Species: European eel (Anguilla anguilla)
Status: Critically Endangered (CR)
Interesting Fact: It is thought that all European eels spawn in the Sargasso Sea after a migration of around 5000 km from European rivers.
European eels are catadromous fish, meaning they spend much of their lives in freshwater but migrate to the sea to breed. Transparent eggs hatch into larvae known as leptocephalli, which drift in the sea for up to three years. Pushed towards the European coast by ocean currents, they then undergo metamorphosis into young, transparent eels known as glass eels. Becoming darker, the young eels, now known as elvers, start to migrate up freshwater streams in large numbers. These eels remain in freshwater for up to 20 years, growing up to 1 metre long. Once sexually mature, the eels migrate back to the Sargasso Sea to spawn. Relatively little is known about the life history and migration routes of the European eels once at sea.
Eel populations have declined in recent years. The threats facing the species are not clear but it is thought that pollution, overfishing, habitat degradation, parasite infection and climate changes are all potential causes of the decline. Regulations are in place to protect these rare eels, including reducing fisheries, restocking, improving habitats and making rivers passable.
Find out more about European eels and their conservation on the eeliad project website.
Lauren Pascoe, ARKive Researcher