The length-weight relationship and some biological characteristics of Tinca tinca (Linnaeus, 1758) in Anzali wetland

The relationship between length and weight and some biological characteristics of Tinca tinca (Linnaeus, 1758) in the Anzali Wetland was investigated. A total of 102 specimens of T. tinca were collected on monthly sampling intervals from spring to winter 2019. The mean total length of fish was 15.97±1.51, minimum 13 and maximum 22.5 cm. The fork length was 15.58±1.55, minimum 12.7 and maximum 22.3 cm. Mean fish weight was 62.64±21.15 g with minimum 30 and maximum 174 g. The obesity factor index was 1.49±0.18 in the whole population and 1.41±0.11 in males and 1.55±0.20 in females with minimum values in autumn and maximum in spring. Mean hepatic index was 1.05±0.76 for the whole population, 1.29±0.89 in males and 0.90±0.63 in females with minimum values in spring and maximum in autumn. The mean gonadosomatic index was 5.62±4.58 for the whole population and 3.35±2.1 in males and 7.02±5.12 in females with the minimum in winter and maximum in spring. The relationship between total length and weight for all fish was W=0.025 L2.8123, female W=0.0363 L2.6907 and male, W=0.0066 L3 .2724. According to the b value of the length-to-weight relationship, T. tinca in the Anzali Wetland has an isometric growth pattern indicating similar growth and length growth rate. In the present study, the obtained CF>1 was obtained indicating a proper feeding conditions of the species in the Anzali Wetland.