Atlantic cod: Difference between revisions
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| status = VU | | status = VU | ||
| status_system = IUCN2.3 | | status_system = IUCN2.3 | ||
| status_ref = <ref name="iucn status 1996">{{cite iucn |author=Sobel, J. |date=1996 |title=''Gadus morhua'' |volume=1996 | | | status_ref = <ref name="iucn status 1996">{{cite iucn |author=Sobel, J. |date=1996 |title=''Gadus morhua'' |volume=1996 |article-number=e.T8784A12931575 |doi=10.2305/IUCN.UK.1996.RLTS.T8784A12931575.en |access-date=19 November 2021}}</ref> | ||
| image = Atlantic Cod, Atlantischer Kabeljau (Gadus morhua).jpg | | image = Atlantic Cod, Atlantischer Kabeljau (Gadus morhua).jpg | ||
| image2 = Atlantic cod.jpg | | image2 = Atlantic cod.jpg | ||
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Colouring is brown or green, with spots on the [[Dorsum (biology)|dorsal]] side, shading to silver ventrally. A stripe along its [[lateral line]] (used to detect vibrations)<ref name="Bleckmann 13–25">{{Cite journal|last1=Bleckmann|first1=Horst|last2=Zelick|first2=Randy|date=2009-03-01|title=Lateral line system of fish|journal=Integrative Zoology|volume=4|issue=1|pages=13–25|doi=10.1111/j.1749-4877.2008.00131.x|issn=1749-4877|pmid=21392273|doi-access=free}}</ref> is clearly visible. Its [[habitat (ecology)|habitat]] ranges from the coastal shoreline down to {{convert|300|m|ft|-2|abbr=on}} along the [[continental shelf]]. | Colouring is brown or green, with spots on the [[Dorsum (biology)|dorsal]] side, shading to silver ventrally. A stripe along its [[lateral line]] (used to detect vibrations)<ref name="Bleckmann 13–25">{{Cite journal|last1=Bleckmann|first1=Horst|last2=Zelick|first2=Randy|date=2009-03-01|title=Lateral line system of fish|journal=Integrative Zoology|volume=4|issue=1|pages=13–25|doi=10.1111/j.1749-4877.2008.00131.x|issn=1749-4877|pmid=21392273|doi-access=free}}</ref> is clearly visible. Its [[habitat (ecology)|habitat]] ranges from the coastal shoreline down to {{convert|300|m|ft|-2|abbr=on}} along the [[continental shelf]]. | ||
Atlantic cod is one of the most heavily fished species. Atlantic cod was fished for a thousand years by north European fishers who followed it across the North Atlantic Ocean to North America. It supported the US and | Atlantic cod is one of the most heavily fished species. Atlantic cod was fished for a thousand years by north European fishers who followed it across the North Atlantic Ocean to North America. It supported the US and Canadian fishing economy until 1992, when the Canadian Government implemented [[Collapse of the Atlantic northwest cod fishery|a ban on fishing cod]]. | ||
Several cod stocks collapsed in the 1990s (decline of more than 95% of maximum historical [[biomass]]) and have failed to fully recover even with the cessation of fishing.<ref name="Frank" /> This absence of the [[apex predator]] has led to a [[trophic cascade]] in many areas.<ref name="Frank" /> Many other cod stocks remain at risk. The Atlantic cod is labelled vulnerable on the [[IUCN Red List of Threatened Species]], per a 1996 assessment that the IUCN notes needs updating.<ref name="iucn status 1996" /> A 2013 assessment covering only Europe shows the Atlantic cod has rebounded in Europe, and it has been relabelled least concern.<ref name=IUCN>{{cite iucn |author=Cook, R. |author2=Fernandes, P. |author3=Florin, A. |author4=Lorance, P. |author5=Nedreaas, K. |year=2015 |title=''Gadus morhua'' (Europe assessment) |volume=2015 | | Several cod stocks collapsed in the 1990s (decline of more than 95% of maximum historical [[biomass]]) and have failed to fully recover even with the cessation of fishing.<ref name="Frank" /> This absence of the [[apex predator]] has led to a [[trophic cascade]] in many areas.<ref name="Frank" /> Many other cod stocks remain at risk. The Atlantic cod is labelled vulnerable on the [[IUCN Red List of Threatened Species]], per a 1996 assessment that the IUCN notes needs updating.<ref name="iucn status 1996" /> A 2013 assessment covering only Europe shows the Atlantic cod has rebounded in Europe, and it has been relabelled least concern.<ref name=IUCN>{{cite iucn |author=Cook, R. |author2=Fernandes, P. |author3=Florin, A. |author4=Lorance, P. |author5=Nedreaas, K. |year=2015 |title=''Gadus morhua'' (Europe assessment) |volume=2015 |article-number=e.T8784A45097319 |doi= |access-date=10 July 2024}}</ref> | ||
Dry cod may be prepared as unsalted [[stockfish]],<ref name="milwell">''Oxford English Dictionary'', 3rd ed. "milwell, ''n.''" Oxford University Press (Oxford), 2002.</ref><ref name="stockfish">''Oxford English Dictionary'', 1st ed. "stock-fish| 'stockfish, ''n.''" Oxford University Press (Oxford), 1917.</ref> and as [[curing (food preservation)|cured]] [[salt cod]] or [[clipfish]].{{Refn|group=n|Former names for salted cod include ''cured cod'',<ref name=greencod/> ''ling'',<ref name=greencod/><ref name=ling>''Oxford English Dictionary'', 1st ed. "ling, ''n. | Dry cod may be prepared as unsalted [[stockfish]],<ref name="milwell">''Oxford English Dictionary'', 3rd ed. "milwell, ''n.''" Oxford University Press (Oxford), 2002.</ref><ref name="stockfish">''Oxford English Dictionary'', 1st ed. "stock-fish| 'stockfish, ''n.''" Oxford University Press (Oxford), 1917.</ref> and as [[curing (food preservation)|cured]] [[salt cod]] or [[clipfish]].{{Refn|group=n|Former names for salted cod include ''cured cod'',<ref name=greencod/> ''ling'',<ref name=greencod/><ref name=ling>''Oxford English Dictionary'', 1st ed. "ling, ''n.<sup>1</sup>''" Oxford University Press (Oxford), 1903.</ref><ref name=haberdine/> and ''haberdine''.<ref name=seaport/><ref name=haberdine>''Oxford English Dictionary'', 1st ed. "† haberdine, ''n.''" Oxford University Press (Oxford), 1898.</ref> Freshly-salted cod was known as ''green cod'', ''white cod'', ''corefish'',<ref name=greencod>''Oxford English Dictionary'', 3rd ed. "green cod, ''n.<sup>1</sup>''" Oxford University Press (Oxford), 2011.</ref> ''coursfish'',<ref name=stockfish/> and green fish or greenfish.<ref name=greenfish/> "Green cod" may also refer to the [[saithe]] (''Pollachius virens''), [[Pollachius pollachius|pollack]] (''P. pollachius''), or uncommonly to the [[lingcod]] (''O. elongatus'').<ref name=greenfish/> "Ling" now more often refers to [[Ling (disambiguation)|other fish]], particularly the [[common ling]] (''Molva molva'').<ref name=ling/>}} | ||
==Taxonomy== | ==Taxonomy== | ||
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</gallery> | </gallery> | ||
Atlantic cod will attain sexual maturity between ages two and eight with this varying between different populations and has also varied over time with a population.<ref name=":1" /><ref name=":2" /> Their [[gonad]]s take several months to develop and most populations will spawn from January to May.<ref>{{Cite journal |last=ICES |date=2005 |title=Spawning and life history information for North Atlantic cod stocks |url=https://ices-library.figshare.com/articles/_/18624242 |doi=10.17895/ICES.PUB.5478}}</ref><ref>{{Cite journal |last1=Kjesbu |first1=Olav Sigurd |last2=Righton |first2=David |last3=Krüger-Johnsen |first3=Maria |last4=Thorsen |first4=Anders |last5=Michalsen |first5=Kathrine |last6=Fonn |first6=Merete |last7=Witthames |first7=Peter R. |date=April 2010 |editor-last=Marshall |editor-first=C. Tara |title=Thermal dynamics of ovarian maturation in Atlantic cod (Gadus morhua) |url=http://www.nrcresearchpress.com/doi/10.1139/F10-011 |journal=Canadian Journal of Fisheries and Aquatic Sciences |language=en |volume=67 |issue=4 |pages=605–625 |doi=10.1139/F10-011 |bibcode=2010CJFAS..67..605K |hdl=11250/108908 |issn=0706-652X|hdl-access=free }}</ref> For many populations, the spawning grounds are located in a different area | Atlantic cod will attain sexual maturity between ages two and eight with this varying between different populations and has also varied over time with a population.<ref name=":1" /><ref name=":2" /> Their [[gonad]]s take several months to develop and most populations will spawn from January to May.<ref>{{Cite journal |last=ICES |date=2005 |title=Spawning and life history information for North Atlantic cod stocks |url=https://ices-library.figshare.com/articles/_/18624242 |doi=10.17895/ICES.PUB.5478}}</ref><ref>{{Cite journal |last1=Kjesbu |first1=Olav Sigurd |last2=Righton |first2=David |last3=Krüger-Johnsen |first3=Maria |last4=Thorsen |first4=Anders |last5=Michalsen |first5=Kathrine |last6=Fonn |first6=Merete |last7=Witthames |first7=Peter R. |date=April 2010 |editor-last=Marshall |editor-first=C. Tara |title=Thermal dynamics of ovarian maturation in Atlantic cod (Gadus morhua) |url=http://www.nrcresearchpress.com/doi/10.1139/F10-011 |journal=Canadian Journal of Fisheries and Aquatic Sciences |language=en |volume=67 |issue=4 |pages=605–625 |doi=10.1139/F10-011 |bibcode=2010CJFAS..67..605K |hdl=11250/108908 |issn=0706-652X|hdl-access=free }}</ref> For many populations, the spawning grounds are located in a different area from the feeding grounds so require the fish to migrate in order to spawn. On the spawning area, males and females will form large schools. Based on behavioral observations of cod, the cod mating system has been likened to a [[lekking]] system, which is characterized by males aggregating and establishing dominance hierarchies, at which point females may visit and choose a spawning partner based on status and sexual characteristics.<ref name="Ponomarenko 1965 349–354" /> Evidence suggests male sound production and other sexually selected characteristics allow female cod to actively choose a spawning partner. Males also exhibit aggressive interactions for access to females.<ref name="Hutchings">{{cite journal |last=Hutchings |first=Jeffrey A |author2=Bishop, Todd D |author3=McGregor-Shaw, Carolyn R |date=1 January 1999 |title=Spawning behaviour of Atlantic cod: evidence of mate competition and mate choice in a broadcast spawner |journal=Canadian Journal of Fisheries and Aquatic Sciences |volume=56 |issue=1 |pages=97–104 |doi=10.1139/f98-216}}</ref> | ||
Atlantic cod are batch spawners, in which females will spawn approximately 5–20 batches of eggs over a period of time with 2–4 days between the release of each batch.<ref>{{Cite journal |last1=Kjesbu |first1=O S |last2=Solemdal |first2=P |last3=Bratland |first3=P |last4=Fonn |first4=M |date=1996-03-01 |title=Variation in annual egg production in individual captive Atlantic cod ( Gadus morhua ) |url=http://www.nrcresearchpress.com/doi/10.1139/f95-215 |journal=Canadian Journal of Fisheries and Aquatic Sciences |language=en |volume=53 |issue=3 |pages=610–620 |doi=10.1139/f95-215 |bibcode=1996CJFAS..53..610K |hdl=11250/109284 |issn=0706-652X|url-access=subscription }}</ref><ref>{{Cite journal |last=Kjesbu |first=O. S. |date=February 1989 |title=The spawning activity of cod, Gadus morhua L. |url=https://onlinelibrary.wiley.com/doi/10.1111/j.1095-8649.1989.tb03302.x |journal=Journal of Fish Biology |language=en |volume=34 |issue=2 |pages=195–206 |doi=10.1111/j.1095-8649.1989.tb03302.x |bibcode=1989JFBio..34..195K |issn=0022-1112|url-access=subscription }}</ref> Each female will spawn between 2 hundred thousand and 15 million eggs, with larger females spawning more eggs.<ref>{{Cite journal |last1=Skjæraasen |first1=Jon Egil |last2=Nilsen |first2=Trygve |last3=Kjesbu |first3=Olav S |date=2006-02-01 |title=Timing and determination of potential fecundity in Atlantic cod (''Gadus morhua'') | Atlantic cod are batch spawners, in which females will spawn approximately 5–20 batches of eggs over a period of time with 2–4 days between the release of each batch.<ref>{{Cite journal |last1=Kjesbu |first1=O S |last2=Solemdal |first2=P |last3=Bratland |first3=P |last4=Fonn |first4=M |date=1996-03-01 |title=Variation in annual egg production in individual captive Atlantic cod ( Gadus morhua ) |url=http://www.nrcresearchpress.com/doi/10.1139/f95-215 |journal=Canadian Journal of Fisheries and Aquatic Sciences |language=en |volume=53 |issue=3 |pages=610–620 |doi=10.1139/f95-215 |bibcode=1996CJFAS..53..610K |hdl=11250/109284 |issn=0706-652X|url-access=subscription }}</ref><ref>{{Cite journal |last=Kjesbu |first=O. S. |date=February 1989 |title=The spawning activity of cod, Gadus morhua L. |url=https://onlinelibrary.wiley.com/doi/10.1111/j.1095-8649.1989.tb03302.x |journal=Journal of Fish Biology |language=en |volume=34 |issue=2 |pages=195–206 |doi=10.1111/j.1095-8649.1989.tb03302.x |bibcode=1989JFBio..34..195K |issn=0022-1112|url-access=subscription }}</ref> Each female will spawn between 2 hundred thousand and 15 million eggs, with larger females spawning more eggs.<ref>{{Cite journal |last1=Skjæraasen |first1=Jon Egil |last2=Nilsen |first2=Trygve |last3=Kjesbu |first3=Olav S |date=2006-02-01 |title=Timing and determination of potential fecundity in Atlantic cod (''Gadus morhua'') |journal=Canadian Journal of Fisheries and Aquatic Sciences |volume=63 |issue=2 |pages=310–320 |doi=10.1139/f05-218 |bibcode=2006CJFAS..63..310S |issn=0706-652X}}</ref> Females release gametes in a ventral mount, and males then [[fertilization|fertilize]] the released eggs. The eggs and newly hatched larvae float freely in the water and will drift with the current, with some populations relying upon the current to transport the larvae to nursery areas.<ref>{{Cite book|title=The DK Nature Encyclopedia|last=Burnie|first=David|publisher=DK Publishing, Inc|year=1998|isbn=0-7894-3411-3|location=New York|pages=[https://archive.org/details/dknatureencyclop0000unse/page/189 189]|url=https://archive.org/details/dknatureencyclop0000unse/page/189}}</ref> | ||
== Parasites == | == Parasites == | ||
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{{See also|Cod fisheries}} | {{See also|Cod fisheries}} | ||
[[File:Atlantic cod, capture production, million tonnes, 1950-2022.svg|thumb|Global capture production of Atlantic cod (''Gadus morhua'') in million tonnes from 1950 to 2022, as reported by the [[Food and Agriculture Organization|FAO]]<ref>{{Cite web |title=Fisheries and Aquaculture - Global Production |url=https://www.fao.org/fishery/en/collection/global_production?lang=en |access-date=2024-05-06 |website=Food and Agriculture Organization of the United Nations (FAO)}}</ref>]] | [[File:Atlantic cod, capture production, million tonnes, 1950-2022.svg|thumb|Global capture production of Atlantic cod (''Gadus morhua'') in million tonnes from 1950 to 2022, as reported by the [[Food and Agriculture Organization|FAO]]<ref>{{Cite web |title=Fisheries and Aquaculture - Global Production |url=https://www.fao.org/fishery/en/collection/global_production?lang=en |access-date=2024-05-06 |website=Food and Agriculture Organization of the United Nations (FAO)}}</ref>]] | ||
Atlantic cod has been targeted by humans for food for thousands of years,<ref>{{Cite journal |last1=Ólafsdóttir |first1=Guðbjörg Ásta |last2=Pétursdóttir |first2=Gróa |last3=Bárðarson |first3=Hlynur |last4=Edvardsson |first4=Ragnar |date=2017-10-27 |editor-last=Corriero |editor-first=Aldo |title=A millennium of north-east Atlantic cod juvenile growth trajectories inferred from archaeological otoliths |journal=PLOS ONE |language=en |volume=12 |issue=10 | | Atlantic cod has been targeted by humans for food for thousands of years,<ref>{{Cite journal |last1=Ólafsdóttir |first1=Guðbjörg Ásta |last2=Pétursdóttir |first2=Gróa |last3=Bárðarson |first3=Hlynur |last4=Edvardsson |first4=Ragnar |date=2017-10-27 |editor-last=Corriero |editor-first=Aldo |title=A millennium of north-east Atlantic cod juvenile growth trajectories inferred from archaeological otoliths |journal=PLOS ONE |language=en |volume=12 |issue=10 |article-number=e0187134 |doi=10.1371/journal.pone.0187134 |issn=1932-6203 |pmc=5659679 |pmid=29077736|bibcode=2017PLoSO..1287134O |doi-access=free }}</ref> and with the advent of modern fishing technology in the 1950s there was a rapid rise in landings.<ref name=":3" /> Cod is caught using a variety of fishing gears including [[Bottom trawling|bottom trawls]], [[Longline fishing|demersal longlines]], [[Seine fishing|Danish seine]], [[jigging]] and [[Handline fishing|hand lines]]. The quantity of cod landed from fisheries has been recorded by many countries from around the 1950s and attempts have been made to reconstruct historical catches going back hundreds of years.<ref name=":3">{{Cite journal |last1=Schijns |first1=Rebecca |last2=Froese |first2=Rainer |last3=Hutchings |first3=Jeffrey A |last4=Pauly |first4=Daniel |date=2021-10-27 |editor-last=Raicevich |editor-first=Sasa |title=Five centuries of cod catches in Eastern Canada |url=https://academic.oup.com/icesjms/article/78/8/2675/6359257 |journal=ICES Journal of Marine Science |language=en |volume=78 |issue=8 |pages=2675–2683 |doi=10.1093/icesjms/fsab153 |issn=1054-3139|doi-access=free |hdl=11250/2833698 |hdl-access=free }}</ref> [[International Council for the Exploration of the Sea|ICES]] and [[Northwest Atlantic Fisheries Organization|NAFO]] collects landings data, alongside other data, which is used to assess the status of the population against management objectives. The landings in the eastern Atlantic frequently exceed 1 million tonnes annually from across 16 populations/management units with landings from the Northeast Atlantic cod population and Iceland accounting for the majority of the landings, Since 1992, when the cod [[Collapse of the Atlantic northwest cod fishery|moratorium]] took effect in Canada, landings in the western Atlantic have been considerably lower than in the eastern Atlantic, generally being less than 50,000 tonnes annually. | ||
===Northwest Atlantic cod=== | ===Northwest Atlantic cod=== | ||
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The Northeast Atlantic has the world's largest population of cod. By far, the largest part of this population is the Northeast Arctic cod, as it is labelled by the [[International Council for the Exploration of the Sea|ICES]], or the Arcto-Norwegian cod stock, also referred to as ''skrei'', a Norwegian name meaning something like "the wanderer", distinguishing it from coastal cod. The Northeast Arctic cod is found in the [[Barents Sea]] area. This stock spawns in March and April along the Norwegian coast, about 40% around the [[Lofoten]] [[archipelago]]. Newly hatched larvae drift northwards with the coastal current while feeding on larval [[copepod]]s. By summer, the young cod reach the Barents Sea, where they stay for the rest of their lives, until their spawning migration. As the cod grow, they feed on [[krill]] and other small crustaceans and fish. Adult cod primarily feed on fish such as [[capelin]] and [[Atlantic herring|herring]]. The northeast Arctic cod also show [[Cannibalism (zoology)|cannibalistic]] behaviour. Estimated stock size was {{cvt|2260000|t|ST}} in 2008. | The Northeast Atlantic has the world's largest population of cod. By far, the largest part of this population is the Northeast Arctic cod, as it is labelled by the [[International Council for the Exploration of the Sea|ICES]], or the Arcto-Norwegian cod stock, also referred to as ''skrei'', a Norwegian name meaning something like "the wanderer", distinguishing it from coastal cod. The Northeast Arctic cod is found in the [[Barents Sea]] area. This stock spawns in March and April along the Norwegian coast, about 40% around the [[Lofoten]] [[archipelago]]. Newly hatched larvae drift northwards with the coastal current while feeding on larval [[copepod]]s. By summer, the young cod reach the Barents Sea, where they stay for the rest of their lives, until their spawning migration. As the cod grow, they feed on [[krill]] and other small crustaceans and fish. Adult cod primarily feed on fish such as [[capelin]] and [[Atlantic herring|herring]]. The northeast Arctic cod also show [[Cannibalism (zoology)|cannibalistic]] behaviour. Estimated stock size was {{cvt|2260000|t|ST}} in 2008. | ||
The North Sea cod stock is primarily fished by [[European Union]] member states, the United Kingdom and Norway. In 1999, the catch was divided among Denmark (31%), Scotland (25%), the rest of the United Kingdom (12%), the Netherlands (10%), Belgium, Germany and Norway (17%). In the 1970s, the annual catch rose to between {{cvt|200000|and|300000|t|ST}}. Due to concerns about [[overfishing]], catch quotas were repeatedly reduced in the 1980s and 1990s. In 2003, ICES stated a high risk existed of stock collapse if then current exploitation levels continued, and recommended a moratorium on catching Atlantic cod in the North Sea during 2004. However, agriculture and fisheries ministers from the [[Council of the European Union]] endorsed the EU/Norway Agreement and set the total allowable catch <!-- (TAC) --> at {{cvt|27300|t|ST}}.<ref>{{cite web|url=http://portunusgroup.com/products/atlantic-cod/|title=Our Products: Atlantic Cod|work=portunusgroup.com|access-date=22 November 2013}}</ref> [[Sustainable seafood advisory lists and certification#Guides and advisory lists|Seafood sustainability guides]], such as the [[Monterey Bay Aquarium]]'s [[Seafood Watch]], often recommend environmentally conscious customers not purchase Atlantic cod. | The North Sea cod stock is primarily fished by [[European Union]] member states, the United Kingdom and Norway. In 1999, the catch was divided among Denmark (31%), Scotland (25%), the rest of the United Kingdom (12%), the Netherlands (10%), Belgium, Germany and Norway (17%). In the 1970s, the annual catch rose to between {{cvt|200000|and|300000|t|ST}}. Due to concerns about [[overfishing]], catch quotas were repeatedly reduced in the 1980s and 1990s. In 2003, ICES stated a high risk existed of stock collapse if then current exploitation levels continued, and recommended a moratorium on catching Atlantic cod in the North Sea during 2004. However, agriculture and fisheries ministers from the [[Council of the European Union]] endorsed the EU/Norway Agreement and set the total allowable catch <!-- (TAC) --> at {{cvt|27300|t|ST}}.<ref>{{cite web|url=http://portunusgroup.com/products/atlantic-cod/|archive-url=https://web.archive.org/web/20100509233101/http://portunusgroup.com/products/atlantic-cod/|url-status=usurped|archive-date=May 9, 2010|title=Our Products: Atlantic Cod|work=portunusgroup.com|access-date=22 November 2013}}</ref> [[Sustainable seafood advisory lists and certification#Guides and advisory lists|Seafood sustainability guides]], such as the [[Monterey Bay Aquarium]]'s [[Seafood Watch]], often recommend environmentally conscious customers not purchase Atlantic cod. | ||
The stock of Northeast Arctic cod was more than four million tons following [[World War II|World War II]], but declined to a historic minimum of {{cvt|740000|t|ST}} in 1983. The catch reached a historic maximum of {{cvt|1343000|t|ST}} in 1956, and bottomed out at {{cvt|212000|t|ST}} in 1990. Since 2000, the spawning stock has increased quite quickly, helped by low fishing pressure. The total catch in 2012 was {{cvt|754131|t|ST}}, the major fishers being Norway and Russia.<ref>{{cite web|url=http://standardgraphs.ices.dk/download/HandlerDownload.ashx?year=2013&EcoRegion=137491&Species=44515|archive-url=https://web.archive.org/web/20140325115725/http://standardgraphs.ices.dk/download/HandlerDownload.ashx?year=2013&EcoRegion=137491&Species=44515|title=ICES Stock Database Disclaimer|access-date=25 March 2014|archive-date=25 March 2014}}</ref> | The stock of Northeast Arctic cod was more than four million tons following [[World War II|World War II]], but declined to a historic minimum of {{cvt|740000|t|ST}} in 1983. The catch reached a historic maximum of {{cvt|1343000|t|ST}} in 1956, and bottomed out at {{cvt|212000|t|ST}} in 1990. Since 2000, the spawning stock has increased quite quickly, helped by low fishing pressure. The total catch in 2012 was {{cvt|754131|t|ST}}, the major fishers being Norway and Russia.<ref>{{cite web|url=http://standardgraphs.ices.dk/download/HandlerDownload.ashx?year=2013&EcoRegion=137491&Species=44515|archive-url=https://web.archive.org/web/20140325115725/http://standardgraphs.ices.dk/download/HandlerDownload.ashx?year=2013&EcoRegion=137491&Species=44515|title=ICES Stock Database Disclaimer|access-date=25 March 2014|archive-date=25 March 2014}}</ref> | ||
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[[Category:Game fish]] | [[Category:Game fish]] | ||
[[Category:Fish described in 1758|Atlantic cod]] | [[Category:Fish described in 1758|Atlantic cod]] | ||
[[Category: | [[Category:Animal taxa named by Carl Linnaeus|Atlantic cod]] | ||
[[Category:Canadian cuisine]] | [[Category:Canadian cuisine]] | ||
[[Category:New England | [[Category:Cuisine of New England]] | ||
Latest revision as of 07:00, 3 November 2025
Template:Short description Template:Speciesbox
The Atlantic cod (Template:Plural form: cod; Gadus morhua) is a fish of the family Gadidae, widely consumed by humans. It is also commercially known as cod or codling.[1]Template:Refn
In the western Atlantic Ocean, cod has a distribution north of Cape Hatteras, North Carolina, and around both coasts of Greenland and the Labrador Sea; in the eastern Atlantic, it is found from the Bay of Biscay north to the Arctic Ocean, including the Baltic Sea, the North Sea, Sea of the Hebrides,[2] areas around Iceland and the Barents Sea.
Atlantic cod can live for up to 25 years and typically grow up to Template:Cvt, but individuals in excess of Template:Cvt and Template:Cvt have been caught.[3][4] They will attain sexual maturity between ages two and eight with this varying between populations and has varied over time.[5][6]
Colouring is brown or green, with spots on the dorsal side, shading to silver ventrally. A stripe along its lateral line (used to detect vibrations)[7] is clearly visible. Its habitat ranges from the coastal shoreline down to Template:Convert along the continental shelf.
Atlantic cod is one of the most heavily fished species. Atlantic cod was fished for a thousand years by north European fishers who followed it across the North Atlantic Ocean to North America. It supported the US and Canadian fishing economy until 1992, when the Canadian Government implemented a ban on fishing cod. Several cod stocks collapsed in the 1990s (decline of more than 95% of maximum historical biomass) and have failed to fully recover even with the cessation of fishing.[8] This absence of the apex predator has led to a trophic cascade in many areas.[8] Many other cod stocks remain at risk. The Atlantic cod is labelled vulnerable on the IUCN Red List of Threatened Species, per a 1996 assessment that the IUCN notes needs updating.[9] A 2013 assessment covering only Europe shows the Atlantic cod has rebounded in Europe, and it has been relabelled least concern.[10]
Dry cod may be prepared as unsalted stockfish,[11][12] and as cured salt cod or clipfish.Template:Refn
Taxonomy
The Atlantic cod is one of three cod species in the genus Gadus along with Pacific cod and Greenland cod. A variety of fish species are colloquially known as cod, but they are not all classified within the Gadus, though some are in the Atlantic cod family, Gadidae.
Behaviour
Shoaling
Atlantic cod are a shoaling species and move in large, size-structured aggregations. Larger fish act as scouts and lead the shoal's direction, particularly during post spawning migrations inshore for feeding. Cod actively feed during migration and changes in shoal structure occur when food is encountered. Shoals are generally thought to be relatively leaderless, with all fish having equal status and an equal distribution of resources and benefits.[14] However, some studies suggest that leading fish gain certain feeding benefits. One study of a migrating Atlantic cod shoal showed significant variability in feeding habits based on size and position in the shoal. Larger scouts consumed a more variable, higher quantity of food, while trailing fish had less variable diets and consumed less food. Fish distribution throughout the shoal seems to be dictated by fish size, and ultimately, the smaller lagging fish likely benefit from shoaling because they are more successful in feeding in the shoal than they would be if migrating individually, due to social facilitation.[15]
Predation
Atlantic cod are apex predators in the Baltic and adults are generally free from the concerns of predation.[16] Juvenile cod, however, may serve as prey for adult cod, which sometimes practice cannibalism. Juvenile cod make substrate decisions based on risk of predation. Substrates refer to different feeding and swimming environments. Without apparent risk of predation, juvenile cod demonstrated a preference for finer-grained substrates such as sand and gravel-pebble. However, in the presence of a predator, they preferred to seek safety in the space available between stones of a cobble substrate. Selection of cobble significantly reduces the risk of predation. Without access to cobble, the juvenile cod simply tries to escape a predator by fleeing.
Additionally, juvenile Atlantic cod vary their behaviour according to the foraging behaviour of predators. In the vicinity of a passive predator, cod behaviour changes very little. The juveniles prefer finer-grained substrates and otherwise avoid the safer kelp, steering clear of the predator. In contrast, in the presence of an actively foraging predator, juveniles are highly avoidant and hide in cobble or in kelp if cobble is unavailable.[17]
Heavy fishing of cod in the 1990s and the collapse of American and Canadian cod stocks resulted in trophic cascades. As cod are apex predators, overfishing them removed a significant predatory pressure on other Atlantic fish and crustacean species. Population-limiting effects on several species including American lobsters, crabs, and shrimp from cod predation have decreased significantly, and the abundance of these species and their increasing range serve as evidence of the Atlantic cod's role as a major predator rather than prey.[16]
Swimming
Atlantic cod have been recorded to swim at speeds of a minimum of Template:Cvt and a maximum of Template:Cvt with a mean swimming speed of Template:Cvt. In one hour, cod have been recorded to cover a mean range of Template:Cvt. Swimming speed was higher during the day than at night. This is reflected in the fact that cod more actively search for food during the day. Cod likely modify their activity pattern according to the length of daylight, thus activity varies with time of year.[18]
Response to changing temperatures
Swimming and physiological behaviours change in response to fluctuations in water temperature. Respirometry experiments show that heart rates of Atlantic cod change drastically with changes in temperature of only a few degrees. A rise in water temperature causes marked increases in cod swimming activity. Cod typically avoid new temperature conditions, and the temperatures can dictate where they are distributed in water. They prefer to be deeper, in colder water layers during the day, and in shallower, warmer water layers at night. These fine-tuned behavioural changes to water temperature are driven by an effort to maintain homeostasis to preserve energy. This is demonstrated by the fact that a decrease of only Template:Convert caused a highly costly increase in metabolic rate of 15–30%.[19]
Feeding and diet
The diet of the Atlantic cod consists of fish such as herring, capelin (in the Eastern Atlantic Ocean), and sand eels, as well as mollusks, tunicates, comb jellies, crustaceans, echinoderms and sea worms.[20] Stomach sampling studies have discovered that small Atlantic cod feed primarily on crustaceans, while large Atlantic cod feed primarily on fish.[21] In certain regions, the main food source is decapods with fish as a complementary food item in the diet.[22] Wild Atlantic cod throughout the North Sea depend, to a large extent, on commercial fish species also used in fisheries, such as Atlantic mackerel, haddock, whiting, Atlantic herring, European plaice, and common sole, making fishery manipulation of cod significantly easier.[21] Ultimately, food selection by cod is affected by the food item size relative to their own size. However, providing for size, cod do exhibit food preference and are not simply driven by availability.[21]
Atlantic cod practice some cannibalism. In the southern North Sea, 1–2% (by weight) of stomach contents for cod larger than Template:Cvt consisted of juvenile cod. In the northern North Sea, cannibalism was higher, at 10%.[21] Other reports of cannibalism have estimated as high as 56% of the diet consists of juvenile cod.[23]
When hatched, cod larvae are altricial, entirely dependent on a yolk sac for sustenance until mouth opening at ~24 degree days.[24] The stomach generally develops at around 240 degree days.[24] Before this point the intestine is the main point of food digestion using pancreatic enzymes such as trypsin.[24]
Reproduction
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Spawning female in captivity
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Juveniles on a wreck in the North Sea
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Atlantic cod juvenile
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Adult
Atlantic cod will attain sexual maturity between ages two and eight with this varying between different populations and has also varied over time with a population.[5][6] Their gonads take several months to develop and most populations will spawn from January to May.[25][26] For many populations, the spawning grounds are located in a different area from the feeding grounds so require the fish to migrate in order to spawn. On the spawning area, males and females will form large schools. Based on behavioral observations of cod, the cod mating system has been likened to a lekking system, which is characterized by males aggregating and establishing dominance hierarchies, at which point females may visit and choose a spawning partner based on status and sexual characteristics.[23] Evidence suggests male sound production and other sexually selected characteristics allow female cod to actively choose a spawning partner. Males also exhibit aggressive interactions for access to females.[27]
Atlantic cod are batch spawners, in which females will spawn approximately 5–20 batches of eggs over a period of time with 2–4 days between the release of each batch.[28][29] Each female will spawn between 2 hundred thousand and 15 million eggs, with larger females spawning more eggs.[30] Females release gametes in a ventral mount, and males then fertilize the released eggs. The eggs and newly hatched larvae float freely in the water and will drift with the current, with some populations relying upon the current to transport the larvae to nursery areas.[31]
Parasites
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Atlantic cod act as intermediate, paratenic, or definitive hosts to a large number of parasite species: 107 taxa listed by Hemmingsen and MacKenzie (2001)[32] and seven new records by Perdiguero-Alonso et al. (2008).[32] The predominant groups of cod parasites in the northeast Atlantic were trematodes (19 species) and nematodes (13 species), including larval anisakids, which comprised 58.2% of the total number of individuals.[32] Parasites of Atlantic cod include copepods, digeneans, monogeneans, acanthocephalans, cestodes, nematodes, myxozoans, and protozoans.[32]
Fisheries
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Atlantic cod has been targeted by humans for food for thousands of years,[34] and with the advent of modern fishing technology in the 1950s there was a rapid rise in landings.[35] Cod is caught using a variety of fishing gears including bottom trawls, demersal longlines, Danish seine, jigging and hand lines. The quantity of cod landed from fisheries has been recorded by many countries from around the 1950s and attempts have been made to reconstruct historical catches going back hundreds of years.[35] ICES and NAFO collects landings data, alongside other data, which is used to assess the status of the population against management objectives. The landings in the eastern Atlantic frequently exceed 1 million tonnes annually from across 16 populations/management units with landings from the Northeast Atlantic cod population and Iceland accounting for the majority of the landings, Since 1992, when the cod moratorium took effect in Canada, landings in the western Atlantic have been considerably lower than in the eastern Atlantic, generally being less than 50,000 tonnes annually.
Northwest Atlantic cod
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The Northwest Atlantic cod has been regarded as heavily overfished throughout its range, resulting in a crash in the fishery in the United States and Canada during the early 1990s.
Newfoundland's northern cod fishery can be traced back to the 16th century. On average, about Template:Cvt of cod were landed annually until the 1960s, when advances in technology enabled factory trawlers to take larger catches. By 1968, landings for the fish peaked at Template:Cvt before a gradual decline set in. With the reopening of the limited cod fisheries in 2006, nearly Template:Cvt of cod were hauled in. In 2007, offshore cod stocks were estimated at 1% of what they were in 1977.[36]
Technologies that contributed to the collapse of Atlantic cod include engine-powered vessels and frozen food compartments aboard ships. Engine-powered vessels had larger nets, greater range, and better navigation. The capacity to catch fish became limitless. In addition, sonar technology gave an edge to detecting and catching fish. Sonar was originally developed during World War II to locate enemy submarines, but was later applied to locating schools of fish. These new technologies, as well as bottom trawlers that destroyed entire ecosystems, contributed to the collapse of Atlantic cod. They were vastly different from old techniques used, such as hand lines and long lines.Script error: No such module "Unsubst".
The fishery has only recently begun to recover, and may never fully recover because of a possibly stable change in the food chain. Atlantic cod was a top-tier predator, along with haddock, flounder and hake, feeding upon smaller prey, such as herring, capelin, shrimp, and snow crab.[8] With the large predatory fish removed, their prey have had population explosions and have become the top predators, affecting the survival rates of cod eggs and fry.
In the winter of 2011–2012, the cod fishery succeeded in convincing NOAA to postpone for one year the planned 82% reduction in catch limits. Instead, the limit was reduced by 22%. The fishery brought in $15.8 million in 2010, coming second behind Georges Bank haddock among the region's 20 regulated bottom-dwelling groundfish. Data released in 2011 indicated that even closing the fishery would not allow populations to rebound by 2014 to levels required under US federal law. Restrictions on cod effectively limit fishing on other groundfish species with which the cod swim, such as flounder and haddock.[37]
Northeast Atlantic cod
The Northeast Atlantic has the world's largest population of cod. By far, the largest part of this population is the Northeast Arctic cod, as it is labelled by the ICES, or the Arcto-Norwegian cod stock, also referred to as skrei, a Norwegian name meaning something like "the wanderer", distinguishing it from coastal cod. The Northeast Arctic cod is found in the Barents Sea area. This stock spawns in March and April along the Norwegian coast, about 40% around the Lofoten archipelago. Newly hatched larvae drift northwards with the coastal current while feeding on larval copepods. By summer, the young cod reach the Barents Sea, where they stay for the rest of their lives, until their spawning migration. As the cod grow, they feed on krill and other small crustaceans and fish. Adult cod primarily feed on fish such as capelin and herring. The northeast Arctic cod also show cannibalistic behaviour. Estimated stock size was Template:Cvt in 2008.
The North Sea cod stock is primarily fished by European Union member states, the United Kingdom and Norway. In 1999, the catch was divided among Denmark (31%), Scotland (25%), the rest of the United Kingdom (12%), the Netherlands (10%), Belgium, Germany and Norway (17%). In the 1970s, the annual catch rose to between Template:Cvt. Due to concerns about overfishing, catch quotas were repeatedly reduced in the 1980s and 1990s. In 2003, ICES stated a high risk existed of stock collapse if then current exploitation levels continued, and recommended a moratorium on catching Atlantic cod in the North Sea during 2004. However, agriculture and fisheries ministers from the Council of the European Union endorsed the EU/Norway Agreement and set the total allowable catch at Template:Cvt.[39] Seafood sustainability guides, such as the Monterey Bay Aquarium's Seafood Watch, often recommend environmentally conscious customers not purchase Atlantic cod.
The stock of Northeast Arctic cod was more than four million tons following World War II, but declined to a historic minimum of Template:Cvt in 1983. The catch reached a historic maximum of Template:Cvt in 1956, and bottomed out at Template:Cvt in 1990. Since 2000, the spawning stock has increased quite quickly, helped by low fishing pressure. The total catch in 2012 was Template:Cvt, the major fishers being Norway and Russia.[40]
Baltic cod
Decades of overfishing in combination with environmental problems, namely little water exchange, low salinity and oxygen-depletion at the sea bottom, caused major threats to the Baltic cod stocks.
There are at least two populations of cod in the Baltic Sea: One large population that spawns east of Bornholm and one population spawning west of Bornholm. Eastern Baltic cod is genetically distinct and adapted to the brackish environment. Adaptations include differences in hemoglobin type, osmoregulatory capacity, egg buoyancy, sperm swimming characteristics and spawning season. The adaptive responses to the environmental conditions in the Baltic Sea may contribute to an effective reproductive barrier, and thus, eastern Baltic cod can be viewed as an example of ongoing speciation.[41] Due to drastically low cod population sizes, commercial fishing of eastern Baltic cod is prohibited since 2019. However, unfavourable environmental conditions in the eastern Baltic Sea, i.e., low salinity and increasing oxygen-depletion at the sea bottom, led to presently only the Bornholm Basin (Southern Baltic Sea) having sufficient conditions for successful reproduction of eastern Baltic cod.[42]
The western Baltic cod consists of one or several small subpopulations that are genetically more similar to the North Sea cod. In the Arkona basin (located off Cape Arkona, Rügen), spawning and migrating cod from both the eastern and western stocks intermingle in proportions that vary seasonally.[43] The immigration of eastern cod into the western Baltic management unit may mask a poor state of the populations in the western management unit.
See also
Notes
References
This article incorporates CC BY-2.0 text from the reference.[32] Template:Reflist
External links
- FishBase
- Codtrace
- The Centre for Environment Fisheries and Aquaculture Science
- The history of the northern cod fishery in Canada
- ICES recommendation for the North Sea Cod stock (2007)
- ICES recommendation for the North East Arctic Cod stock (2007)
- Reports on the status of Canadian fishing stocks, including cod
- Governmental Norwegian fact sheet on North-East Arctic Cod
- Atlantic cod-Gadus morhua fishery profiles Status of Atlantic cod fisheries, summarised in FisheriesWiki
- Template:Eol
- View the Atlantic cod genome in Ensembl
- Government of Canada Seafisheries Landings
- Template:UCSC genomes
- Template:Sealifephotos
Pauly, Daniel, and Ashley McCrea Stru. "Atlantic Cod: Past and Present." Sea Around Us, 21 May 2015, www.seaaroundus.org/atlantic-cod-past-and-present/. Template:Commercial fish topics Template:Cod topics
Template:Taxonbar Template:Authority control
- ↑ Atlantic Cod Template:Webarchive. Seafood Portal.
- ↑ C.Michael Hogan, (2011) Sea of the Hebrides Template:Webarchive. Eds. P. Saundry & C.J.Cleveland. Encyclopedia of Earth. National Council for Science and the Environment. Washington DC.
- ↑ Script error: No such module "citation/CS1".
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- ↑ Cite error: Invalid
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- ↑ Oxford English Dictionary, 3rd ed. "milwell, n." Oxford University Press (Oxford), 2002.
- ↑ Oxford English Dictionary, 1st ed. "stock-fish| 'stockfish, n." Oxford University Press (Oxford), 1917.
- ↑ Atlantic cod NOAA FishWatch. Retrieved 5 November 2012.
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- ↑ Arctic Fisheries Working Group of ICES, published in the ICES Report AFWG CM 2013, ACOM:05. The estimation method was standard virtual population analysis.
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