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Global Production of Marine Bivalves. Trends and Challenges


Abstract and Figures

The global production of marine bivalves for human consumption is more than 15 million tonnes per year (average period 2010–2015), which is about 14% of the total marine production in the world. Most of the marine bivalve production (89%) comes from aquaculture and only 11% comes from the wild fishery. Asia, especially China, is by far the largest producer of marine bivalves, accounting for 85% of the world production and responsible for the production growth. In other continents, the production is stabilizing or decreasing (Europe) the last decades. In order to stimulate growth, sustainability (Planet, Profit, People) of the aquaculture activities is a key issue. Environmental (Planet) aspects for sustainable aquaculture include the fishery on seed resources, carrying capacity, invasive species and organic loading. Food safety issues due to environmental contaminants and biotoxines should be minimized to increase the reliability of marine bivalves as a healthy food source and to stimulate market demands. Properly designed monitoring programs are important tools to accomplish sustainable growth of marine bivalve production.
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7© The Author(s) 2019
A. C. Smaal et al. (eds.), Goods and Services of Marine Bivalves,
Chapter 2
Global Production ofMarine Bivalves.
Trends andChallenges
J.W.M.Wijsman, K.Troost, J.Fang, andA.Roncarati
Abstract The global production of marine bivalves for human consumption is
more than 15million tonnes per year (average period 2010–2015), which is about
14% of the total marine production in the world. Most of the marine bivalve pro-
duction (89%) comes from aquaculture and only 11% comes from the wild shery.
Asia, especially China, is by far the largest producer of marine bivalves, account-
ing for 85% of the world production and responsible for the production growth. In
other continents, the production is stabilizing or decreasing (Europe) the last
decades. In order to stimulate growth, sustainability (Planet, Prot, People) of the
aquaculture activities is a key issue. Environmental (Planet) aspects for sustainable
aquaculture include the shery on seed resources, carrying capacity, invasive spe-
cies and organic loading. Food safety issues due to environmental contaminants
and biotoxines should be minimized to increase the reliability of marine bivalves
as a healthy food source and to stimulate market demands. Properly designed mon-
itoring programs are important tools to accomplish sustainable growth of marine
bivalve production.
Abstract in Chinese 在2010~2015年间,海水双壳贝类的年产量超过1500万
J. W. M. Wijsman (*) · K. Troost
Wageningen UR, Wageningen Marine Research, Yerseke, The Netherlands
J. Fang
Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao,
A. Roncarati
URDIS Centre, University of Camerino, San Benedetto del Tronto, AP, Italy
Keywords Bivalves · Oysters · Mussels · China · Europe · Stock assessment ·
关键词 双壳贝类 · 牡蛎 · 贻贝 · 中国 · 欧洲 · 资源评估 ·
2.1 Introduction
Food production has been recognised as one of the most direct provisioning ecosystem
functions of marine environments (Costanza etal. 1997). Food production of marine
ecosystems comprises various types of organisms of which macroalgae, sh, crusta-
ceans and molluscs are the most important. The increase of marine food production has
been recognised as an important solution to full the increasing protein demands of the
growing world population in the future (Naylor etal. 2000). The total global food pro-
duction of marine ecosystems in the period 2009 to 2014 was 104.3million tonnes per
year and consisted of wild capture (80.4million tonnes per year) and marine aquacul-
ture (23.9million tonnes per year) (FAO 2016a, b). Marine bivalves account for about
14% of the global marine production (tonnes) in this period. Most of the marine bivalve
production (89%) comes from aquaculture, with a total economic value of 20.6billion
US$ per year. Only 11% of the marine bivalve production comes from the wild shery.
However, the seed resources that form the basis for aquaculture production are often
shed or collected from natural stocks as well. Due to decreasing seed resources and
environmental issues with the seed shery, more and more of the seed resources for
marine bivalve aquaculture are produced within land-based hatcheries. The direct cap-
ture production of marine bivalves remained relatively constant since the 1970’s
(1.78 million tonnes per year), but the aquaculture production of marine bivalves
increased from 1.18million tonnes per year in the period 1970–1974 to 13.47million
tonnes per year in the period 2010–2015.
The total market value of marine bivalves is about 23 billion US$ per year
(2010–2015), however, the full economic value is much higher due to the economic
benets from secondary products and services (e.g. shucking and packaging houses,
transport, manufacture of prepared products and retail sales) (Schug etal. 2009).
The value of the production in terms of US$ kg1 is depending on the market
demands and the supply of the specic species.
Marine bivalves are appreciated by consumers due to their nutritional benets as
well as their taste. Bivalves are healthy sources of energy and protein, rich in vita-
mins (A and D) and essential minerals (iodine, selenium calcium), low in fat and a
good source of omega-3 fatty acids with well-established health benets (Orban
J. W. M. Wijsman et al.
etal. 2002; Schug et al. 2009; EFSA 2014). Selenium for example is an essential
trace element that is required by the human body for proper functioning of the thy-
roid gland, and may help protect against free radical damage of the tissue. Most of
the dietary human intake of selenium occurs via plants (Brazil nuts) and seafood
(Ariard etal. 1993; Kristan etal. 2015). There is evidence that selenium deciency
may be related to a variety of degenerative diseases (Reilly 1998). However, it is also
known that there is also a narrow concentration window between essentiality and
toxicity of selenium for humans (Kristan etal. 2015). The unavoidable presence of
environmental contaminants, such as mercury and biotoxins in bivalves could also
result in a risk to the health of consumers (Sadhu etal. 2015; Visciano etal. 2016).
Regular monitoring programs, therefore, are essential to prevent food safety issues.
Marine bivalves are also a sustainable type of food production. As herbivores,
they are low in the trophic chain. The trophic position of marine bivalves like mus-
sels, oysters, clams and cockles is 2 (herbivores), while the average trophic position
of the total marine capture shery is 3.1 (Duarte etal. 2009).
In contrast to the intensive sh aquaculture, bivalve aquaculture is an extensive
form of aquaculture while the bivalves feed on algae that occur naturally in the
ecosystem and no additives such as vitamins and antibiotics are added. The produc-
tion relies merely on the natural productivity of marine phytoplankton, either in the
form of living algae or as detritus, transported to the bivalves by water ow e.g.,
currents and tidal exchange. Bivalves can enhance primary production by increased
nutrient recycling (Prins and Smaal 1994). At high stocking densities, however, the
bivalves can result in overgrazing and thereby reduce primary production (Smaal
etal. 2013b; Filgueira etal. 2015). Management by farmers is an important factor
whereas the farmers will try to maximise their prots within their aquaculture sites.
This is done by growing the bivalves at specic locations where the conditions for
growth and survival are maximized (Capelle 2017). Numerous management activi-
ties are possible among which active removal of predators (Calderwood etal. 2016)
and thinning-out and sorting the bivalves to optimise growth efciency and shape.
The moment of harvesting is also decided by the farmers, based on the quality of the
bivalves but also on market prices.
Since aquaculture of marine bivalves takes place in natural environments, it often
results in conicts with other functions such as nature conservation, recreation, eco-
nomic development, etc. Also the shery on marine bivalves might result in con-
icts since natural stocks that are an important food source for sh and birds are
removed from the system (Ens etal. 2004; Ens 2006). Moreover, the shery with
dredges is a bottom disturbing activity that might impact the seaoor integrity. Also
aquaculture often depends on the wild shery for the seed resources (Smaal and
Lucas 2000).
For aquaculture purposes, bivalves and associated organisms are often translo-
cated between sites and ecosystems which has resulted in introduction and spread-
ing of (invasive) exotic species (Minchin and Gollasch 2002; Wolff 2005). Proper
management of bivalve transports are important to reduce environmental impact.
In this paper an overview is given of the trends in global production of marine
bivalves based on FAO data. The production gures for different continents are
2 Global Production ofMarine Bivalves. Trends andChallenges
discussed and compared with each other. As case studies, the trends and developments
in China– by far the largest producer of marine bivalves– and Europe are pre-
sented. In China, the production of marine bivalves is still increasing tremendously
due to the increasing protein demand of the growing population. In Europe, how-
ever, the total production is decreasing the last decades due to various reasons such
as competing claims on space, diseases and carrying capacity issues. For both case
studies an overview is presented of the trends and developments of production,
import and export and legislation. Finally, in this paper, special attention is paid to
stock assessment of marine bivalves since this provides essential information for
sustainable management of natural stocks in order to reduce environmental impact
of the shery on marine bivalves. This is based on a case study of the stock assess-
ment for natural bivalve species in the Wadden Sea, The Netherlands.
2.2 Global Trends
In the FAO Global Fishery and Aquaculture Statistics database a total 79 marine
bivalve species are listed as cultured and 93 species are listed as captured species.
They can be grouped into four major groups: clams, oysters, mussels and cockles.
Clams and oysters are the major species groups that contribute 38% and 33%,
respectively, to the global production. Scallops account for 17% and mussels for
13% of the global production. The global production of marine bivalves is more
than 15million tonnes per year (data FishStat FAO 2010–2015) (Fig. 2.1). More
than 85% of the total marine bivalve production in comes from Asia (Fig.2.2). As a
1970 1973 1976 1979 1982 1985 1988 1991 1994 1997 2000 20032006200920122015
0510 15 20
Production (Mton)
Fig. 2.1 Evolution of the total global production (million tonnes per year) of marine bivalves by
the shery and aquaculture. (Data from FAO FishStat (1970–2015))
J. W. M. Wijsman et al.
1970 1975 1980 1985 1990 1995 2000 2005 2010 2015
0510 15
Production (Mton)
1970 19751980198519901995 2000 2005 2010 2015
0.0 0.5 1.0 1.5
Production (Mton)
1970 1975 1980 1985 1990 1995 2000 2005 2010
0.0 0.5 1.0 1.5
Production (Mton)
1970 1975 1980 1985 1990 1995 2000 2005 2010 2015
0.00 0.05 0.10 0.15
Production (Mton)
197019751980 198519901995 2000 2005 2010 2015
0.0000.002 0.0040.006 0.0080.010
Production (Mton)
Africa Clams
Fig. 2.2 Evolution of the total production (million tonnes per year) of marine bivalves by the shery and aquaculture together for the different continents from
1970 to 2015. Marine bivalves are grouped as clams, mussels, oysters and scallops. (Data from FAO FishStat (1970–2015))
2 Global Production ofMarine Bivalves. Trends andChallenges
result the production in Asia, specically China, largely dominates the patterns and
trends in the world production.
The total production of marine bivalves is the result of a complex interaction
between the market demand and the production capacity of the system. If the market
demand increases, this will be a trigger to increase production. However, the pro-
duction will be limited by the carrying capacity of the system. There are different
types of carrying capacity that could potentially limit the production: physical, pro-
duction, ecological and social carrying capacity (Inglis et al. 2000; Gibbs 2009;
Smaal and Van Duren 2018).
The bivalve production in Asia is increasing on average with 0.42million tonnes
per year since 1990. The majority of the production in Asia comes from clams
(5.4million tonnes in 2015) and oysters (ca 5.1million tonnes in 2015). The pro-
duction of scallops and mussels in 2015 was 2.3 and 1.1million tonnes, respec-
tively. Production in Asia is dominated by the production in China (more than 90%
of the marine bivalve production in Asia). Other marine bivalve producing countries
of importance in Asia are Japan (0.75million tonnes per year), Republic of Korea
(0.4million tonnes per year) and Thailand (0.23million tonnes per year). The major
reason for the increase in marine bivalve production in China is the increased
demand for proteins from the growing population and the increased standard of liv-
ing in China. As a result, social and ecological carrying capacity are no major issues
yet. Spatial and production carrying capacity limitations might be occurring locally
since the availability of suitable productive sites can sometimes be limiting. The
wild shery on marine bivalves in China is not specically documented in the
Fishstat database. Japan is the most important country in Asia in terms of the shery
on marine bivalves, mainly scallops, with an average yearly production of 0.38mil-
lion tonnes in the period 2010–2015. In Indonesia the shery on blood cockles
produce on average about 74thousand tonnes per year (2010–2015).
North and south America is responsible for 9% of the global marine bivalve pro-
duction. Most of the aquaculture production is in Chile (mussels and scallops), Peru
(scallops), the United States (American and Pacic cupped oysters, hard clams) and
Canada (mussels). The wild shery is mainly practiced in the United Stated of
America on scallops, hard clams and surf clams, with a mean total production of
about 510thousand tonnes per year (2010–2015). Also in Canada there is a wild
shery (ca 92thousand tonnes per year) mainly on Atlantic deep-sea scallops. The
total production in north and south America increased from about 1million tonnes
per year in the period 1995–2000 to about 1.3million tonnes per year in the period
2010–2015. This increase is mainly due to the increase of aquaculture production.
Clams used to be the most important species but the production is slightly decreas-
ing since 1988. This is mainly due to a decrease in wild catches of clams in the
United States from about 450thousand tonnes per year in 1985 to a total production
of 250thousand tonnes per year at present (2010–2015). From 2000 the mussel-,
but also the scallop production is increasing in the Americas. The increase in mussel
production is mainly due to an increase in the aquaculture production in Chile with
a tenfold increase in this century from 23thousand tonnes in 2000 to a current
J. W. M. Wijsman et al.
production of about 244thousand tonnes per year (2010–2015). In the United States
of America, the wild shery on oysters decreased from 200thousand tonnes in the
early 70’s of the last century to a production of about 59thousand tonnes per year
in the period 2010–2015. The aquaculture production of eastern oysters increased
from about 106thousand tonnes per year in the period 1995–1999 to a total produc-
tion of 142thousand tonnes per year at present (2010–2015).
In Europe, responsible for 5.5% of the world production of marine bivalves, the
production has decreased since 1998. This decrease is mainly due to a decrease in
mussel production by aquaculture activities from about 600thousand tonnes per
year in 1998 to about 465thousand tonnes per year in the period 2010 to 2015. The
production of bottom culture mussels in the Netherlands is responsible for part of
this reduction since the production in the Netherlands decreased from 113thousand
tonnes in 1998 to 46thousand tonnes per year in the period 2010–2015. The produc-
tion is limited by a reduction in physical space due to competing claims with nature
conservation and occasional recruitment failures. Production of oysters, clams and
scallops in Europe is much lower than the mussel production. The oyster production
decreased from 150thousand tonnes in 1998 to about 94thousand tonnes per year
(average 2010–2015), with the largest production in France (ca 78thousand tonnes
per year). In Ireland, however, the production of oysters is increasing. Almost 25%
of the marine bivalve production in Europe, yearly about 205thousand tonnes per
year, comes from the shery. The highest capture production is in the UK (scallops
and cockles), Denmark (blue mussels), France (scallops) and Italy (venus clams).
The production in Africa and Oceania is less than 1% of the world production. In
Oceania mussels, mainly produced in New Zealand, are by far the most important
bivalve species, with a total production of about 94thousand tonnes per year (2010–
2015). In Australia there is additionally some production of at and cupped oysters.
The shery on marine bivalves is very limited in Oceania. In Africa, there is some
sheries (ca 2 thousand tonnes per year) on carpet shells and cupped oysters in
Tunisia and Senegal. Mussels are cultured in South Africa with a total production of
800tonnes per year. The low production in Africa is low due to the limited market
demands. The local community has no tradition in consuming bivalves, since it is
often difcult to keep the healthy sanitary conditions.
2.3 China
2.3.1 Aquaculture Production inChina
Aquaculture production of China is the highest in the world (61.5million tonnes
in 2015). The total output of marine aquaculture in China in 2015 was 29.5mil-
lion tonnes and consists of marine bivalve production of 12.4million tonnes,
macroalgae production of 13.8million tonnes, sh production around 1.6 million
2 Global Production ofMarine Bivalves. Trends andChallenges
tonnes1 and other organisms (e.g. molluscs, crustaceans, echinoderms) about
1.7million tonnes (FAO FishStat). Marine bivalves represented 42% of the total
mariculture production in China in 2015. The production increased from an aver-
age of 51thousand tonnes per year in 1950–1959 to 335thousand tonnes per year
in 1975–1979, 7.3million tonnes per year in 2000–2004 to 12.4million tonnes in
2015 (Fig.2.3). Besides marine bivalves, macroalgae are also responsible for the
enormous growth in marine aquaculture production in China since 1990 (Fig.2.3).
The major shellsh cultured in China include 8 categories (oysters, clams, scal-
lops, mussels, razor clams, cockles, sea snails and abalones) and 48 species (Tang
etal. 2016), among which oysters, clams and scallops yield more than 1million
tonnes annually, and the production of mussels and razor clams fall between 0.5
to 1million tonnes each year.
2.3.2 Trends andDevelopments
Bivalve aquaculture has a long history in China, the record of oyster farming can be
traced back to 2400years ago, in the ancient book “Pisciculture” written by Fan Li,
a famous politician, strategist, Taoist and Economist. In the 1950s and 1960s of the
twentieth century, the main species of Chinese bivalve culture were oyster and mus-
sel. The major farming methods were tideland cultivation and natural sea area nurs-
ing (Liu 1959).
1 In the China Fishery statistical yearbook a production of 1.3million tonnes sh is reported for
1950 1954 1958 1962 1966 1970 1974 1978 1982 1986 1990 1994 1998 2002 2006 2010 2014
0510 15 20 25
Production (Mton)
Fig. 2.3 Changes in mariculture production (million tonnes per year) in China. (Data from FAO
FishStat (1950–2015))
J. W. M. Wijsman et al.
In the beginning of 1970s, the technologies for seed production of mussel in
hatcheries and natural sea seed collection made great progress, which promoted the
rapid development of mussel culture industry. In 1977, the national mussel farming
area was more than 2000ha, and the annual production exceeded 60,000 tonnes,
about 200times and 75times respectively compared to those in 1970. In late 1970s,
the success in articial breeding of cockles Tegillarca granosa, and Sinonovacula
constricta, clams Ruditapes philippinarum and Cyclina sinensis laid the foundation
for development of the large-scale culture of these species. In the early 1980s, the
breakthrough of articial breeding in hatcheries and natural sea seed collection of
Chlamys farreri, had led to the rapidly development of the scallop culture at indus-
trial level. Particularly, the introduction of bay scallop Argopecten irradians from
Atlantic coast in 1982 brought a prosperous stage for Chinese scallop aquaculture
New Eco-farming aquaculture modes such as integrated aquaculture of shellsh
and seaweed in shallow-sea, and pond farming of shrimp-shellsh, has contributed
greatly to the development of modern Chinese marine aquaculture. In recent years,
China has carried out research on varieties of shellsh selective breeding. Until to
2015, 18 new varieties of shellsh were determined by genetic and selective breed-
ing, including oysters, scallops, hard clams, abalone, pearl oyster and manila clam,
which had been certicated by the national new variety committee in China.
Shellsh farming methods now include maritime longline culture (northern China)
and raft culture (southern China), mud at farming, bottom sow farming, and pond
culture. Integrated aquaculture of shellsh-sh, shellsh-shrimp and shellsh-
seaweed has become the new trend for mariculture development in China.
From 2005 to 2014, the bivalve culture production maintained an overall growth.
During these 10years, production of scallops, clams, oysters and mussels increased
by 80.4%, 40.8%, and 30.0% and 19.3%, respectively. Shellsh prices showed over-
all rise during the last 10years with inter-annual uctuations. In 2015, the domestic
shellsh wholesale price data shows that, the average price of live oysters was
increased from 0.87US$/kg to 0.98US$/kg, an increase of approximately 12.1%.
The average price of live razor clam, from the same period last year, increased from
3.99US$/kg to 4.09US$/kg, an increase of slightly 1.9%. Scallop adductor muscle
average price, reduced by 7.8% from 3.50US$/kg to 3.23 US$/kg in the same
period last year; the average price of fresh clams decreased from 1.16US$/kg to
1.13US$/kg compare to the same period last year, down by 2.6%.
2.3.3 Import andExport
In 2014, scallops, oysters and mussels were the major imported and exported mol-
luscs, with the net import and export being 33.3thousand tonnes and 32.1thousand
tonnes, respectively. The scallops, oysters and mussels import were 29.0thousand
tonnes, 2.6thousand tonnes and 1.6thousand tonnes, respectively, and the export of
these 3 bivalve species were 29.2 thousand tonnes, 1.3 thousand tonnes and
2 Global Production ofMarine Bivalves. Trends andChallenges
1.5thousand tonnes for each. The annual import and export volume were 135.7 and
453.0million US dollars respectively. From 2008 to 2014, China imported shellsh
mainly from the United States, Japan, North Korea, South Korea, France and New
Zealand, and the shellsh exported went to United States, South Korea, Hong Kong,
Macao and Australia. In 2014, the Chinese imports of oysters, scallops and mussels
were mainly from France, Japan and North Korea, while the export of these species
went to Hong Kong, the United States and South Korea. Data from China Customs
show that from January to October 2015, China’s shellsh export amount and rev-
enue was 219thousand tonnes (1.87% increase compared to the same period in
2014) and 1.38billion US$ (1.11% decrease compared to the same period in 2014).
2.3.4 Legislation
The impact of marine bivalve culture to the environment is expected to be relatively
small. This is mainly due to the ltering capacity, removing particles from the water
column. Moreover, no additives (food, antibiotics, etc.) are added to the system.
Nevertheless, there are many laws and regulations related to mariculture in China
(Table2.1). Besides the state-level management, protection and zoning regulations,
there are also provincial level laws and regulations on natural resources exploitation
and development. For instance, “Marine Functional Zoning of Shandong Province”
has clearly claried the scope and area that can be applied for aquaculture. Since
2007, the Ministry of Agriculture Fisheries Bureau executed the functional zoning
for shellsh mariculture in Guangdong Province and 11 other areas. Reference from
the relevant provisions of the EU, the Ministry announced the “Requirements for
shellsh mariculture regional zoning”, which dened the 3 categories of shellsh
products according to the content of Escherichia coli (MPN/100g) in meat and juice
in the shellsh. For category one, the Escherichia coli content should be no more
Table 2.1 Relevant legislation concerning marine shellsh production in China
“Law on the Administration of Sea Area Use of the People’s Republic of China”, 2002
“Law on Marine Environmental Protection of the People’s Republic of China”, 2000
“Fisheries Law of the People’s Republic of China”
“Standard for Seawater Quality of the People’s Republic of China” (GB3097-1997), 1997
“National Marine Functional Zoning (2011–2020)”, 2012
“Regulations of Marine Environmental Protection of Shandong Province”, 2004
“Regulations on the Administration of Sea Area Use in Shandong Province” 2004
“Marine Functional Zoning of Shandong Province”, 2012
“Requirements for Shellsh Mariculture Regional Zoning”
“Law of Quality and Safety of Agricultural Products of People’s Republic of China”
“Provisions on the Administration of Aquaculture Quality”
“Provisional Regulations on Supervision and Management of Shellsh Production Environment”
“Provisions on the Hygiene Management of Exporting Shellsh”
J. W. M. Wijsman et al.
than 230 E. coli/100g, bivalves can be put into the market directly; the second
category refers to the Escherichia coli content can be greater than 230 E. coli/100g
and no more than 4600 E. coli/100g, which can be put into the market directly without
raw food permit. Bivalves with Escherichia coli content more than 4600 E. coli/100g
and no more than 46,000 E. coli/100g are in the third category, which need to be
kept depurated until reached the standard in the second category before sales.
2.4 Europe
2.4.1 Aquaculture Production inEurope
In Europe, aquaculture production has remained relatively constant in the last years.
In 2015, the total output of European aquaculture was 3.0million tonnes, of which
the majority (2.4million tonnes) was marine production (FAO FishStat). The marine
aquaculture production was represented almost exclusively by sh production
(about 1.8 million tonnes) and bivalve production (about 598 thousand tonnes)
(FEAP 2016; FAO 2017). Culture of other marine organisms like macroalgae and
crustaceans is negligible in Europe (Fig.2.4). The most important species (freshwa-
ter and marine) reared in Europe in 2015 are Atlantic salmon (1.6million tonnes per
year), mussels (497thousand tonnes per year), rainbow trout (290thousand tonnes
per year), common carp (154 thousand tonnes per year), Pacic cupped oyster
(89thousand tonnes per year), gilthead sea bream (79thousand tonnes per year) and
European sea bass (68 thousand tonnes per year) (FAO 2017). Among the EU
1950 1954 1958 1962 1966 1970 1974 1978 1982 1986 1990 1994 1998 2002 2006 2010 2014
0.51.0 1.5 2.0
Fig. 2.4 Changes in mariculture production (million tonnes per year) in Europe. Macroalgae and
others are hardly visible. (Data from FAO FishStat (1950–2015))
2 Global Production ofMarine Bivalves. Trends andChallenges
Member States, the largest producers of marine aquaculture products are Norway
(1.4million tonnes, mainly Atlantic salmon), Spain (271thousand tonnes per year),
United Kingdom (196thousand tonnes per year), France (161thousand tonnes per
year) and Greece (103thousand tonnes per year). With regard to the aquaculture of
marine bivalves in the different countries, Mediterranean mussels accounted for
83.0% of the marine aquaculture in Spain whereas in France, the largest volumes
were produced by Pacic cupped oyster (46.6%), blue mussel (37.9%) and
Mediterranean mussel (8.8%). The growth of marine Aquaculture production in
Europe is mainly caused by the increase in sh culture (Atlantic salmon) since
1985–1990 (Fig.2.4). The production of marine bivalves by European aquaculture
is decreasing from an average production of 661thousand tonnes per year in the
period 1995–1999 to an average of 560thousand tonnes per year in the period
2.4.2 Trends andDevelopments
In Europe, bivalve aquaculture has ancient origins, both for oysters and mussels.
Images on archaeological ndings (pots) date back the oyster farm to Roman times,
between the second and rst century BC.In Italy, in the lakes Lucrino and Fusaro
(Campania Region) at oysters were reared for the Roman nobles consumption. In
Spain, in the fourth century BC, the natives used to leave bivalve molluscs in large
deposits denominated ‘concheiros’; the rst ndings of bivalve culture were discov-
ered near to the Roman villages in the rst century A.D.In France, the mussel culture
was practised in the intertidal zone since the thirteenth century using wooden stakes
called “bouchots”. This technique spread widely along the French Atlantic coastline
over the nineteenth century, while Northern European countries (the Netherlands,
Ireland and the United Kingdom) developed bottom culture plots where juveniles
were spread over the plots in shallow water, generally in bays or in sheltered areas on
the ground. The French “bouchot” system, currently still in use, consists of ropes
carrying young mussels placed on vertical poles and then, as the mussels grow, they
move onto the pole where they will grow until they reach their commercial size. In
the Middle Ages, oyster culture was widespread in the Sea of Taranto (Puglia Region,
Italy). Under the kingdom of Ferdinand IV of Bourbon, around 1764, oysters contin-
ued to be farmed in the Fusaro Lake. In the sixteenth century, in Spain, people com-
ing from Portugal began to gather mussels, clams, and cockles in the ria of Arosa
(NW Spain). At the turn of the nineteenth century, at oyster culture was well devel-
oped especially in the Bay of Arcachon (France), reaching 15–20,000tonnes per
year between 1908 and 1912. In 1979 the disease caused by the exotic parasite
Bonamia ostreae broke down the productions (Buestel etal. 2009). Between 1971
and 1973, after the depletion of the Portuguese oyster (Crassostrea angulata) deci-
mated by several successive diseases, several hundred tonnes of Crassostrea gigas
were imported from Canada and the species became established and an abundant
spat was settled in Marennes-Oleron (France). In the Mediterranean, at oysters
J. W. M. Wijsman et al.
were cultured until 1950 when high mortalities strongly reduced productions due to
a disease caused by the protozoan, Marteilia refringens.
In the Netherlands, due to numerous conicts in the nineteenth century among
shermen for the open access to sh blue mussels (Mytilus edulis) and at oysters
(Ostrea edulis) in the delta region in the southwest of the Netherlands, the rearing
system changed and mussel and oyster shermen could rent exclusive access rights
to plots in the sea. This plot system facilitated the beginning of bottom culture of
blue mussel and at oyster because only the person who rented the plot draw the
benets from the harvest. In 1952, plots to grow mussels could also be leased in the
shallow Wadden Sea in the north of the Netherlands and this led to the development
of a second region where blue mussel was cultured.
Mussels became important in Spain when farmers started culturing them in the
beginning of the twentieth century. In longline systems, mussels are cultured on
ropes that remain suspended in the water from a long line composed of buoys,
whereas oysters are introduced in trays or “poches”, attached to the rope. The long
lines can be semi-submerged, submerged or buoyant depending on the farming
environment. “Bateas mussel rafts” are largely employed in Spain. Rafts are com-
posed of a solid structure from which the mussels hang in the water. In the bottom
mussels system, predominantly used in the Netherlands, Germany, Ireland and the
UK, large at boats equipped with 2 to 4 dredges, sh juvenile mussels from natural
beds which then are relayed in sheltered areas for further growth until they reach the
commercial size. Currently, the Pacic cupped oyster is the most widely reared
oyster species in Europe thanks to its fast growth, adaptability to different settings
and improving breeding lines in the hatchery. Since 2008, high mortalities have
been recorded in many European countries due to herpesviruses affecting larvae,
spats and juveniles of cupped oysters highlighting the emergence of a global prob-
lem involving not only the European countries, but also New Zealand and Australia.
Concerning clams (Ruditapes decussatus, Tapes philippinarum), the farming began
in the 1980s, when harvesting wild stocks by hand or by dredging was discouraged
in order to protect resources. Currently, clam farming depends mainly on natural
recruitment and reproduction in hatchery. Spat is grown in nursery areas or tanks
and seeded in shallow areas managed by shermen’s cooperatives.
2.4.3 Import andExport
Data from EUMOFA Report 2016, based on the elaboration of Eurostat data, show
that in 2015, EU imports of mussels totalled 200,000tonnes, the lowest volume in
the past 6years, 10,000tonnes less than the average import volume from 2010–
2014. France, the EU’s largest market, recorded stable imports in 2015 when com-
pared with the 2010–2014 average, while Italy, the second largest importer,
demonstrated a remarkable increase in import volumes (+28%) compared with the
average volume imported in the 2010–2014 period. Portugal recorded a signicant
growth of the import as well. Otherwise, import to all other EU markets declined
2 Global Production ofMarine Bivalves. Trends andChallenges
rather sharply: the Netherlands (49%), the UK and Germany (19% each), and
Spain and Belgium (10% each). This reduction in imports can be explained by the
economic crisis as well as the increase in prices (average price from US$ 10.30 per
kg in 2010 to US$ 15.40 per kg in 2015). European bivalve export amounted at
20,000tonnes (+9% respect to 2014) and 172million US$ (+24% respect to 2014).
EU self-sufciency for this commodity fell to 61%. The EU consumption of mus-
sels registered a slightly uctuating trend from 2005 to 2014, with the apparent
consumption moving from 1.36kg per capita in 2005 to 1.27kg per capita in 2014.
Chile and New Zealand are the two main suppliers of mussels to Europe, providing
the market with frozen and conserved products. Intra-EU trade is well developed
with a value around half the total value of the EU supply. There are major trade
ows from Spain, the Netherlands and Denmark (wild mussels in the case of
Denmark) to Belgium, France and Italy. The European consumption of scallop in
2014 was almost at the same level as in 2005. Its peak of 0.63kg per capita was
registered in 2010, and a 4% decrease was recorded between 2013 and 2014, due to
the reduction in catches in the United Kingdom and France of 11% and 29%,
respectively. Since 2005, consumption of clam has remained stable at an average of
0.35kg per capita (EUFOMA 2016).
2.4.4 Legislation, Environmental Issues
In the European Union, in 1979, the “Shellsh Water Directive 79/923/EEC” con-
cerning the quality of shellsh waters to protect populations from the harmful con-
sequences resulting from the discharge of polluting substances into the sea, was
enacted. This legislation has laid down and updated ofcial controls for monitoring
bivalve production and relaying areas (Table2.2). The authorities, based on faecal
indicator organisms (E. coli), determine the classication of a production area and
the treatment required in growing areas during the production cycle and for the end-
product. The classication marks three classes: Class A (230 E. coli/100g), mol-
luscs can be harvested for direct human consumption; Class B (90% of samples
must be 4600 E. coli/100g; all samples must be less than 46,000 E. coli/100g),
molluscs can be sold for human consumption after purication in an approved plant,
or after re-laying in an approved Class A re-laying area, or after an EC-approved
heat treatment process; Class C (46,000 E. coli/100g), molluscs can be sold for
human consumption only after re-laying for at least 2months in an approved re-
laying area followed, where necessary, by treatment in a purication centre, or after
an EC-approved heat treatment process. The European Food Safety Authority Panel
on Biological Hazards has reviewed the hazards and has also determined the need
to restrict shellsh harvesting from areas contaminated with faecal pollution.
Molluscs must not be subject to production or collected in prohibited areas. In 2010,
the EU Commission Regulation was enacted to identify the presence of OsHV-1
μvar associated with the massive mortality in oysters in order to reduce the spread
J. W. M. Wijsman et al.
of the virus to uninfected regions. According to the regulation, disease control mea-
sures must be implemented. This includes the establishment of containment areas
and the restriction of movement from these areas if OsHV-1 μvar is identied.
2.5 Stock Assessment
Culture of some marine bivalve species is dependent on shery on wild stocks. Seed
is for instance collected using spat collectors, or shed in the natural environment.
Culture of such species (e.g. blue mussels (Mytilus edulis) and Pacic cupped oys-
ters Crassostrea gigas) is therefore dependent on the availability of natural stocks.
The natural stocks of most bivalve species show large uctuations from year to year,
depending on the success of natural spatfall. Moreover, the spatial heterogeneity is
high because many species occur locally within dense beds. Stock assessments are
of key importance for sheries regulation and management and provide essential
information for impact assessment studies.
We illustrate the role of stock assessment with the case study of blue mussels in
the Dutch part of the Wadden Sea. The Netherlands is, after Spain and France the
third producer of mussels in Europe, with a total production of about 63million kg
per year (1990–2015). In contrast to the suspended culture in Spain, in the
Netherlands the mussels are mainly cultured on-bottom at designated culture plots
Table 2.2 Relevant legislation concerning marine shellsh production in Europe
“Regulation (EC) NO 178 of the European Parliament and of the Council laying down the
general principles and requirements of food law, establishing the European Food Safety
Authority and laying down procedures in matters of food safety”, 2002
“Commission Decision establishing special health checks for the harvesting and processing of
certain bivalve molluscs with a level of amnesic shellsh poison (ASP) exceeding the limit laid
down by Council Directive 91/492/EEC”, 2002
“Regulation (EC) No 852 of the European Parliament and of the Council on the hygiene of
foodstuffs”, 2004
“Regulation (EC) No 853 of the European Parliament and of the Council laying down specic
hygiene rules for on the hygiene of foodstuffs”, 2004
“Regulation (EC) No 854 of the European Parliament and of the Council laying down specic
rules for the organisation of ofcial controls on products of animal origin intended for human
consumption”, 2004
“Commission Regulation (EC) No 2073 on microbiological criteria for foodstuffs”, 2005
“Commission Regulation (EC) No 2074 laying down implementing measures for certain
products under Regulation (EC) No 853/2004 of the European Parliament and of the Council
and for the organisation of ofcial controls under Regulation (EC) No 854/2004 of the European
Parliament and of the Council and Regulation (EC) No 882/2004 of the European Parliament
and of the Council, derogating from Regulation (EC) No 852/2004 of the European Parliament
and of the Council and amending Regulations (EC) No 853/2004 and (EC) No 854/2004”, 2005
“Commission Regulation (EC) No 1664 amending Regulation (EC) No 2074/2005 as regards
implementing measures for certain products of animal origin intended for human consumption
and repealing certain implementing measures”, 2006
2 Global Production ofMarine Bivalves. Trends andChallenges
that are located in the Wadden Sea and in the Oosterschelde. The mussels are
cultured by about 50 companies, operating 60 vessels (Capelle 2017). The mussel
culture depends largely on natural seed resources. Mussel seed is dredged from
naturally occurring subtidal mussel beds in the Wadden Sea in Autumn and Spring.
From there they are translocated to the culture plots in the Wadden Sea and the
Oosterschelde where they are kept for 1–3years until they reach consumption size.
The mussels are harvested mainly in Summer and Autumn and sold at the auction in
Yerseke. From there they are processed and distributed over Europe (mainly
Belgium, France, the Netherlands, Germany).
Since 1992 the natural mussel stock in the subtidal areas of the Wadden Sea is
assessed annually from two different surveys. A quantitative survey in early Spring
and a qualitative survey in Autumn (Van Stralen etal. 2016, 2017). In Autumn, the
mussel seed shery is exclusively allowed in subtidal areas that are designated as
being unstable due to starsh (Asterias rubens) predation and exposure to unfavour-
able hydrodynamic conditions. In other words, in areas where the seed beds are
likely to disappear before, or in the course of, the following winter. Designation of
areas as stable or instable was made based on survey results since 1992 and expert
judgement of shermen and sheries inspectors (Smaal etal. 2014). To determine
the amount of mussels to be shed during the autumn sheries in these instable
areas, an estimate of the total stock of seed mussels is made in late summer or early
autumn. A qualitative assessment of starsh abundance gives insight in the likeli-
hood of particular beds disappearing before winter, which is used in the sheries
plan to identify beds to be shed rst. In early spring a second stock assessment is
carried out, with the primary purpose to prepare the sheries permit for the spring
sheries, and with the secondary purpose to be able to assess effects of changes in
the sheries policy and management. Where the autumn assessment is a qualitative
survey, the spring assessment is set up as a quantitative survey in which not only
mussels but all species of bivalves, starsh and crabs are recorded. This dataset
gives insight in distribution patterns of mussels and other bivalves, shery impacts,
as well as the main benthic predators, and is therefore of key importance in studies
on effects of sheries and changes in sheries and nature policy (Smaal etal. 2013a).
The autumn assessment is carried out with a mussel dredge. Historical informa-
tion as well as observations by sheries inspectors and shermen is used to deter-
mine the areas with a high encounter probability. Using the mussel dredge, operated
by a commercial mussel sheries vessel, the bed contours and kilograms per square
meter are estimated. The total seed mussel stock, as well as the exploitable stock
size in areas open to the shery in autumn is estimated based on the dredge data and
expert judgement.
The spring assessment is carried out with a suction dredge. For stations with a
water depth over 10 meters a towed bottom dredge is used. Both sampling gears sh
along a track with known length (ca 150m) and surface area. The sampling loca-
tions are distributed along a stratied regular sampling grid where the distance
between stations is smaller in areas with a high encounter probability. The encoun-
ter probability is estimated based on the autumn survey, the autumn shery
(gps- data of the shing vessels), historical information and observations by sheries
J. W. M. Wijsman et al.
inspectors and shermen. During the Spring survey (March–April) 400–600 locations
are sampled within a period of 3–4weeks. The samples are sieved over a mesh of
5mm, and all species of shellsh, crabs and starsh are counted and weighed per
station (total wet weight). The total stock is calculated as the sum of all stations:
biomass (wet weight) per square meter per station multiplied by the surface area the
sampling station is representative for (which is determined by the stratum).
The amount of wild sublittoral mussels in the western Wadden Sea (Spring sur-
vey) is presented in Fig.2.5 (bars). The lines indicate the total amount that has been
harvested for grow-out on mussel culture plots in spring and autumn. As can be seen
from this gure, in some years more seed has been shed than found during the
spring survey. This is due to a new recruitment during the summer months, after the
spring survey and spring sheries and before autumn sheries of the same year.
Due to competing claims with shellsh-eating birds, one of the nature conserva-
tion goals in the Wadden Sea, a transition from bottom sheries to seed collection
using suspended seed collectors (SMCs) has taken place within the mussel culture
since 2010. According to an agreement between the mussel producers’ organiza-
tion, NGO’s and the Dutch government, a gradually increasing portion of the stable
areas are closed for shing. The area available for SMCs is proportionally increased.
The total harvest of the SMCs in the Wadden Sea increased from 1.3Mkg in 2009
to 15.2Mkg in 2016 (Capelle and Van Stralen 2017). The SMCs resulted in a more
1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 2012 2014 2016
Gross amount (Mkg)
020406080 100
Fig. 2.5 Total wild stock of mussels in the sublitoral part of the western Wadden Sea (spring sur-
vey) and the total gross amount seed shed (Spring and Autumn) of that year. To calculate the
Gross amount 40% debris and associated fauna is assumed for mussel seed and 25% for adult
mussels. It is also assumed that the seed will gain 20% in weight between survey and shery
2 Global Production ofMarine Bivalves. Trends andChallenges
stable supply of mussel seed for the mussel farmers, making them less depending on
the uctuations in natural spatfall on the bottom. Data from the stock assessments
are an essential tool for the (evaluation of the) management decisions.
2.6 Conclusions
Food production is an important provisioning ecosystem function of marine
bivalves. The global production is growing, although this growth is mainly caused
by the increase in aquaculture production in Asia, in particular China. The bivalve
farming has already become a considerable scale industry in China and has pro-
vided high quality proteins for humans. The production in North and South America,
however, is stabilizing since 2000 and the production in Europe is decreasing.
It is expected that the global production of marine bivalves, particularly in Asia,
will continue to grow in the future in order to full part of the protein demand of the
growing world population, especially since bivalves are a sustainable form of pro-
tein production. The expected growth in production of marine bivalves will come
mainly from an increase in aquaculture production since it can be foreseen that the
production from wild catches is relatively limited and will probably only decrease
in the future. Sustainability (People, Prot, Planet) is an important factor for a fur-
ther increase in marine bivalve production. Bivalve aquaculture is depending to a
large extent, if not completely, on natural ecosystems, which are in many cases
nature conservation areas. Removal of seed resources and microalgae as food source
for the bivalves can, in some areas, result in competing claims with other ecosystem
Stock assessments are of primary importance in determining sustainable seed
supply. The case study Wadden Sea shows that annual monitoring of bivalve stocks,
resulting in long-term time series, is important for the year-to-year management of
bivalve stocks since it gives insight in the population dynamics as well as potential
ecological impacts of sheries and aquaculture targeted on marine bivalves. This
can also be applied to other regions where aquaculture is depending on wild stocks.
With increasing emphasis on sustainability, the balance between aquaculture
development and ecology/environment has become a new requirement and chal-
lenge in both research and commercial aspects. The development of a sustainable
bivalve aquaculture will promote employment in the coastal shing zones support-
ing diversication in areas linked to changes in the sheries sector. It could be of
great socio-economic importance because it would allow the recovery and enhance-
ment of traditional activities related to the region. New opportunities for local man-
agement of commercial shing may open up to guarantee the characteristics of the
product being of great interest to the consumer.
Acknowledgements Dr. Yuze Mao from YSFRI is acknowledged for providing valuable
information on aquaculture production in China. The authors are grateful to the referees
Dr. J.Grant and Dr. R.Filgueira for their valuable comments on the manuscript.
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J. W. M. Wijsman et al.
... Mussel aquaculture has grown rapidly in the past few decades to form an important global industry, with production exceeding 1.6 million tonnes in 2018 and accounting for around 13% of global marine bivalve production (Wijsman et al., 2019). However, mussel aquaculture still relies heavily upon irregular supplies of recently settled juveniles (also known as 'spat'), which are harvested from a range of wild sources before being transported to farm sites and seeded onto farming substrata to initiate the production cycle (Walter & Liebezeit, 2003;Filgueira et al., 2007;Alfaro et al., 2010;Kamermans & Capelle, 2019). ...
... Mussels are one of the most widely farmed aquaculture species, with 2 million tonnes produced each year (Wijsman et al., 2019), worth an estimated $2.7 billion USD (Kamermans & Capelle, 2019). Nonetheless, the early stages of mussel aquaculture can be extremely inefficient, with high losses of the seed mussels (also referred to as 'spat') of being placed onto mussel farms (South et al., 2019). ...
... The effect of bivalves on aquatic ecosystems is important because they are often engineer species (Vaughn & Hoellein, 2018) offering habitat to a large diversity of species (Wijsman et al., 2018). ...
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Cancer is an understudied but important process in wildlife that is predicted to have a significant effect on the evolution of metazoan species due to negative effects on host fitness. However, gaining understanding of the impact of cancer on species and ecosystems is currently relatively slow as the development of both animal models in which cancer can be induced and experiments that can be performed in an ecological setting are required. Invertebrates, because they are widely available and relatively easy to manipulate, are promising animal models. In this review we examine how tumours can be induced in invertebrates to use them as experimental models to study the effects of cancer on the ecology and evolution of species. We identified four main groups of invertebrates (planarian, bivalves, hydra and drosophila) in which such inductions are performed. We then reviewed the types and effectiveness of the methods employed to induce tumours in those groups. Cancer alters the phenotype of the host. We review how experiments using invertebrate models can be used to investigate the impact of cancer on tumour‐bearing individuals for their movement, reproduction, feeding behaviours, social interactions, holobiont and predation risk. We provide recommendations to facilitate the development of new invertebrate models. We also highlight a series of key questions on the ecology and evolution of cancer that could be answered with the use of invertebrate models.
... Global aquaculture production in 2018 was, overall, 82.1 million tonnes of food fish, of which 17.7 million tonnes was contributed by molluscs alone (FAO 2020). During the period from 2009 to 2014, 14% of the world-wide marine production came from bivalves, of which 89% was directly from aquaculture, i.e. mustering an annual of 20.6 billion US dollars (Wijsman et al. 2019). These statistics pinpoint the significance of sustainable production of bivalve mariculture globally. ...
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Despite the attempts that have started since the 1960s, not even a single cell line of marine molluscs is available. Considering the vast contribution of marine bivalve aquaculture to the world economy, the prevailing viral threats, and the dismaying lack of advancements in molluscan virology, the requirement of a marine molluscan cell line is indispensable. This synthetic review discusses the obstacles in developing a marine molluscan cell line concerning the choice of species, the selection of tissue and decontamination, and cell culture media, with emphasis given on the current decade 2010–2020. Detailed accounts on the experiments on the virus cultivation in vitro and molluscan cell immortalization, with a brief note on the history and applications of the molluscan cell culture, are elucidated to give a holistic picture of the current status and future trends in molluscan cell line development.
... Positive environmental impacts, good nutritional value, and significant health benefits have fuelled an expansion of bivalve aquaculture industry, which reached a yield of $17 MT in 2018 ($35 billion USD; Food and Agriculture Organization, 2020). Spain is the largest producer of bivalves in Europe (287,000 t in 2018; Food and Agriculture Organization, 2020), with 94% of production devoted to cultures of the Mediterranean mussel Mytilus galloprovincialis (271,000 t year À1 ; Wijsman et al., 2019). Sustainable mussel farming is driving an increased interest in offshore aquaculture, which can support a faster and healthier growth of farmed species (Barillé et al., 2020;Kirchhoff et al., 2011), and is considered to reduce nutrient loadings into coastal environments (e.g., Bristow et al., 2008;Vezzulli et al., 2008). ...
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Global expansion of bivalve aquaculture can drive sustainable protein production. Inland culture of mussel spat can play an important role in supporting extensive mussel farming. Nursery culture of bivalves is, however, dependent on nutritious, cost‐efficient, and more reliable diets for spat. The aim of this study was to assess the impact of dietary alternatives to commercial algal feeds (Shellfish Diet 1800) on the survival and growth of Mytilus galloprovincialis spat, widely farmed in Europe. Spat (6.8 ± 1.1 mm) were supplied with different diets for 6 weeks: commercial microalgal diet (A), microencapsulated feeds containing a 1:1 blend of the macroalga Undaria pinnatifida and the microalga Schizochytrium (BioBullets; BB), or commercial microalgae and BioBullets combined (ABB). Unsupplemented spat showed no growth and little change in body condition (CI). Spat fed microcapsules grew at comparable rates, and body condition rose at higher levels (shell growth rates: 8.5 ± 3.7 μm day−1; ΔCI: 6.1 ± 1.1%) relative to those fed commercial microalgae (8.5 ± 5.7 μm day−1; ΔCI: 3.3 ± 0.8%). Supplementing microencapsulated feeds with the commercial microalgal diet did not significantly improve growth performances (9.3 ± 2.3 μm day−1; ΔCI: 4.7 ± 1.4%) relative to mussels fed microcapsules alone. Microencapsulated feeds for M. galloprovincialis spat production can significantly reduce nursery costs compared with commercial feeds or cultured microalgae. By sourcing encapsulated algae from aquaculture side streams, microencapsulated feeds can further promote circular economies.
... Large-scale seed production of the Atlantic sea scallop (Placopecten magellanicus) is also underdeveloped, in part because of this species' slow development (>40-day larval period) and juvenile mobility (Fitzgerald, 2021). This has caused farmers who are interested in growing non-traditional species, or even established species with limited hatchery-raised supply, to be dependent on highly unreliable wild seed collections; this constrains the productivity of individual growers and in turn, the industry as a whole (Wijsman et al., 2019;Hassan et al., 2021). ...
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The Atlantic surfclam (Spisula solidissima) is a promising candidate for species diversification in the United States Northeast because it is native, grows rapidly, and is relatively recognizable to the public. However, gaps in the surfclam husbandry literature have left aquaculture practitioners without a complete understanding of how to best cultivate this species on commercial scales. In particular, relatively few studies have examined which culture conditions are necessary for rearing juvenile surfclams during the nursery phase. To fill this gap, controlled experiments were conducted to evaluate the efficacy of various gear types that are commonly used to rear other juvenile bivalve species. Specifically, growth and survival of early juvenile surfclams (0.4–2.7 mm) were compared when reared in different gear combinations, including downwellers, upwellers, and bell siphon systems. Similarly, growth and survival of late juvenile surfclams (1.1–18.0 mm) were compared when reared in upwellers and shallow raceways, with and without sand. Sediment accumulation, a proxy for culture cleanliness and system maintenance, was also monitored during the late nursery experiment. Results indicate that multiple rearing methods can effectively produce commercial-scale quantities of surfclams, but flow rate, food availability, and temperature are important factors that can limit gear efficiency. All early nursery gear systems performed similarly, while the late nursery upweller system performed significantly better than both types of shallow raceway systems. This study reinforces the feasibility of surfclams as a culture species that aligns well with the Northeast’s established shellfish farming framework.
... Global bivalve production has significantly grown (~1 -18 million t) over the past 70 years (FOA, 2020), with approximately 90% of the produce coming from aquaculture (Wijsman et al., 2019). In this context, the occurrence of harmful algal blooms (HABs) represents a considerable and ongoing issue for the shellfish industry, as some species of microalgae can produce marine biotoxins which can bioaccumulate in bivalves (after consuming algae from the water column), enter the food web, and cause sicknesses and/or death of higher trophic organisms, including humans. ...
Diarrhetic shellfish toxins produced by certain species of the marine dinoflagellate Dinophysis can accumulate in shellfish in high concentrations, representing a significant food safety issue worldwide. This risk is routinely managed by monitoring programs in shellfish producing areas, however the methods used to detect these harmful marine microbes are not usually automated nor conducted onsite, and are often expensive and require specialized expertise. Here we designed a quantitative real-time polymerase chain reaction (qPCR) assay based on the ITS-5.8S ribosomal region of Dinophysis spp. and evaluated its specificity, efficiency, and sensitivity to detect species belonging to this genus. We designed and tested twenty sets of primers pairs using three species of Dinophysis - D. caudata, D. fortii and D. acuminata. We optimized a qPCR assay using the primer pair that sufficiently amplified each of the target species (Dacu_11F/Dacu_11R), and tested this assay for cross-reactivity with other dinoflagellates and diatoms in the laboratory (11 species) and in silico 8 species (15 strains) of Dinophysis, 3 species of Ornithocercus and 2 species of Phalacroma. The qPCR assay returned efficiencies of 92.4% for D. caudata, 91.3% for D fortii, and 91.5% for D. acuminata, while showing no cross-reactivity with other phytoplankton taxa. Finally, we applied this assay to a D. acuminata bloom which occurred in an oyster producing estuary in south eastern Australia, and compared cell numbers inferred by qPCR to those determined by microscopy counts (max abund. ∼6.3 × 10³ and 5.3 × 10³ cells L⁻¹ respectively). Novel molecular tools such as qPCR have the potential to be used on-farm, be automated, and provide an early warning for the management of harmful algal blooms.
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(This article belongs to the Section Fishery Economics, Policy, and Management) The vast expanse of China’s land surface results in the country’s environment varying from region to region. Environmental changes impact on China’s industries, markets, and trade, indirectly affecting not only the country’s economy but also the people who depend on aquaculture resources. Regional differentiation leads to an imbalance that severely affects social fairness and equity, which becomes a key factor limiting the sustainable development of the economy and society. Analysis and assessment of the changes in environmental factors affecting aquaculture production and fisherfolk’s income in 31 regions of China between 2010 and 2020 aim to provide a reference for regional differentiation in the economic development of aquaculture in the different regions in China, representing an essential step towards achieving the coordinated development of rural regional areas. This study’s assessment and analysis procedures adopted the principal component analysis method. The findings suggest that regional differences in Chinese fisherfolk’s income and the environmental factors affecting China’s aquaculture production are veritable. There have been subtle changes in regional differentiation over a decade. It is necessary to implement contextualized environmental management measures, concessionary taxation, and additional subsidies to address the different characteristics of China’s different regions for the future development of environmental management and narrowing the income gap, to address both the income disparities in Chinese fisherfolk’s income and environmental factors affecting Chinese aquaculture production, to achieve the harmonious development of rural regional areas.
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Marine pathogens present serious challenges to aquaculture, fisheries productivity, and marine conservation requiring novel solutions to identify, control, and mitigate their effects. Several ecological habitats, such as mangroves and wetlands can recycle waste and serve as aquatic filtration systems. While nutrient cycling and other ecosystem services of these habitats have been well-studied, their potential to remove pathogens and mechanisms of filtration remain largely unstudied. Here, we review how mangroves, shellfish beds, seagrasses, and constructed wetlands can reduce pathogen pressure in coastal ecosystems. Mangroves may inhibit bacterial growth through phytochemicals in their leaves and remove viruses through desalination in their roots. Some bivalves remove pathogens by excreting pathogens through their pseudofeces and others concentrate pathogens within their tissues. Seagrasses slow flow rates, increase sedimentation rates and may reduce pathogens through allelopathy. Constructed wetlands decrease pathogens through a combination of mechanical, biological, and chemical filtration mechanisms. Protecting and restoring coastal ecosystems is key to maintaining pathogen filtration capacity, benefiting conservation efforts of threatened host populations, and mitigating large disease outbreaks.
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To predict the response of the European flat oyster (Ostrea edulis) and Pacific cupped oyster (Crassostrea gigas/Magallana gigas) populations to environmental changes, it is key to understand their life history traits. The Dynamic Energy Budget (DEB) theory is a mechanistic framework that enables the quantification of the bioenergetics of development, growth and reproduction from fertilization to death across different life stages. This study estimates the DEB parameters for the European flat oyster, based on a comprehensive dataset, while DEB parameters for the Pacific cupped oyster were extracted from the literature. The DEB parameters for both species were validated using growth rates from laboratory experiments at several constant temperatures and food levels as well as with collected aquaculture data from the Limfjorden, Denmark, and the German Bight. DEB parameters and the Arrhenius temperature parameters were compared to get insight in the life history traits of both species. It is expected that increasing water temperatures due to climate change will be beneficial for both species. Lower assimilation rates and high energy allocation to soma explain O. edulis’ slow growth and low reproductive output. Crassostrea gigas’ high assimilation rate, low investment in soma and extremely low reserve mobility explains the species’ fast growth, high tolerance to starvation and high reproductive output. Hence, the reproductive strategies of both species are considerably different. Flat oysters are especially susceptible to unfavourable environmental conditions during the brooding period, while Pacific oysters’ large investment in reproduction make it well adapted to highly diverse environments. Based on the life history traits, aquaculture and restoration of O. edulis should be executed in environments with suitable and stable conditions.
Marine bivalves account for roughly 14% of aquaculture production worldwide and ca. 33% of this production is represented by oysters. A number of disease-causing agents of oysters have the potential to create economic loss to shellfish farmers. Disease outbreaks due to Vibrio coralliiyticus are considered to be a major problem in the hatchery production of bivalve larvae and juveniles (spat). An effective management strategy in preventing disease in bivalves is to produce genetically resistant families. Since 1996, researchers from Oregon State University's Molluscan Broodstock Program (MBP) have bred and selected families of Pacific oysters (Crassostrea gigas) with greater growth, yield, and survival at harvest compared to wild C. gigas; however, there has been no experimental assessment of the MBP families' resistance to Vibrio coralliiyticus. The progeny of 89 MBP families were challenged with V. coralliiyticus in a microplate assay. Larval survival was assessed over a seven-day period with independent time points using image analysis, which reconstructed the contents of each well. The narrow sense (h²) heritability of disease resistance for MBP oyster larvae to V. coralliiyticus was determined with a linear mixed effects model, known as the animal model. After accounting for the influence of fixed and random effects (time point, animal, and plate well), the estimate of heritability of survival (h²) was detectable on both the latent (0.535–0.541) and observed scales (0.113–0.114). The low heritability estimates on the observed scale suggest that enhancement of MBP's oyster larvae's resistance to V. coralliiyticus through selective breeding is expected to take multiple generations. Estimating the heritability of C. gigas to V. coralliiyticus may have been complicated by the life stage examined, the dynamics of V. coralliiyticus infection, and uncontrolled environmental factors in the well plate assays.
Technical Report
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We report the development, use and harvest statistics on Spat Mussel Collectors (SMCs) in the Netherlands for 2016. Total harvest in 2016 for Oosterschelde and Wadden Sea was 18.06 Mkg.
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Mussel bottom culture is an extensive type of aquaculture; it depends on natural resources for feed, seed and space. It consists of the translocation of seed from natural beds to designed culture areas, where mussel farmers try to improve production efficiency. Production efficiency is measured by the relative biomass production (RBP) expressed as units of biomass harvested from one unit of biomass seeded, it increases with mussel growth and decreases with mussel mortality. Mussel bottom culture makes use of nature and also depends on nature. Cultured mussels are subject to similar environmental factors that influence growth and mortality on natural mussel beds, with additional effects of anthropogenic factors. In this thesis we focus on dynamics of mussel beds and the impact and effectivity of culture activities on mussel production yield. The major objectives are stated as: (1) to better understand the population dynamics of subtidal mussel populations, (2) to analyze what factors determine production efficiency in mussel bottom culture and how this can be improved. On natural mussel beds mussels organise in patterns that enhance food delivery and resilience of the bed. On culture plots mussels are seeded in concentric seeding patterns. Seeding techniques concentrate mussels locally within the culture plot area, resulting in high local mussel densities; this increases competition and limits the spatial re-organisation of mussels in the bed. Consequently, seeding on culture plots is followed by a large size and density dependent seeding loss that ranges from about 40% for seed from fishery to 69% for smaller SMC seed. This loss was the major factor in determining the maximum RBP. Losses in the grow-out stage were substantially lower, a subsequent density dependent loss was found for smaller mussels (<30 mm), and a non-density dependent loss for larger mussels (>30 mm). Shore crab predation is an important factor contributing to the higher losses at seeding. The effect of shore crab predation on mussel biomass production is higher than expected from previous studies. In an experiment on an intertidal culture plot in the Oosterschelde (NL), we observed that shore crab predation peaks directly after seeding and accounted for 33% of the total losses within five weeks after seeding. Spatial patterns in the survival rates of natural mussel beds in the Wadden Sea show better seed survival in areas with intermediate salinity (mean annual salinity 17.5-22.5 mg l-1). This suggests that mussel survival is negatively related to sea star distribution, which is largely controlled by salinity. Natural beds that escape predation are found at lower salinities and mussels on these beds showed low growth rates, also because of a lower food quality in these areas. Mussel culture strongly affects the population dynamics of the subtidal mussel population, through relaying of mussels from natural mussel beds to culture plots. Culture plots are located in more saline regions of the Wadden Sea (mean annual salinity 25.8 mg l-1), compared to natural mussel beds. This activity increased mussel growth and survival because food quality on culture plots is high and predation is prevented. As a result, average biomass production is higher on culture plots than on natural mussel beds and this difference increases over time. A more efficient seed use on the available area, that can be obtained by reducing seeding losses will increase RBP, maximum biomass production and increases maximum profit. Our results suggest that this can be achieved by seeding homogeneously in low densities.
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Harmful algal blooms are natural phenomena caused by the massive growth of phytoplankton that may contain highly toxic chemicals, the so-called marine biotoxins causing illness and even death to both aquatic organisms and humans. Their occurrence has been increased in frequency and severity, suggesting a worldwide public health risk. Marine biotoxins can accumulate in bivalve molluscs and regulatory limits have been set for some classes according to European Union (EU) legislation. These compounds can be distinguished in water- and fat-soluble molecules. The first group involves those of Paralytic Shellfish Poisoning and Amnesic Shellfish Poisoning, whereas the toxins soluble in fat can cause Diarrhoeic Shellfish Poisoning and Neurotoxic Shellfish Poisoning. Due to the lack of long-term toxicity studies, establishing tolerable daily intakes for any of these marine biotoxins was not possible, but an acute reference dose can be considered more appropriate, because these molecules show an acute toxicity. Dietary exposure assessment is linked both to the levels of marine biotoxins present in bivalve molluscs and the portion that could be eaten by consumers. Symptoms may vary from a severe gastrointestinal intoxication with diarrhoea, nausea, vomiting and abdominal cramps to neurological disorders such as ataxia, dizziness, partial paralysis and respiratory distress. The official method for the detection of marine biotoxins is the mouse bioassay (MBA) showing some limits due to ethical restrictions and insufficient specificity. For this reason, the liquid chromatography-mass spectrometry method has replaced MBA as the reference technique. However, the monitoring of algal blooms producing marine biotoxins should be regularly assessed in order to obtain more reliable, accurate estimates of bloom toxicity and their potential impacts.
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The opportunities for the spread of exotics increase with the greater movement of goods and people around the world. In early times human exploratory activities were responsible for some selected species being moved as food or for cultural reasons but also inadvertently carried. As trading links and colonisation of distant lands developed a more regular transport evolved. As a result organisms spread to areas beyond their normal range, the ways in which this is done is the subject of this chapter.
The carrying capacity concept for bivalve aquaculture is used to assess production potential of culture areas, and to address possible effects of the culture for the environment and for other users. Production potential is depending on physical and production carrying capacity of the ecosystem, while ecological and social carrying capacity determine to what extent the production capacity can be realized. According to current definitions, the ecological carrying capacity is the stocking or farm density of the exploited population above which unacceptable environmental impacts become apparent, and the social capacity is the level of farm development above which unacceptable social impacts are manifested. It can be disputed to what extent social and ecological capacities differ, as unacceptable impacts are social constructs. In the approach of carrying capacity, focus is often on avoiding adverse impacts of bivalve aquaculture. However, bivalve populations also have positive impacts on the ecosystem, such as stimulation of primary production through filtration and nutrient regeneration. These ecosystem services deserve more attention in proper estimation of carrying capacity and therefore we focus on both positive and negative feedbacks by the bivalves on the ecosystem. We review tools that are available to quantify carrying capacity. This varies from simple indices to complex models. We present case studies of the use of clearance and grazing ratio’s as simple carrying capacity indices. Applications depend on specific management questions in the respective areas, the availability of data and the type of decisions that need to be made. For making decisions on bivalve aquaculture, standards, threshold values or levels of acceptable change (LAC) are used. The FAO framework for aquaculture is formulated as The Ecosystem Approach to Aquaculture. It implies stakeholder involvement, and a carrying capacity management where commercial stocks attribute in a balanced way to production, ecological and social goals. Simulation models are being developed as tools to predict the integrated effect of various levels of bivalve aquaculture for specific management goals, such as improved ecosystem resilience. In practice, bivalve aquaculture management is confronted with different competing stocks of cultured, wild, restoration and invasive origin. Scenario models have been reviewed that are used for finding the balance between maximizing production capacity and optimizing ecological carrying capacity in areas with bivalve aquaculture.
Dit rapport gaat over de effecten van mosselzaadvisserij in de westelijke Waddenzee op de natuurwaarden beneden laagwater: het sublitoraal. In de periode 2006 – 2012 is hiernaar onderzoek gedaan in opdracht van de overheid en de schelpdiersector. Het onderzoek is opgezet omdat onvoldoende bekend was welke gevolgen de mosselzaadvisserij zou kunnen hebben voor de natuurwaarden. Aangezien de Waddenzee een beschermd natuurgebied is, is er een vergunning nodig om te mogen vissen. Hiervoor moet door middel van een passende beoordeling worden aangetoond dat de visserij geen als significant te beoordelen negatieve effecten heeft op de realisatie van de instandhoudingsdoelstellingen voor de habitattypen en soorten waarvoor het gebied waarin de visserij plaatsvindt, is aangewezen. De profielen voor de habitattypen en soorten omschrijven wat onder die natuurwaarden moet worden verstaan. De vraagstelling van dit onderzoek komt er op neer na te gaan in hoeverre er effecten zijn van mosselzaadvisserij op de geformuleerde instandhoudingsdoelstelling voor habitattype 1110A, permanent overstroomde zandbanken (subtype ‘getijdengebied’). Omdat bij de aanvang van het onderzoek door diverse overheidsinstanties nog volop werd gewerkt aan het definiëren van de instandhoudingsdoelstellingen, is het onderzoek breder van opzet, en zijn meerdere variabelen in het onderzoek meegenomen waarmee natuurwaarden kunnen worden beschreven.
The starfish, Asterias rubens, preys on mussels (Mytilus edulis), which are relaid during benthic cultivation processes. Starfish mops, a modified dredge used to remove starfish from mussel cultivation beds, are used in several fisheries today but few studies have attempted to quantify the effectiveness of this method in removing starfish. This study tested the effectiveness of starfish mopping to reduce starfish numbers on mussel beds in Belfast Lough, Northern Ireland. Video surveys to determine starfish densities on mussel beds were conducted between October 2013 and December 2014 using a GoPro™ camera attached to starfish mops. This allowed us to firstly test whether starfish density varied among mussel beds and to investigate how fluctuations in starfish numbers may vary in relationship to starfish ecology. We then estimated the efficiency of mops at removing starfish from mussel beds by comparing densities of starfish on beds, as determined using video footage, with densities removed by mops. Starfish abundance was similar among different mussel beds during this study. The efficiency of mops at removing estimated starfish aggregations varied among mussel beds (4–78%) and the mean reduction in starfish abundance was 27% (± SE 3.2). The effectiveness of mops at reducing starfish abundance was shown to decline as the initial density of starfish on mussel beds increased. It can be recommended that the exact deployment technique of mops on mussel beds should vary depending on the density of starfish locally. The area of mussel bed covered by mops during a tow, for example, should be less when starfish densities are high, to maintain efficiencies throughout the full length of tows and to optimise the removal of starfish from mussel beds. This strategy, by reducing abundance of a major predator, could assist in reducing losses in the mussel cultivation industry.
Methyl mercury (MeHg) concentrations were determined in edible fish and shellfish available in local markets in Dunedin, New Zealand. While most of the fish species were sourced in Dunedin, some specimens of fish were also collected from waters off Picton, around Stewart Island and also off-shore of the South Island in the Puysegur and Subantarctic regions. The concentrations of MeHg were analysed in 25 different fish species and shellfish (103 muscle tissue samples). Total mercury (HgT) levels were also analysed in a few (n=12) selected fish samples. Most of the Hg was in the form of MeHg (≥96%). Higher MeHg concentrations were found in fish at higher trophic levels, particularly in predatory fish species such as ling, school shark, spiny dogfish and albacore tuna. Concentrations of MeHg in all samples ranged from 0.002 to 2.515μgMeHg/g.