Growth and reproduction of the greater weever (Trachinus draco L., 1758) along the eastern coast of the Black Sea
Orhan Ak, Yasar Genç
Central Fisheries Research Institute, Vali Adil Yazar St. No: 4, 61250, Kasüstü, Yomra, Trabzon, TURKEY
A total of 636 specimens of the greater weever, Trachinus draco, was collected monthly by bottom trawlers in the Eastern Black Sea. In order to identify some biological features of this species in the Black Sea, reproductive characteristics and growth parameters such as sex ratio, maturity stage, length at first maturity, spawning time, reproduction period, age, length-weight relationship, and condition factor were recorded. The female:male ratio was 1:1.04 (x2 : 0.27, x2 0.05,1=3.84; P>0.05). Mean condition factors of females and males were 0.99055 and 0.95625, respectively. Taking into consideration of gonadosomatic index (GSI) and egg diameter, reproduction occurred in July and August. The age at first maturity was 1+ year and the first reproduction length was 12.01 cm for females. The average diameter of mature egg was 0.91 ± 0.265 mm. Growth parameters of the von Bertalanffy equation were for females and males as follows: L∞ = 32.62 cm, K = 0.18 y-1, to = −1.74 year, and W∞ = 232.54 g, and L∞ = 29.31 cm, K = 0.17 y-1, to = −2.28 year, and W∞ = 232.54 g, respectively. The growth performance index (Ф) was 2.29, 2.17 and 2.36 for females, males and all specimens, respectively. The maximum age was 6 years for females and 5 years for males.
Keywords: Greater weever, Trachinus draco, first maturity length, growth parameters, gonadosomatic index, Black Sea