Growth rates in cultured common wolffish (Anarhicahas lupus) and spotted wolffish (A. minor)

Abstract

Field caught common wolffish (Anarhichas lupus) and spotted wolffish (A. minor) have been raised from fry on dry pellets. The two species have experienced annual fluctuations in temperature between 6 and 12 °C and the results indicates that both species have there best growth rates below 10 °C. With initial average wet weights of 2.6 g (common wolffish) and 6.3 g (spotted wolffish), and at equal experimental conditions, the spotted wolffish reached four times the wet weight of the common wolffish over a period of two years and 10 months, 3.4 and 0.9 kg respectively. The specific growth rate, however, were 0.62 %d^-1 and 0. 58 %d^-1 respectively, indicating only small differences in growth rates in that period. Estimates based upon the fastest growing fish in the experimental groups indicated that at optimum temperature conditions (approx 6 °C) the spotted wolffish will probably reach a total wet weight of 6 kg in two years from start-feeding, while the common wolffish (below 10 °C) will reach a weight of 3 kg in that same period. The common wolffish mature at a size from 0. 5 - 1. 0 kg, while the spotted wolffish mature at a size above 4 kg.