Comparative anatomical studies on the otoliths (Ear stones) of some fishes

Abstract

To fulfill this study, the otoliths (ear-stones or crystals) of four fish species were obtained to complete this comparative morphological study. Fifty Tilapia nilotica (Oreochromis niloticus), thirty flat head mullet (Mugil cephalus), thirty Nile catfishes (Clarias lazera) and forty herring fish species (Clupea harengus) were used, where the ear-stones were extracted from the cranial cavity of the fishes, prepared, cleaned by H2O2 and examined anatomically. The results revealed that, there were clear differences between these stones in fish species under investigation. The shape of otolith is ovoid in tilapia, elongated in flat head mullet, rosette shape in catfish and bifid shape in herring fish. These suggest that the morphology of the skulls of different species of fishes could affect the otolithic shape.