The effects of different temperature on sexual differentation and development in sea bass (Dicentrarchus labrax L., 1758)

In this study, development and sex differention of sea bass exposed to different temperatures (15, 17 0C and control (mean temperature 15 to 20 0C)) during 30, 60 and 90 days at larval period were investigated. The fish were reared (mean initial live weights and lengths were between 0.0093±0.00006 and 0.0095±0.00004 g, 0.027±0.012 and 0.039±0.001 cm respectively) during 13 months.The highest mean weight and total length were obtained (205,16±0,36 g; 26,91±0,57 cm) for 90 days group of 15 0C. The highest daily growth rate (0,53±0,00), specific growth rate (2.56±0.003) were also found at 90 days group of 15 0C. Moreover, while food efficiency rate (0.55±0.003), food conversion rate (1.82±0.01) and survival rate (70.38±0.25) were observed at the same group of fish, the highest condition factor (1.009±0.65) were determined at the group of 17 0C of 90 days.There were no significant differences between gonadosomatic index values of the groups at the end of the experiment. Differentiation of testicular and ovarian tissues by the influence of temperature applied was seen in the observations of gonad histology.The highest sex reversal rate (female 67.7 %; male % 22.0; intersex % 10.3) was determined in 90 days group of 15 0C.