The European eel (Anguilla anguilla) is a species of eel, a snake-like, catadromous fish. They can reach a length of 1.5Â m (4Â ft 11Â in) in exceptional cases, but are normally around 60â"80Â cm (2.0â"2.6Â ft), and rarely reach more than 1Â m (3Â ft 3Â in).
Much of the European eelâs 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 lifecycle in the ocean and spend most of their lives in fresh 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. The larvae (leptocephali) drift towards Europe in a 300-day migration. When approaching the European coast, the larvae metamorphose into a transparent larval stage called "glass eel", enter estuaries, and start migrating upstream. After entering fresh water, 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 5â"20 years in fresh 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.
The European eel is a critically endangered species. 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 plants, and natural changes in the North Atlantic oscillation, Gulf Stream, and North Atlantic drift. Recent work suggests polychlorinated biphenyl pollution may be a factor in the decline.
Eels have been important sources of food both as adults (including the famous 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.
In captivity, European eels can live for very long times. According to a report in The Local, a specimen lived 155 years in the well of a family home in Brantevik, a fishing village in southern Sweden.
In 2010, Greenpeace International added the European eel to its seafood red list.
Decreasing population numbers and breeding projects
For quite some time, the population number of European eels has been falling, so a research project has been started by Innovatie Netwerk, led by Henk Huizing, to see whether it is possible to breed European eels in captivity. The breeding of European eel is very difficult, since eels are generally only able to reproduce after having swum a distance of 6,500Â km (4,000Â mi). In the project, this is being simulated by means of a hometrainer for the fish. Innovatie Netwerk has also started a breeding project, called InnoFisk Volendam.
- Media related to Anguilla anguilla at Wikimedia Commons
- Data related to Anguilla anguilla at Wikispecies
- Froese, Rainer and Pauly, Daniel, eds. (2005). "Anguilla anguilla" in FishBase. 10 2005 version.