The relationships between otolith size and body length of North African catfish Clarias gariepinus (Burchell, 1822), collected from Sakaryabaşı (the main spring area of the Sakarya River) between July 2014 and November 2014, were examined. Length-weight relationship was also calculated for overall specimens. The wild fish were captured by electrofishing using SAMUS 725MP. A total of 132 individuals ranging from 13.6 to 59.0 cm in total length and from 15.9 to 1755.0 g in weight were sampled. The lagenar otolith (asteriscus) length and height, and the utricular otolith (lapillus) length and width were recorded for each fish. The relationships between otolith measurements and fish somatic growth were described by a non-linear function (power model). The t test revealed no considerable differences in these relationships between left and right otoliths. The ANCOVA test on the relationships between total length and otolith variables did not show significant differences between females and males. All relationships were highly significant and the mean percent prediction errors were less than 7%. The results showed that otolith growth reflected body growth.
