Determination of some biological characteristics of golden grey mullet (Chelon auratus, Risso, 1810) caught from Eastern Black Sea

In this study, some biological characteristics of Golden grey mullet (Chelon auratus, Risso, 1810) caught in Rize region between May 2020 and April 2021 were investigated. During the study, a total of 324 specimens consisting of 142 (43.83%) female and 182 male (56.17%) individuals were obtained. The total lengths of all samples ranged between 16.5-38.8 cm, and body weights ranged between 37.76-568.56 g, as well as the mean total length and weight were calculated as 26.9±3.714 cm and 172.475±72.240 g, respectively. The length-weigth relationships were determined as W = 0.0129L2.8641 for females, as W = 0.0150L2.8266 for males and as W = 0.0158L2.8086 for overall. The growth was found negative allometric (b<3) in females, in males and in all individuals. Asymptotic length values (L∞) for females, males and all individuals were calculated as 45.12 cm, 43.97 cm and 44.54 cm, also the growth performance (Φ´) values were calculated as 1.390, 1.382 and 1.386, respectively. The age-length relationships were determined as Lt = 45.12 (1-e-0.205 (t+-1.67)) for females, as Lt = 43.97 (1-e-0.201 (t+1.69)) for males and as Lt = 44.54 (1-e-0.201 (t+1.71)) for overall. The lowest mean condition factor value of the all individuals was found as 0.739±0.103 in June 2020, while the highest mean value was found as 0.963±0.054 in October 2020. The overall Golden grey mullet individuals were found to be distributed between the ages of 1 and 6, as well as 3 year age was the dominant group with a rate of 40.91%. The total length at first maturity was calculated as 21.87 cm for females and 21.45 cm for males. According to the variations in GSI values it was determined that the reproduction of the species started in August and ended in September. The sex ratio (Male: Female) was calculated as 1.28:1.00 and this ratio was statistically different from the expected value of 1:1 as a result of Chi-square test (p<0.05).