life circle of eel
The European eel
, Anguilla anguilla
, is a
species of eel
, a snake-like, facultatively
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
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
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
. They spend most of their lives in
freshwater, although recent studies on the related Japanese eels
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
of the eel is thought to protect the fish against changes in
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%). 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
such as Anguillicola crassus
barriers such as hydroelectric
plants, and natural changes in the North Atlantic oscillation
and the North Atlantic drift
. Recent work
suggests that PCB pollution
may be a major factor in the
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.
- , 2008.
- Branteviksålen kan vara världens
Image:Ål, Iduns kokbok.jpgImage:Anang u0.gif