European Eel

Overview

The European eel is a highly adaptable, snake-like fish known for its complex, catadromous life cycle. It is currently classified as critically endangered due to significant population declines caused by habitat loss, migration barriers, and overexploitation.

Distribution & habitat

This species is widely distributed across the North Atlantic, Baltic, and Mediterranean seas, ranging from northern Norway to the coasts of North Africa. While they are often associated with freshwater rivers, lakes, and streams, they are also frequently found in estuaries, lagoons, and coastal marine environments. They are highly migratory, traveling vast distances between these inland or coastal growth habitats and their oceanic spawning grounds.

Appearance

European eels possess an elongated, cylindrical, snake-like body with a large, pointed head. Unlike many other eel species, they have small, thin scales embedded in their skin. Their dorsal, caudal, and anal fins are continuous, forming a single fringe that runs along the posterior portion of their body. They are equipped with well-developed pectoral fins and small, granular teeth arranged in bands on their jaws.

Biology & behavior

As a catadromous species, the European eel spends most of its life in freshwater or brackish environments before migrating to the ocean to spawn. They are believed to spawn in the Sargasso Sea, though this event has never been witnessed in the wild. The species is panmictic, meaning the entire population shares a single breeding pool. Throughout their development, they transition through several stages, including the transparent "glass eel" phase and the pigmented "yellow eel" phase, before maturing into "silver eels" for their final reproductive migration.