Comparative morphological studies on the otoliths (Ear stones or crystals) in some marine and fresh water fishes

Abstract

To overview this study, the otoliths (ear-stones or crystals) of four fish species were obtained to complete this comparative morphological study. Thirty Narrow-barred Spanish mackerel (Scomberomorus commerson), thirty Hard tail jack or blue runner fishes (Caranx crysos), twenty Round sardinella fishes (Sardinella aurita) and twenty Common carp (Cyprinus carpio) fish species were used, where the ear-stones were extracted from the head of the fishes, prepared and examined anatomically. The results revealed that, the topographic characters of four fish otoliths were nearly similar, that all of them were rested on deep fossae on the floor of the cranial cavity just in front of foramen magnum. Significant differences were observed in this work regarding the morphological characters among these stones in fish species under investigation. We conclude that, size and shape of fish otolith might positively relate to its size, weight and age and also, surprisingly, we noted that otolith shape nearly adapted to the external outlines of each fish head. The figures were plotted and the obtained results were discussed with the available literature.