GROWTH OF JUVENILE HALIBUT (HIPPOGLOSSUS-HIPPOGLOSSUS) RELATED TO TEMPERATURE, DAY LENGTH AND FEEDING REGIME

Experimental studies with farmed juvenile halibut, Hippoglossus hippog lossus, were undertaken to optimize rearing procedures. Extended feedi ng period and/or day length did not significantly increase growth rate s of juvenile halibut of 5 to 20 g wet weight. Growth was strongly aff ected by temperature, and highest growth rates were obtained at 13 deg rees C followed by 10, 16 and 7 degrees C for juveniles of 20 to 90 g. Growth rate declined with size in one of two experiments in this size interval. Q(10) of daily growth rate between 7 and 10 degrees C varie d from 2.5 to 3.0. Individual growth always varied highly within the t emperature treatments (overall range - 0.3 - 3.5%. d(-1)), but signifi cant size rank correlations were maintained during the 12-week experim ent. Juvenile halibut grew approximately isometrically from 20 to 90 g . Weight-specific oxygen consumptions of 80 g juveniles averaged 140 a nd 200 mg O-2 (kg . h)(-1) at 10 and 16 degrees C, respectively, and t his is comparable to rates measured for other flatfish species.