Otoliths (“earstones”) are small, white structures found in the skull of all bony fish, and composed of mineral crystal. Otoliths provide balance to fish in much the same way that the inner ear provides balance in humans. Each fish has 3 pairs of otoliths, of which usually the Sagitta is the largest one.
The shape and proportional size of the otoliths vary between fish species, and therefore can serve as a good marker for fish identification. Moreover, they exhibit good correlation with body size, and help determine age and growth pattern.
The photographs in this manual show one pair from each species. The photograph shows the otolith pair and milimetric scale, from both the ventral and dorsal views. Otoliths from 30 of Israel’s fresh-water fish species are presented and described in this manual.