Effect of weight loss occuring in winter season on growth of sea bass (Dicentrarchus labrax) reared in the Black Sea
Bilal Akbulut, Temel Şahin
Central Fisheries Research Institute, Şana, Trabzon, TURKEY
In this research, growth performance of sea bass (Dicentrarchus labrax L., 1758) taken from Bodrum were studied in cages on Eastern Black Sea coast and weight loss of this species in the winter season has been investigated. Fish (n=2000) were stocked in a cage on 03 October 1996 and growth performance was followed until 03 November 1997. Fish were fed by hand three times a day, morning, noon and evening, up to they were satisfied. At monthly intervals, 60 fish were taken as sample and their total lengths and body weights measured to determine growth, food conversion, feeding rates and condition factor. Sea water temperature was measured daily. In the experiment, fish with initial mean total length of 11.2±0.136 cm, body weight 20.1±0.771 g and condition factor of 1.35 were stocked in a cage and after 424 days at the end of the experiment, mean values of total length, body weight and condition factor were determined as 23.6±0.249 cm, 176.0±6.64 g and 1.30 respectively. It is observed that growth almost ceased after November when the seawater temperature dropped below 16 °C, the fish have lost weight between December and April, then growth rate increased depending on rising the seawater temperature. To conclude, in Eastern Black Sea conditions, sea water temperature seems to be the main factor limiting the growth. However, the cage fanning provided with good management may be advisable.
Keywords: Sea Bass, Dicentrarchus labrax, weight loss, growth , eastern Black Sea, cage culture