey (1993-2013) of the Bristol Channel have
been stable over the longer time series, although catch rates (all individuals) have declined in the most recent
years therefore it should be closely monitored and reevaluated in the short term.
Range, distribution and habitat
Raja microocellata (small-eyed ray, also known as the painted ray) is a medium-bodied species restricted
primarily to the Atlantic coasts of Northwest Europe (Stehmann and Bürkel 1989) and is most abundant in
bays and other inshore sandy areas (Ellis et al., 2005). Although occasional specimens of R. microocellata are
caught in the southern Irish Sea, the main concentration of this species is in the Bristol Channel, with larger
individuals occurring slightly further off-shore. The species seems to have a fragmented population, possibly
due to the fragmented nature of its favoured inshore, sandy habitat.
In Irish waters it is locally common along the south coast and particularly in Youghal Bay, Ballycotton Bay
and in the Tralee Bay/Castlegregory area where it is targeted by shore anglers. Separate populations appear
to exist off the west coast. The population comprises the inner Celtic Sea and Bristol Channel (ICES, 2014a,b).
Biology and Ecology
Combined data from the North Sea and Celtic Sea ecoregions indicate length-at-maturity (L50) of 68.9cm TL
and 77.9cm TL for males and females, respectively (McCully et al., 2012). The observed length range was 13
80cm TL and 1285cm TL for males and females, respectively (McCully et al., 2012). Fecundity has been
estimated at 54-61 eggs per year, with egg-laying activity peaking between June and September (Ryland and
Ajayi 1984). Size at birth is approximately 10cm TL (Ryland and Ajayi 1984). The feeding habits have been
described for those populations inhabiting Carmarthen Bay (Ajayi 1977, 1982) and the Cove of Bertheaume
in Brittany (Rousset 1987) and it is known that they feed on a variety of crustaceans and teleosts. Juveniles
predate primarily on small shrimps and amphipods, with fishes (e.g. sand eels and dragonets) becoming
more important in the diets of larger individuals. Neonatal R. microocellata are caught infrequently by
fisheries surveys, but are comparatively abundant in beach seine surveys along the sandy shores of the
northern Bristol Channel (Ellis et al., 2005).
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Trend
Survey based indicators showed a stable trend from the mid 1990s to the late 2000s with a more recent
decline of 27% (ICES, 2014). In contrast, recreational catches (based on numbers of specimen skate ≥4.54kg,
all of which are released) have increased in the recent years.
Human impacts
As a coastal and inner shelf species it is a bycatch of trawl and gill net fisheries. It is mainly caught in the
Bristol Channel but other landings come from inshore fisheries on the south, west and northwest coasts. Due
to its restricted distribution, inshore habitats and overall scarcity it may be at risk from overfishing and
habitat disturbance.
Management/Conservation
This species is managed as part of the generic maximum total allowable catch (TAC) for named skate
species, in the waters west of the British Isles.
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Raja montagui Fowler, 1910
Spotted ray
Irish name: Roc mín
Status
Ireland: Least concern. NE Atlantic: Least concern. Global: Least concern.
Justification
Populations of Raja montagui appear to be stable throughout its range despite being commonly landed in
fisheries. Their small body size is likely to mean this species has greater resilience to fishing impacts
compared to larger-bodied skate species. Given these reasons it is classified as “Least Concern”.
Range, distribution and habitat
One of the most common ray species in Irish waters the spotted ray (Raja montagui) is a small-bodied species
with a wide geographic distribution in the Northeast Atlantic and Mediterranean (Stehmann and Bürkel,
1984a). Within the Northeastern Atlantic it tends to occur in inshore waters and shallow shelf seas, in depths
of 8 to 283m (Ellis et al., 2005a), though it is most abundant in waters less than 100m. Juveniles tend to occur
closer inshore on sandy sediments, with adults also common further offshore on sand and coarse sand-
gravel substrates. ICES considers two separate stocks around Ireland. The first is in the Irish and Celtic Seas
and Bristol Channel. The second is west of Scotland, and northwest and west of Ireland (ICES, 2014a,b).
Biology and Ecology
Combined life-history data from the North Sea and Celtic Sea ecoregions indicate length-at-maturity (L50) of
50.9cm TL and 62.5cm TL for males and females, respectively (McCully et al., 2012). The observed length
range was 1067cm TL and 1076cm TL for males and females, respectively (McCully et al., 2012). In the Irish
Sea the length and age at 50% maturity for males and females was reported as 53.7 and 57.4cm TL and 3.4
and 4.1 years, respectively (Gallagher et al., 2005).
Juveniles and egg cases are often abundant in inshore sheltered nursery areas and a high abundance of
juveniles have been recorded in Cardigan Bay, off the east coast of Ireland and around Anglesey (Ellis et al.,
2005). Separate nurseries are likely to occur, based on egg case records, from Dublin to Waterford; Tralee and
Dingle Bays, and some bays in Connacht (Varian et al., 2011).
Trend
The population of spotted ray in the Irish and Celtic Seas has increased over time and is at the highest level
since the indices began in the early 1990s. However there is evidence that the stock is being fished at levels
above those that are sustainable (ICES, 2014). The population off north western and western Ireland has
increased since the early 2000s (ICES, 2014). Recreational angling data (ISFC, unpublished) shows that fewer
specimen fish (≥ 2.29kg) have been recorded since the 1990s which may indicate reductions in numbers of
larger fish.
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Human impacts
As a coastal and inner shelf species it is susceptible to bycatch of trawl and gill net fisheries. Preliminary
studies of catch rates in beam trawl surveys in the English Channel and Irish Sea appeared stable when this
species was last assessed (Ellis et al., 2005b), and IBTS data in the North Sea were also relatively stable (ICES
2006). These catch rates refer to all individuals caught and not just mature fish.
Management/Conservation
This species is managed as part of the generic maximum total allowable catch (TAC) for named skate
species, in the waters west of Ireland and the UK.
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Raja clavata Linnaeus, 1758
Thornback ray
Irish name: Roc garbh
Status
Ireland: Least concern. NE Atlantic: Near threatened. Global: Near threatened.
Justification
Updated population assessments for the northwest Ireland and Irish/Celtic Sea populations show that it is
increasing in abundance in recent years. There is sufficient information to show that it does not warrant any
designation other than “least concern”.
Range, distribution and habitat
This is a medium-bodied ray, found in the coastal waters of the eastern Atlantic, from the Faroe Islands,
Iceland, and Norway to South Africa, in the Mediterranean, the Mid-Atlantic Ridge south from Iceland, and
in the southwestern Indian Ocean (Stehmann and Burkel, 1984a). The species is mainly found on hard
seabed (e.g. gravel and pebble), in areas of intermediate to strong tidal currents at depths of 7192m (Ellis et
al., 2005). Genetic studies have revealed population segregation in R. clavata between the Mediterranean
region, the Azores, and the European shelf waters (Chevolot et al., 2006); however, the regional population
structure of this species remains poorly known. ICES considers two main populations around Ireland, one in
the Irish and Celtic Seas, the other off northwest Ireland (ICES, 2014a,b).
Biology and Ecology
The observed length range was 1089cm TL and 1098cm TL for males and females, respectively (McCully et
al., 2012). Maximum age is reported at 12 years (Ryland and Ajayi, 1984), maturing at age 6 and length 65
71cm (Gallagher et al., 2005), with estimated fecundity from 60140 eggs per year (Holden, 1975). ICES
considers three separate populations around Ireland, NW Ireland/W Scotland, western Ireland and
Irish/Celtic Seas/Bristol Channel. The species moves inshore in spring/summer. The species forms localised
populations along the south and west coasts, with some degree of interchange between them (Fitzmaurice et
al., 2003). Spawning areas include Tralee Bay (Fitzmaurice et al., 2003; Varian et al., 2011), but also Dingle Bay
and the east coast from Dublin to Wexford (Varian et al., 2011). Known nurseries are in inshore areas,
including northern Bristol Channel, Cardigan Bay, Luce Bay, and Solway Firth (Ellis et al., 2005).
Trend
In the Irish and Celtic Sea/Bristol Channel stock, the population size indicator has increased markedly since
the early 2000s. The north-west Ireland/west Scotland stock has increased less markedly over the same
period (ICES, 2014a;b). Specimen catches have declined since the 1990s and no large fish (≥ 8kg) have been
recorded by ISFC since 2007.
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Human impacts
As a coastal and inner shelf species it is a bycatch of trawl and gill net fisheries. It is mainly caught close to
the coasts of the Irish Sea by beam and otter trawlers, and also in the Bristol Channel. Other landings come
from inshore fisheries on the south, west and northwest coasts. As one of the larger species in the skate
complex, it may be targeted in some local, seasonal fisheries. Localised fisheries on the west coast may
disproportionately impact on individual populations especially on the west coast. Small numbers are taken
by recreational anglers in some areas.
Management/Conservation
This species is managed as part of the generic maximum total allowable catch (TAC) for named ray species,
in the waters west of Ireland and the UK.
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Mustelus asterias Cloquet, 1821
Starry smooth-hound
Irish name: Scoirneach ballach
There is longstanding confusion regarding the identification and nomenclature of Mustelus species in the
Northeast Atlantic. The characteristic white spots of Mustelus asterias have long been used to differentiate it
from the common smooth-hound Mustelus mustelus, however the appearance of these spots displays much
intraspecific variability (Farrell, 2010). Based on detailed analyses by Farrell (2010) and Farrell et al. (2009),
there is no evidence of M. mustelus occurring in the northeast Atlantic region north of Portuguese waters. On
this basis, all records of Mustelus spp. in this region should be considered to be M. asterias.
Status
Ireland: Least concern. NE Atlantic: Near threatened. Global: Least concern.
Justification
Abundance trends from the International Bottom Trawl Survey (IBTS) in the Northeast Atlantic appear to be
stable or increasing at the present time. However there has been an increase in reported landings from this
region. The species is assessed as “Least Concern” in this region due to the increasing abundance.
Nonetheless, population trends and catch levels should be carefully monitored.
Range, distribution and habitat
M. asterias is abundant in the Northeast Atlantic Ocean (Irish Sea, North Sea, English Channel, Celtic Sea,
Bristol Channel and Bay of Biscay) and also occurs in the Mediterranean Sea. The southern limit of its
distribution is reported as Mauritania (Compagno, 1984). In Irish waters they are most commonly
encountered off the shallow sandy beaches of the coast of Wicklow and Wexford though there appears to be
a northern increase in their distribution in recent years.
Biology and Ecology
In the NE Atlantic the length and age at 50% maturity for males and females are estimated to be 78cm TL
and 4-5yrs and 87cm TL and 6 yrs, respectively (Farrell et al., 2010b,c). Longevity is estimated to be 13 and
18.3 years for males and females, respectively. Mustelus asterias is an aplacental viviparous species, which
exhibits geographic variation in its reproductive traits. In the Northeast Atlantic ovarian fecundity ranged
from 8 to 27 oocytes and observed uterine fecundity from 6 to 18 embryos (Farrell et al., 2010c). The average
length at birth was 30cm TL. Gestation period was ~ 12 months, followed by a resting period of ~12 months,
resulting in a biennial reproductive cycle. Parturition occurs from April to July