Effect of Stock Density on Growth Performance of Juvenile Black Sea Bream (Acanthopagrus schlegeli) in Recirculating Aquaculture System

Abstract

The black Sea Bream is a future promising species in South Korea (aquaculture), although the current production is not the desired because of temperature oscillation. Stock density is considered as one of the factor that can affect the growth performance in aquaculture. The purpose of this work was to evaluate the effect of the stock density on growth performance for black sea bream Acanthopagrus schlegeli cultivated in Recirculating Aquaculture System (RAS) during 7 weeks. The trial was divided in four stock densities (30, 45, 60, 75 fish/ m3-14, 21, 28, 35 kg/m3 respectively) replicate in triplicate. The feed was provided to satiation twice per day (10 am to 6 pm) using the commercial feed for Sea Bream (47 % protein). The water quality parameters were measured daily (9 am to 5 pm), water sample was collected once a week for nitrogen control and 10% of a total water volume (500 l) was changed daily in each system. The growth measurements were analyzed two times, at week 4 and week 7. The results demonstrated that, the survivor rate (week 7), the specific growth rate, weight gain (week 4), the feed conversion rate, daily feed intake (week 4) and condition factor, except feed efficiency were insignificantly affected by stock density (P<0.05). The higher value was recorded in treatment T2 and lower T4. The SGR ranged from 1.7-3.8 (%), the WG (623-2338 g), FCR (0.9-4.8), and K (1.81-2.23). For ranged from (100-80%), DFI (2.15-1.1) and FE (105-36%), the higher performance was observed in treatment T1 and lower T4. The accord with results the most appropriate stock density to cultivate Black Sea Bream Acanthopagrus schlegeli Juveniles in RAS is treatment T3 (60 fish/m3).