European Eel

Body elongate, cylindrical anteriorly, somewhat compressed posteriorly. Head rather long. Eye always rounded, small in young and yellow eels, large in silver eels. Lower jaw longer than the upper and protruding. Teeth minute, set in bands in both jaws and in a patch on vomer. Gill openings small and vertical, restricted to sides. Dorsal and anal fins confluent with caudal fin; the dorsal fin originates far behind the pectorals; anal fin origin slightly behind anus, well back from origin of dorsal fin. Pectoral fins small and rounded. Pelvic fins absent. D:245-275; A:205-255; Vertebrae: 110-119. Lateral line conspicuous. It has minute, elliptical scales embedded in the skin. Adults in freshwater are greenish-brown on black, yellowish on belly (yellow eel stage), changing to blackish on back and bright silvery on sides and belly (silver-eel stage during spawning migration). Leptocephali and glass-eel stage transparent, elvers greenish-brown; very rarely orange coloured specimens are reported.

From Iceland and Norway (but extremely rare north of Finmark and White Sea) to the African coasts at about 25º N; also in Madeira, Azores and Canary Islands; entering Mediterranean, Black Sea and Sea of Azov; larvae are pelagic in north Atlantic (Bauchot, 1986; Smith, 1990).

To 137 cm (females) or 51 cm (males), but usually 40-60 cm (females) and 30-40 cm (males). Maximum weight: 9 Kg (Wheeler, 1969).

Juveniles inhabit rivers, streams, lake ponds, estuaries and coastal lagoons. They live on the bottom, under stones, in the mud or in crevices.Is an individualist in all its stages. The schools of elvers and young eels which are observed from time to time in estuaries and rivers are a mass response to outward conditions and not of active assembling.As eggs in mid-waters of Sargasso Sea, as leptocephali in North Atlantic surface waters, as glass eels in estuaries and brackish lagoons and later, from elvers to the downstream spawning migration, in streams, ponds and lakes. The downstream spawning migration, usually from late spring to winter, is largely confined to moonless or dark nights and usually in flood water after heavy rain. Very little is known on their oceanic migration; once enter the ocean their migration routes to spawning grounds are not unequivocally known, as few silver eels have been taken at sea.The european eel diet is composed almost entirely of bottom-living organisms: in two British rivers, this species feed mainly on fish (70 and 33 % by volume respectively) and oligochaeta (12 and 18 % by volume respectively); dipteran larvae, and trichopteran and ephemeropteran nymphs, were more numerous and more frequently found than any other food organisms (Sinha & Jones, 1975). According to Deelder (1985), its food includes virtually the whole aquatic fauna (freshwater as well as marine) occurring in the eel's area, augmented with animals living out of water, e.g. worms. On spawning migration the feeding cease. The means of obtaining nutrients during the premetamorphic growth interval is unknown since no food has ever been found in the gut of any eel leptocephalus, although these leptocephalus larvae have been studied for years by many different workers. Pfeiler (1986) suggest that premetamorphic larvae obtain a significant fraction of their nutritional needs by absorbing dissolved organic matter across surface epitelia. A. anguilla is a catadromous semelparous species; when the male yellow eel reach a length of 30-40 cm (usually 6-12 years old) and the females 55-65 cm (10-20 years old), they begin migrating to the sea; at this stage the eyes enlarge, the snout becomes narrower and more pointed and the pectoral fins more lanceolate. The colour changes from yellowish on belly (yellow eel stage) to silver (silver eel stage). Gametogenesis occurs entirely during migration. Schmidt (1922) estimated that the northern area of the Sargasso Sea, in the western North Atlantic, may be the spawning ground of this species. However, this area has not been confirmed by the presence of eggs, small larvae or spawning adults (Baker, 1978). European eels are thought to spawn at ocean depths of 400-700 m in mid-water in late winter and early spring (Bertelsen, 1967). The eggs are pelagic and the leaf-like larvae (leptocephali) of gradually increasing size drifting for 3 years north-east across the Atlantic to arrive on western European coasts (more than this time to arrive to east Mediterranean coasts). Metamorphosis into cylindrical unpigmented "glass eel" takes place over the continental shelf before migrating upstream as pigmented elvers. It has been claimed that the eels in marine habitats are males, while the freshwater eels are females, but this does not appear to be always true: some males are found in fresh water, and some female yellow eels, up to 76 cm in length, are encountered in whole marine habitats. Tsukamoto & Arai (2001) confirm the occurrence of several ecophenotypes for Anguilla japonica.

Exploited at all stages of their freshwater life (as elvers migrating up river, as feeding yellow eels, and as silver eels migrating down river), eel-fishing gear are very diverse: trawls, electric fishing, spears, traps and pots, hooks, weirs, rakes, pound nets, fyke nets, and others. Elvers are caught for eating, but most are used to stock heavily fishes areas or to maintain intensive pond culture of eels, as in Japan. Utilized fresh, dried/salted, smoked and frozen.