ANGUILLA VULGARIS : EEL

Order :- APODES or ANGUILLFORMES (Body long and slender. Air bladder with ducts. Gill openings small. Scales minute or absent. Dorsal. caudal and anal fins continuous).

GENUS :- Anguilla

SPECIES :- vulgaris

GEOGRAPHICAL DISTRIBUTION

Anguilla vulgaris is widely distributed in Europe, North Africa, temperate Asia, North America, Mexico, West Indies, Australia and New Zealand. They are not found in Eastern Pacific and South Atlantic.

HABIT AND HABITAT

Anguilla is a fresh-water fish. It is a voracious feeder and catadromous fish and it can live for several hours out of water. The adult eels live in ponds, estuaries, rivers and coastal areas of the sea and damp grass or moss outside water.

GENERAL CHARACTERSTICS OF ANGUILLA VULGARIS : EEL

Commonly known as eel, measuring 1.2 metres in length.
Body is slender, elongated and snake like. Body divisible into head, trunk and tail.
On each side operculum covers the gill slits. Head contains mouth, eyes and nostril.
Dorsal fin, anal fin and caudal fin are joined together forming a continuous fin. Fins are supported by fin rays.
Body is covered by minute scales embedded in the skin and arranged obliquely at right angles to one another forming a curious pattern.
Maxillaries and palatopterygoid present, gill cleft separate and vertebrae greatly enlarged.
Spines absent, gill openings small, air bladder has a ductus pneumaticus. Oviducts absent.
Gills displaced posteriorly with 6 to 22 branchiostegal rays. There are no special accessory organs for breathing air. When on land, probably air is taken through skin.

SPECIAL FEATURES

Eels have peculiar breeding habits and life-histories. Both the American and European eels, when about 60 cm long, put on breeding colours. The green European eel travels about 3,000 miles to spawn in hot waters of West Indies. Upon reaching the coastal waters, green colour changes to silver eyes are enlarged and gonads mature. The fish lays about 10 million eggs, which hatch into pelagic larvae called as Leptocephali. These larvae take homeward journey. On the contrary to present known work, Aristotle thought that they come from ‘entrails of earth’.