Ruffe
Otolith description
The general shape of the otolith is ovally rounded. The sulcus runs straight over of the length of the otolith. The sulcus is clearly visible, wide and open at the ostium. Ostium and cauda are separated by a slight narrowing of the sulcus. The ostium is slightly wider and shorter than the cauda. The surface of the inside and outside is smooth. The dorsal margin is lobate. The ventral and dorsal margins are rounded. The rostrum is distinct and rounded, while the antirostrum is small and rounded. The posterior end is pointed. The inside is convex and the outside slightly concave. The otolith is thick.
Otoliths of ruffe resemble those of juvenile bass Dicentrarchus labrax and juvenile perch Perca fluviatilis. The sulcus of ruffe otoliths is straight and not pointing down at the posterior. Otoliths of ruffe are thicker and more lobate at the margins than both juvenile bass and perch.
When eroded the sulcus and rostrum remain visible, while the margins are smoothed.
Fish length and distribution
Ruffe can grow up to 25 cm. Ruffe is a schooling fresh water fish found in lowland rivers and lakes. It is also found in the brackish waters of the Baltic. Ruffe is found near the bottom in small schools. Spawning takes place from March to June (Wheeler, 1978, Nijssen and De Groot, 1987).
Ruffe is very common and found in fresh waters throughout Europe and in the brackish waters of the Baltic.
Sample origin
Northern part of the Netherlands.