European Eel

Etymology The name Anguilla derives from the word for “eel” in many of the various Latin-based languages (modern Spanish: anguila; French: anguille; Italian: anguilla; Portuguese: enguia), and the Latin word anguis, all with the same meaning of ‘snake shaped’.   Description Eel belongs to the family Anguillidae. The body is elongated and snake shaped, covered with a large number of small scales which begin to develop during the third year of life in fresh water. The skin is slimy and scales are unnoticeable. The dorsal colour is dark brown to olive green-brown and the colour of the body changes to white and silvery bluish-gray when they start their migration to the sea. The head is flat on top, the mouth is slightly upper, relatively large, bordered with multiple rows of tiny sharp teeth. There is a large fin that follows the shape of the body with more than 500 soft rays. The females reach a maximum length of 1330 mm   Distribution It is found in all European rivers draining into the Mediterranean, the North and Baltic Seas and in the southern Atlantic to the Canary Islands. It rarely enters the White and Barents Seas, recorded eastward to Pechora. Small numbers enter the Black Sea, migrating east to the Kuban drainage. Occasionally individuals reach the Volga basin through canals. It is stocked in most inland waters. Large parts of the population remain at sea (north-western Atlantic and Mediterranean). Before the construction of hydropower plants on the River Drim, their migration route to Lake Ohrid was open. After the construction, regular stocking was carried out in Lake Ohrid as well as the Glabochica and Shpilje reservoirs in order to preserve the population. However, officially, the Prespa Lakes were never stocked with European eel.   Biology Eels live in freshwater, and spawn in sea water for which it makes a long journey followed by significant anatomical, morphological and physiological changes. The spawning peaks are from the beginning of March until July in the Sargasso Sea, in the western sub-tropical Atlantic (about 26⁰N⁰W)  at a depth of 100-200 m and approximately 20⁰C. Adults die after spawning. Larvae emerging from the egg have a length of about 5 mm. As leptocephali (first eel larval stage), driven by the Gulf Stream and north Atlantic Drift they reach the continental slope at about 65-70 mm As leptocephali (first eel larval stage), driven by the Gulf Stream and north Atlantic Drift they reach the continental slope at about 65-70 mm body length and then metamorphose into glass-eels which enter estuaries. When entering freshwater the body colour changes, pigmentation increases during upriver migration and juveniles are then called ‘elvers’ - young eels. In this phase they reach a length of 16 -18 cm. They can remain 5-14 years (males) and 7-18 years (females) in freshwater. Downstream migration (to the sees) starts in late summer or autumn and adults arrive at the spawning grounds the following spring.   Fishing significance Low. It has very low population numbers.   Threats There is a potential threat to the species from water abstraction, drought, pollution and introduced species which could impact the whole lake. Their high fat content and benthic feeding habits in continental waters make them vulnerable to the bio-accumulation of pollutants, such as heavy metals and organic contaminants that may result in organ damage. Conservation actions Possible stocking.