Growth of juvenile halibut (Hippoglossus hippoglossus) related to temperature, day length and feeding regime

Experimental studies with farmed juvenile halibut, Hippoglossus hippoglossus, were undertaken to optimize rearing procedures. Extended feeding period and/or day length did not significantly increase growth rates of juvenile halibut of 5 to 20 g wet weight. Growth was strongly affected by temperature, and highest growth rates were obtained at 13°C followed by 10, 16 and 7°C for juveniles of 20 to 90 g. Growth rate declined with size in one of two experiments in this size interval. Q₁₀ of daily growth rate between 7 and 10°C varied from 2.5 to 3.0. Individual growth always varied highly within the temperature treatments (overall range −0.3 – 3.5%·d⁻¹), but significant size rank correlations were maintained during the 12-week experiment. Juvenile halibut grew approximately isometrically from 20 to 90 g. Weight-specific oxygen consumptions of 80 g juveniles averaged 140 and 200 mg O₂ (kg·h)⁻¹ at 10 and 16°C, respectively, and this is comparable to rates measured for other flatfish species.