European EelAnguilla anguillaMissä ja milloin niitä voi nähdä

The European eel is a long-bodied migratory fish native to European waters and parts of North Africa. It occurs in the Douro, Rhine and Seine river systems, although barriers can restrict its access to upstream habitats. Its remarkable life cycle links rivers, estuaries and coastal waters with the distant Sargasso Sea in the Atlantic Ocean. Numbers have declined severely, with threats including barriers to migration, fishing, habitat loss, pollution and parasites. Protecting connected waterways is important for its recovery.

Size

Usually 40–100 cm long; exceptionally about 130 cm. Females generally grow larger than males.

Weight

Usually less than 2 kg; exceptionally large females can reach about 6.6 kg.

Lifespan

Often 10–20 years, although some remain in continental waters for several decades before migrating to sea.

Status

Critically Endangered (IUCN).

European eels are mainly active at night and often remain concealed during daylight. They shelter beneath stones, among roots or within soft sediment. During their feeding and growth stage, known as the yellow eel stage, they may occupy a relatively small area for extended periods. Activity generally declines as water temperatures fall. Before their ocean migration, they become silver eels, developing larger eyes, darker backs and silvery undersides. Migrating silver eels stop feeding and rely on stored energy for their journey. Their departure from rivers is often associated with autumn conditions, increased flows and dark nights, although timing varies between catchments.

• Its transparent, leaf-shaped ocean larvae are called leptocephali.
• Young eels approaching European coasts become transparent glass eels.
• Unlike salmon, it grows in continental waters and migrates to the ocean to reproduce.
• No European eel spawning event has yet been directly observed in the wild.

Wildlife opportunities depend on the river reach, water levels and species. River-specific viewing months have not been confirmed; general species seasons are not a local sighting forecast.

European eels use rivers, streams, lakes, estuaries and sheltered coastal waters. Some spend much of their growth period in freshwater, while others remain in brackish or marine habitats. In the Douro, Rhine and Seine systems, suitable areas include sheltered margins, tributaries, backwaters and estuaries with accessible cover. Mud, sand, stones, submerged roots and aquatic vegetation can all provide refuges. Dams, weirs and other structures can obstruct upstream movement, while hydropower turbines can endanger eels migrating downstream.

European eels are opportunistic predators that feed mainly on bottom-dwelling animals. Their prey includes insect larvae, worms, crustaceans, molluscs and small fish. Diet changes with eel size and the food available locally, and they also take carrion. A well-developed sense of smell helps them locate food in darkness and murky water.

Common name

European Eel

Scientific name

Anguilla anguilla

Animal group

Fish

Size

Usually 40–100 cm long; exceptionally about 130 cm. Females generally grow larger than males.

Weight

Usually less than 2 kg; exceptionally large females can reach about 6.6 kg.

Lifespan

Often 10–20 years, although some remain in continental waters for several decades before migrating to sea.

Status

Critically Endangered (IUCN).

Identification

Look for a snake-like fish with a continuous fin running along the back, around the tail and forward along the underside. European eels have small pectoral fins just behind the head but no pelvic fins. Their skin looks smooth and slippery, with tiny scales embedded beneath its surface. Feeding-stage eels are typically olive-brown above and yellowish below, while migrating silver eels have darker backs, silvery bellies and noticeably larger eyes.