European eel

European eel
Conservation status
	; Critically Endangered (IUCN 3.1)
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Actinopterygii
Order:	Anguilliformes
Family:	Anguillidae
Genus:	Anguilla
Species:	A. anguilla
Binomial name
	Anguilla anguilla; (Linnaeus, 1758)

The European eel, Anguilla anguilla,^[1] is a species of eel, a snake-like, facultatively catadromous fish. They can reach in exceptional cases a length of 1½ m, but is normally much smaller, about 60–80 cm, and rarely more than 1 m.

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. Research in the 19th and 20th centuries shed some light on the subject, though questions remain. They are generally believed to spawn in the Sargasso Sea and the larvae (Leptocephalus) migrate towards Europe in a three-hundred-day migration (FAO data). As glass eels they reach the coasts of Europe and enter estuaries. Before entering fresh water, the glass eels metamorphose into elvers. They spend most of their lives in freshwater, although recent studies on the related Japanese eels (Anguilla japonica) show that some populations of that species never migrate into freshwater, but spend their lives in marine or estuarine habitats. Those eels living in freshwater undergo changes in pigmentation; their bellies turn yellow. It is assumed that the yellow-coloring acts as a protection from predators as it makes it harder to visually detect the animals. The slimy coating of the eel is thought to protect the fish against changes in salinity.

The European Eel is a critically endangered species.^[2] Since the 1970s, the numbers of eels reaching Europe is thought to have declined by around 90% (possibly even 98%). It is unclear whether this is part of a normal long term cycle, or whether this reflects a decline in eel numbers generally. Potential causes include overfishing, parasites such as Anguillicola crassus, river barriers such as hydroelectric plants, and natural changes in the North Atlantic oscillation, Gulf Stream and the North Atlantic drift. Recent work suggests that PCB pollution may be a major factor in the decline.^[3]

Eels have been important sources of food both as adults (including the famous jellied eels of East London) and as elvers. Elver 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 become very old.^[4]