Comparative study on the morphology and the composition of the otoliths in the teleosts

Abstract

Conclusion. Saccular otoliths of teleosts were mostly larger than utricular otoliths, which might relate to the three-dimensional movement. The large and heavy otolith may be better suited in saccules of the bottom and reef fishes. The quantities of iron in lagenar otoliths were found to be lower than those of birds. The function of the fish lagena remains to be elucidated by further studies. Objective. To evaluate the morphological characteristics and the chemical composition of the otoliths in fishes as related to behaviour and habitat. Materials and methods. We studied the morphology of the otoliths of 18 genera of fishes (81 samples) divided into 3 groups: saltwater fish (13 genera), freshwater fish except for the carp family (3 genera) and carp family fish (2 genera). The otoliths and the living environments were compared. The chemical composition was analysed using a synchrotron X-ray fluorescence analyser. Results. Bottom fishes generally have larger saccular otoliths, and migrating fishes have smaller saccular otoliths. In comparing the bottom/reef fishes and the migrating fishes in salt water, the former tended to have larger saccular otoliths. In saltwater bottom fishes the tendency was found that the thinner the head, the larger was the saccular otolith. We found significant quantities of iron, zinc and manganese in the lagenar otoliths.

• Otolith
• habitat
• carp family
• iron
• magnetic system