Otolith biometry of big-scale sand smelt (atherina boyeri risso, 1810) living in yamula dam lake

In this study, sagittal otolith biometry was analyzed in individuals of Atherina boyeri obtained from the Yamula Dam Lake population. In addition, basic biological parameters related to sex ratio, length and weight distribution, length-weight and length-to-length relationships were evaluated. Samples were obtained through commercial fishing activities between March and May 2024. Length measurements (total, fork and standard) were performed on the examined fish and the weight of each individual was determined. Sex discrimination of individuals was made by evaluating the gonads at the macroscopic level. Right and left otoliths were taken from each fish sample, cleaned, dried and stored. Length (OL), height (OH), circumference (OP) and area (OA) values of otoliths were measured and recorded. Six shape indices were determined using otolith morphometric data. Relationships between otolith parameters and fish length were analyzed by exponential regression equation. The average percentage prediction errors were calculated for each relationship. A total of 310 individuals were examined for the study. The sex ratio of the sample was determined as 1.0:0.72. The total length (TB) of the samples varied between 45.83-87.58 mm and their weights varied between 0.40-4.32 g. The length and weight distributions were different between the sexes. The b parameter of the length-weight relationship was calculated as 3.763 for all samples. It was seen that the relationships between otolith parameters and total length were statistically significant (P˂0.001). The average percentage error values in the study were lower than 5%. The relationship between TB-OA (r2>0.850) was determined to be stronger than the other relationships in female and male individuals. While no difference was observed between the right-left regions for all shape indices, differences were detected between the sexes in 3 shape indices (shape factor, circularity and ovality). As a result, it was determined that fish length in Atherina boyeri can be reliably back-calculated using otolith measurements.