Energy and ration requirements of juvenile Pacific halibut (Hippoglossus stenolepis) based on energy consumption and growth rates

Abstract

Growth of captive juvenile Pacific halibut was linearly related to energy consumption (J g−1 day−1) at 4°C by the following equation: growth (% body weight (b.w.) day−1)=0–007 (consumption J g−1 day−1)– 0.192; r2=0.81. Weight gain was independent of size for fish between 9 and 7000 g when growth was expressed as a function of consumption in J g−1 day−1. Maintenance ration determined in feeding–growth experiments averaged 27.4 J g−1 day−1 at 4–0°C. Small halibut ate significantly more food than large fish. Single meals following 2 day fasts averaged 4.1% b.w. for halibut under 100 g, 1.72% b.w. for 1.2 kg fish and 1.1% B.W. for 6.8 kg fish. Both large and small size categories of halibut tended to evacuate their meal in about 3 days even though small fish ate relatively larger meals. Minimum estimates for daily ration to achieve growth rates observed in the Gulf of Alaska were approximately 0.5 to 2.4% b.w. day−1 depending on fish size and whether northern shrimp or yellowfin sole were their prey.