Otolith shape is oval. The sulcus runs over more than half the length of the otolith, but is not well developed and open at the ostium. Ostium and cauda are poorly distinguishable. The inside and outside surfaces are smooth, apart from some irregularities at the ventral margin. The margins are rounded in smaller specimens while larger otoliths have a straight ventral margin. The rostrum is rounded and a small rounded antirostrum is also visible. The dorsal side of the otolith can be thicker than the ventral side. The inside of the otolith is convex; the outside is flat to convex. Otoliths are thick but small in relation to fish length and do not exceed 6 mm.
The sulcus becomes less visible when eroded. The antirostrum of the otoliths becomes more distinct with progressed erosion.
Small otoliths are rounder and the sulcus is very indistinct.
Fish length and distribution
Eel can grow up to 120 cm. Eel is a roundfish (ANGUANGU.TIF) that is found in both salt and freshwater. It spawns in salt water (Wheeler, 1978, Nijssen and De Groot, 1987, Muus et al., 1999).
Eel is found in the North Atlantic, North Sea, Baltic and in fresh water systems all over Europe.
Salt water: Fyke
Fresh water: Texel (Netherlands)