Comparative investigation of the relationships between otolith weight and size with fish length in Neogobius species in the Southern part of the Caspian Sea

In this study, the relationships between otolith weight and dimensions with fish length were investigated in Neogobius species from Gobiidae. During this research, 149 specimens belong to three species, Neogobius pallasi, N. caspius and N. melanostomus, were collected using hand trawl net from Anzali, in the southwestern part of the Caspian Sea. After removing of otolith from specimens, otolith weight, length and height were recorded. The mean of otolith weight and dimensions were significantly different between three species; N. melanostomus had lower value in these parameters with respect to other species. In N. pallasi and N. caspius, otolith weight showed the highest correlations with fish length. In N. melanostomus, however, in addition to otolith weight, otolith length showed high correlation with fish length. According to the results of this study, probably, otolith weight and dimensions could be used as useful tools for determination of Neogobius species length in studies of trophic relationships in this region.