Smelt
Otolith description
The shape of the otolith is oval and pointed. The sulcus is straight and runs along the full length of the otolith. It is open and well developed. Ostium and cauda are clearly visible and deep. The ostium is shorter but wider, deeper and more irregular than the cauda. The surface of the inside and outside is smooth. The ventral margin has big lobes, the dorsal margin is irregular and more rounded than the ventral margin. The posterior end is indented and often pointed beneath the cauda. The rostrum of the otolith is well developed and pointed, while the antirostrum is indistinct. The otolith is thick and flat at the inside, while strongly convex at the outside. Otolith length does not exceed 10 mm.
Otoliths of smelt are similar in shape to otoliths of argentinidae and atherinidae, however smelt otoliths are much ticker and have a better developed, wider and deeper sulcus. Otoliths which are > 10 mm in length are always of greater argentine Argentina silus.
In eroded otoliths the sulcus remains straight and clearly visible. The margins and rostrum are smoothed. Of otoliths that have gone through a digestive tract of an animal the rostrum is almost always missing.
Otoliths of juvenile smelt are rounder. The sulcus is indistinct but the otolith is clearly indented at both sides. The rostrum is already distinct and pointed.
Fish length and distribution
Smelt can grow up to 30 cm in marine habitats, while fresh water smelt grows up to 20 cm. Smelt is a pelagic roundfish (OSMEEPER.TIF) found in shore waters and adjoining fresh water bodies. There is a migratory and fresh water stock. The fresh water specimen reach a length of 12 cm, while the migratory fish can be up to 30 cm long. The migratory fish enters the fresh water in winter for spring spawning (Wheeler, 1978, Nijssen and De Groot, 1987, Muus et al., 1999).
Smelt is found near the shores of the North Sea and Baltic. There is also a small population found along the Atlantic coast of Ireland.
Sample origin
Large, migratory specimen: Fyke and Western Wadden Sea. Smaller fish from Lake IJssel.