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European eel

May 10, 2023

The European eel (Anguilla anguilla)[3] is a species of eel, a snake-like, catadromous fish. They are normally around 60–80 cm (2.0–2.6 ft) and rarely reach more than 1 m (3 ft 3 in), but can reach a length of up to 1.5 m (4 ft 11 in) in exceptional cases.

European eel
CITES Appendix II (CITES)[2]
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Anguilliformes
Family: Anguillidae
Genus: Anguilla
Species:
A. anguilla
Binomial name
Anguilla anguilla
Freshwater range of wild European eel
Synonyms

Muraena anguilla Linnaeus, 1758
Anguilla vulgaris Shaw, 1803
Anguilla malgumora Kaup, 1856
Leptocephalus brevirostris

Eels have been important sources of food both as adults (including jellied eels of East London) and as glass eels. Glass-eel fishing using basket traps has been of significant economic value in many river estuaries on the western seaboard of Europe.

While the species' lifespan in the wild has not been determined, captive specimens have lived over 80 years. A specimen known as "the Brantevik Eel" lived for 155 years in the well of a family home in Brantevik, a fishing village in southern Sweden.[4][5][6]

Conservation status

See also: Freshwater eel poaching and smuggling

The European eel is a critically endangered species.[1] Since the 1970s, the numbers of eels reaching Europe is thought to have declined by around 90% (possibly even 98%). Contributing factors include overfishing, parasites such as Anguillicola crassus, barriers to migration such as hydroelectric dams, and natural changes in the North Atlantic oscillation, Gulf Stream, and North Atlantic drift. Recent work suggests polychlorinated biphenyl (PCB) pollution may be a factor in the decline.[7] TRAFFIC is introducing traceability and legality systems throughout trade change to control the decline and encourage a U-turn on the species.[8] The species is listed in Appendix II of the CITES Convention.[9]

Sustainable consumption

In 2010, Greenpeace International added the European eel to its "seafood red list",[10] and the Sustainable Eel Group launched the Sustainable Eel Standard.[11]

Breeding projects

As the European eel population has been falling for some time, several projects have been started. In 1997, Innovatie Netwerk in the Netherlands initiated a project where they attempted to get European eels to breed in captivity by simulating the 6,500 km (4,000 mi) journey from Europe to the Sargasso Sea with a swimming machine for the fish.[12][13]

The first to achieve some success was DTU Aqua, a part of the Technical University of Denmark. Through a combination of fresh and salt water, as well as hormones, they were able to breed it in captivity in 2006 and make the larvae survive for 4.5 days after hatching.[14] By 2007, DTU Aqua scientists were able to set a new record where the larvae survived for 12 days by feeding the mother eel with a special arginine-enriched diet.[15] At this age the content of the larval yolk sac has been used, the mouth and digestive channel have developed, and it requires feeding. Attempts with various substances failed.[16] Deep water sampling of the presumed habitat of larval European eel in the Sargasso Sea was performed by the Galathea 3 expedition in 2006–07, in the hope of revealing the likely feeding preference at the early stage. Their results indicated that they feed on various planktonic organisms, but especially microscopic jellyfish.[16] A follow-up expedition was performed by DTU's own research ship to the Sargasso Sea region in 2014.[17]

To further the research, the PRO-EEL project, led by DTU Aqua and involving several research institutes elsewhere in Denmark (University of Copenhagen and others), Norway (Norwegian Institute of Fisheries and Food Research and others), the Netherlands (Leiden University and others), Belgium (Ghent University), France (French National Center for Scientific Research and others), Spain (ICTA at Polytechnic University of Valencia) and Tunisia (National Institute of Marine Sciences and Technologies), was started in 2010.[18][19] By 2014, the eel larvae at their facilities typically survive 20–22 days, but the full life cycle has still not been completed in captivity.[20]

Life history

Main article: Eel life history

Much of the European eel's life history was a mystery for centuries, as fishermen never caught anything they could identify as a young eel. Unlike many other migrating fish, eels begin their life cycle in the ocean and spend most of their lives in fresh inland water, or brackish coastal water, returning to the ocean to spawn and then die. In the early 1900s, Danish researcher Johannes Schmidt identified the Sargasso Sea as the most likely spawning grounds for European eels.[21] The larvae (leptocephali) drift towards Europe in a 300-day migration.[22]

When approaching the European coast, the larvae metamorphose into a transparent larval stage called "glass eel", enter estuaries, and many start migrating upstream. After entering their continental habitat, the glass eels metamorphose into elvers, miniature versions of the adult eels. As the eel grows, it becomes known as a "yellow eel" due to the brownish-yellow color of their sides and belly. After 5–20 years in fresh or brackish water, the eels become sexually mature, their eyes grow larger, their flanks become silver, and their bellies white in color. In this stage, the eels are known as "silver eels", and they begin their migration back to the Sargasso Sea to spawn. Silvering is important in an eel's development because it allows for increased levels of the steroid hormone cortisol, which is needed for their migration from fresh water back to the sea.[23] Cortisol plays a role in the long migration because it allows for the mobilization of energy during migration.[24] Also playing a key role in silvering is the production of the steroid 11-Ketotestosterone (11-KT), which prepares the eel for structural changes to the skin to endure the migration from fresh water to saltwater.[25]

Magnetoreception has also been reported in the European eel by at least one study, and may be used for navigation.[26]

  •  

    Life cycle of the European eel

  •  

    Glass eels at the transition from ocean to fresh water

  •  

    Mature silver-stage European eels migrate back to the ocean

Ecology

Parasites

Parasite species infecting the European eel include Bothriocephalus claviceps[27] and a range of other intestinal metazoans.[28]

European eels generally have a low parasite diversity within individuals and ecosystems (component community). The parasite that is most commonly dominant is the acanthocephalan Acanthocephalus lucii.[28]

Commercial fisheries

Global production of European eels in tonnes as reported by the FAO
 
↑  Wild capture, 1950–2010[29]
 
↑  Farmed production, 1950–2010[29]
 
↑  Total production of European eel in thousands of tonnes as reported by the FAO, 1950–2010[29]
 
↑  Main European countries producing farmed European eel

References

  1. ^ a b Pike, C.; Crook, V.; Gollock, M. (2020). "Anguilla anguilla". IUCN Red List of Threatened Species. 2020: e.T60344A152845178. doi:10.2305/IUCN.UK.2020-2.RLTS.T60344A152845178.en. Retrieved 19 November 2021.
  2. ^ "Appendices | CITES". cites.org. Retrieved 14 January 2022.
  3. ^ "Anguilla anguilla". Integrated Taxonomic Information System. Retrieved 11 March 2006.
  4. ^ "World's oldest eel dies in Swedish well". The Local. 8 August 2014.
  5. ^ "Anguilla anguilla (Linnaeus, 1758) European eel". FishBase. fishbase.org. Retrieved 3 January 2017.
  6. ^ Deelder, C. L. (1984). "Synopsis of Biological Data On the Eel Anguilla anguilla (Linnaeus, 1758)" (PDF). www.fao.org. Food and Agriculture Organisation of the United Nations. p. 12. Retrieved 3 January 2017.
  7. ^ "PCBs are killing off eels". New Scientist. 2452: 6. 2006.
  8. ^ "Other Aquatic species – Species we work with at TRAFFIC". www.traffic.org. Retrieved 10 January 2019.
  9. ^ "CITES Appendix listings". www.cites.org. Retrieved 13 November 2019.
  10. ^ Greenpeace International Seafood Red list 10 April 2010 at the Wayback Machine
  11. ^ Sustainable Eel Standard
  12. ^ EOAS magazine, september 2010
  13. ^ Innofisk Volendam breedign project
  14. ^ Ritzau (6 July 2006). Danske forskere får ål til at yngle udenfor Sargassohavet. Politiken. Retrieved 22 April 2017.
  15. ^ Nywold, M. (5 October 2007). Dansk forskergennembrud kan sikre ålens overlevelse. Ingeniøren. Retrieved 22 April 2017.
  16. ^ a b Galathea 3: Åleopdræt. Retrieved 22 April 2017.
  17. ^ DTU (6 November 2014). Danish Eel Expedition 2014. Retrieved 22 April 2017.
  18. ^ PRO-EEL: Partners. Retrieved 22 April 2017.
  19. ^ Wageningen University and Research: PRO-EEL: Reproduction of the European eel: Towards a self-sustaining aquaculture. Retrieved 22 April 2017.
  20. ^ Borup, A.T. (13 December 2014). Ålens kode skal knækkes i Hirtshals. 22 April 2017 at the Wayback Machine Nordjyske. Retrieved 22 April 2017.
  21. ^ Schmidt, J. (1912) Danish researches in the Atlantic and Mediterranean on the life-history of the Fresh-water Eel (Anguilla vulgaris, Turt.). Internationale Revue der gesamten Hydrobiologie und Hydrographie 5: 317-342.
  22. ^ "FAO Fisheries & Aquaculture Anguilla anguilla". Fao.org. 1 January 2004. Retrieved 2 August 2012.
  23. ^ Balm, S. Paul; Durif, Caroline; van Ginneken, Vincent; Antonissen, Erik; Boot, Ron; van Den Thillart, Guido; Verstegen, Martin (2007). "Silvering of European eel (Anguilla anguilla L.): seasonal changes of morphological and metabolic parameters". Animal Biology. 57 (1): 63–77. doi:10.1163/157075607780002014. ISSN 1570-7555.
  24. ^ Dufour, Sylvie; Ginneken, Vincent van; Durif, Caroline; Doornbos, Jorg; Noorlander, Kees; Thillart, Guido van den; Boot, Ron; Murk, Albertinka; Sbaihi, Miskal (1 January 2007). "Endocrine profiles during silvering of the European eel (Anguilla anguilla L.) living in saltwater". Animal Biology. 57 (4): 453–465. doi:10.1163/157075607782232143. ISSN 1570-7563.
  25. ^ Lokman, P. Mark; Vermeulen, Gerard J.; Lambert, Jan G.D.; Young, Graham (1 December 1998). "Gonad histology and plasma steroid profiles in wild New Zealand freshwater eels (Anguilla dieffenbachii and A. australis) before and at the onset of the natural spawning migration. I. Females*". Fish Physiology and Biochemistry. 19 (4): 325–338. doi:10.1023/A:1007719414295. ISSN 1573-5168. S2CID 24194486.
  26. ^ Eels May Use 'Magnetic Maps' As They Slither Across The Ocean
  27. ^ Scholz, T. (1997). "Life-cycle of Bothriocephalus claviceps , a specific parasite of eels". Journal of Helminthology. 71 (3): 241–248. doi:10.1017/S0022149X00015984. PMID 9271472. S2CID 5700982.
  28. ^ a b Kennedy, C. R.; Hartvigsen, R. A. (2000). "Richness and diversity of intestinal metazoan communities in brown trout Salmo trutta compared to those of eels Anguilla anguilla in their European heartlands". Parasitology. 121 (1): 55–64. doi:10.1017/S0031182099006046. PMID 11085225. S2CID 9974499.
  29. ^ a b c Based on data sourced from the FishStat database 7 November 2012 at the Wayback Machine, FAO.

External links

  •   Media related to Anguilla anguilla at Wikimedia Commons

May 10, 2023
european, this, article, needs, additional, citations, verification, please, help, improve, this, article, adding, citations, reliable, sources, unsourced, material, challenged, removed, find, sources, news, newspapers, books, scholar, jstor, november, 2019, l. This article needs additional citations for verification Please help improve this article by adding citations to reliable sources Unsourced material may be challenged and removed Find sources European eel news newspapers books scholar JSTOR November 2019 Learn how and when to remove this template message The European eel Anguilla anguilla 3 is a species of eel a snake like catadromous fish They are normally around 60 80 cm 2 0 2 6 ft and rarely reach more than 1 m 3 ft 3 in but can reach a length of up to 1 5 m 4 ft 11 in in exceptional cases European eelConservation statusCritically Endangered IUCN 3 1 1 CITES Appendix II CITES 2 Scientific classificationKingdom AnimaliaPhylum ChordataClass ActinopterygiiOrder AnguilliformesFamily AnguillidaeGenus AnguillaSpecies A anguillaBinomial nameAnguilla anguilla Linnaeus 1758 Freshwater range of wild European eelSynonymsMuraena anguilla Linnaeus 1758Anguilla vulgaris Shaw 1803Anguilla malgumora Kaup 1856Leptocephalus brevirostrisEdouard Manet 1864 Eels have been important sources of food both as adults including jellied eels of East London and as glass eels Glass eel fishing using basket traps has been of significant economic value in many river estuaries on the western seaboard of Europe While the species lifespan in the wild has not been determined captive specimens have lived over 80 years A specimen known as the Brantevik Eel lived for 155 years in the well of a family home in Brantevik a fishing village in southern Sweden 4 5 6 Contents 1 Conservation status 1 1 Sustainable consumption 1 2 Breeding projects 2 Life history 3 Ecology 3 1 Parasites 4 Commercial fisheries 5 References 6 External linksConservation status EditSee also Freshwater eel poaching and smuggling The European eel is a critically endangered species 1 Since the 1970s the numbers of eels reaching Europe is thought to have declined by around 90 possibly even 98 Contributing factors include overfishing parasites such as Anguillicola crassus barriers to migration such as hydroelectric dams and natural changes in the North Atlantic oscillation Gulf Stream and North Atlantic drift Recent work suggests polychlorinated biphenyl PCB pollution may be a factor in the decline 7 TRAFFIC is introducing traceability and legality systems throughout trade change to control the decline and encourage a U turn on the species 8 The species is listed in Appendix II of the CITES Convention 9 Sustainable consumption Edit In 2010 Greenpeace International added the European eel to its seafood red list 10 and the Sustainable Eel Group launched the Sustainable Eel Standard 11 Breeding projects Edit As the European eel population has been falling for some time several projects have been started In 1997 Innovatie Netwerk in the Netherlands initiated a project where they attempted to get European eels to breed in captivity by simulating the 6 500 km 4 000 mi journey from Europe to the Sargasso Sea with a swimming machine for the fish 12 13 The first to achieve some success was DTU Aqua a part of the Technical University of Denmark Through a combination of fresh and salt water as well as hormones they were able to breed it in captivity in 2006 and make the larvae survive for 4 5 days after hatching 14 By 2007 DTU Aqua scientists were able to set a new record where the larvae survived for 12 days by feeding the mother eel with a special arginine enriched diet 15 At this age the content of the larval yolk sac has been used the mouth and digestive channel have developed and it requires feeding Attempts with various substances failed 16 Deep water sampling of the presumed habitat of larval European eel in the Sargasso Sea was performed by the Galathea 3 expedition in 2006 07 in the hope of revealing the likely feeding preference at the early stage Their results indicated that they feed on various planktonic organisms but especially microscopic jellyfish 16 A follow up expedition was performed by DTU s own research ship to the Sargasso Sea region in 2014 17 To further the research the PRO EEL project led by DTU Aqua and involving several research institutes elsewhere in Denmark University of Copenhagen and others Norway Norwegian Institute of Fisheries and Food Research and others the Netherlands Leiden University and others Belgium Ghent University France French National Center for Scientific Research and others Spain ICTA at Polytechnic University of Valencia and Tunisia National Institute of Marine Sciences and Technologies was started in 2010 18 19 By 2014 the eel larvae at their facilities typically survive 20 22 days but the full life cycle has still not been completed in captivity 20 Life history EditMain article Eel life history Much of the European eel s life history was a mystery for centuries as fishermen never caught anything they could identify as a young eel Unlike many other migrating fish eels begin their life cycle in the ocean and spend most of their lives in fresh inland water or brackish coastal water returning to the ocean to spawn and then die In the early 1900s Danish researcher Johannes Schmidt identified the Sargasso Sea as the most likely spawning grounds for European eels 21 The larvae leptocephali drift towards Europe in a 300 day migration 22 When approaching the European coast the larvae metamorphose into a transparent larval stage called glass eel enter estuaries and many start migrating upstream After entering their continental habitat the glass eels metamorphose into elvers miniature versions of the adult eels As the eel grows it becomes known as a yellow eel due to the brownish yellow color of their sides and belly After 5 20 years in fresh or brackish water the eels become sexually mature their eyes grow larger their flanks become silver and their bellies white in color In this stage the eels are known as silver eels and they begin their migration back to the Sargasso Sea to spawn Silvering is important in an eel s development because it allows for increased levels of the steroid hormone cortisol which is needed for their migration from fresh water back to the sea 23 Cortisol plays a role in the long migration because it allows for the mobilization of energy during migration 24 Also playing a key role in silvering is the production of the steroid 11 Ketotestosterone 11 KT which prepares the eel for structural changes to the skin to endure the migration from fresh water to saltwater 25 Magnetoreception has also been reported in the European eel by at least one study and may be used for navigation 26 Life cycle of the European eel Glass eels at the transition from ocean to fresh water Mature silver stage European eels migrate back to the oceanEcology EditParasites Edit Parasite species infecting the European eel include Bothriocephalus claviceps 27 and a range of other intestinal metazoans 28 European eels generally have a low parasite diversity within individuals and ecosystems component community The parasite that is most commonly dominant is the acanthocephalan Acanthocephalus lucii 28 Commercial fisheries EditThis article is missing information about how eel farming works without captive breeding Please expand the article to include this information Further details may exist on the talk page April 2022 Global production of European eels in tonnes as reported by the FAO Wild capture 1950 2010 29 Farmed production 1950 2010 29 Total production of European eel in thousands of tonnes as reported by the FAO 1950 2010 29 Main European countries producing farmed European eelReferences Edit a b Pike C Crook V Gollock M 2020 Anguilla anguilla IUCN Red List of Threatened Species 2020 e T60344A152845178 doi 10 2305 IUCN UK 2020 2 RLTS T60344A152845178 en Retrieved 19 November 2021 Appendices CITES cites org Retrieved 14 January 2022 Anguilla anguilla Integrated Taxonomic Information System Retrieved 11 March 2006 World s oldest eel dies in Swedish well The Local 8 August 2014 Anguilla anguilla Linnaeus 1758 European eel FishBase fishbase org Retrieved 3 January 2017 Deelder C L 1984 Synopsis of Biological Data On the Eel Anguilla anguilla Linnaeus 1758 PDF www fao org Food and Agriculture Organisation of the United Nations p 12 Retrieved 3 January 2017 PCBs are killing off eels New Scientist 2452 6 2006 Other Aquatic species Species we work with at TRAFFIC www traffic org Retrieved 10 January 2019 CITES Appendix listings www cites org Retrieved 13 November 2019 Greenpeace International Seafood Red list Archived 10 April 2010 at the Wayback Machine Sustainable Eel Standard EOAS magazine september 2010 Innofisk Volendam breedign project Ritzau 6 July 2006 Danske forskere far al til at yngle udenfor Sargassohavet Politiken Retrieved 22 April 2017 Nywold M 5 October 2007 Dansk forskergennembrud kan sikre alens overlevelse Ingenioren Retrieved 22 April 2017 a b Galathea 3 Aleopdraet Retrieved 22 April 2017 DTU 6 November 2014 Danish Eel Expedition 2014 Retrieved 22 April 2017 PRO EEL Partners Retrieved 22 April 2017 Wageningen University and Research PRO EEL Reproduction of the European eel Towards a self sustaining aquaculture Retrieved 22 April 2017 Borup A T 13 December 2014 Alens kode skal knaekkes i Hirtshals Archived 22 April 2017 at the Wayback Machine Nordjyske Retrieved 22 April 2017 Schmidt J 1912 Danish researches in the Atlantic and Mediterranean on the life history of the Fresh water Eel Anguilla vulgaris Turt Internationale Revue der gesamten Hydrobiologie und Hydrographie 5 317 342 FAO Fisheries amp Aquaculture Anguilla anguilla Fao org 1 January 2004 Retrieved 2 August 2012 Balm S Paul Durif Caroline van Ginneken Vincent Antonissen Erik Boot Ron van Den Thillart Guido Verstegen Martin 2007 Silvering of European eel Anguilla anguilla L seasonal changes of morphological and metabolic parameters Animal Biology 57 1 63 77 doi 10 1163 157075607780002014 ISSN 1570 7555 Dufour Sylvie Ginneken Vincent van Durif Caroline Doornbos Jorg Noorlander Kees Thillart Guido van den Boot Ron Murk Albertinka Sbaihi Miskal 1 January 2007 Endocrine profiles during silvering of the European eel Anguilla anguilla L living in saltwater Animal Biology 57 4 453 465 doi 10 1163 157075607782232143 ISSN 1570 7563 Lokman P Mark Vermeulen Gerard J Lambert Jan G D Young Graham 1 December 1998 Gonad histology and plasma steroid profiles in wild New Zealand freshwater eels Anguilla dieffenbachii and A australis before and at the onset of the natural spawning migration I Females Fish Physiology and Biochemistry 19 4 325 338 doi 10 1023 A 1007719414295 ISSN 1573 5168 S2CID 24194486 Eels May Use Magnetic Maps As They Slither Across The Ocean Scholz T 1997 Life cycle of Bothriocephalus claviceps a specific parasite of eels Journal of Helminthology 71 3 241 248 doi 10 1017 S0022149X00015984 PMID 9271472 S2CID 5700982 a b Kennedy C R Hartvigsen R A 2000 Richness and diversity of intestinal metazoan communities in brown trout Salmo trutta compared to those of eels Anguilla anguilla in their European heartlands Parasitology 121 1 55 64 doi 10 1017 S0031182099006046 PMID 11085225 S2CID 9974499 a b c Based on data sourced from the FishStat database Archived 7 November 2012 at the Wayback Machine FAO External links Edit Media related to Anguilla anguilla at Wikimedia Commons Retrieved from https en wikipedia org w index php title European eel amp oldid 1152558750, wikipedia, wiki, book, books, library,

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