The growth pattern and sexual maturation of Atlantic halibut (Hippoglossus hippoglossus L) reared in large tanks for 3 years

The weight gain of 180 tagged halibut (88 females and 92 males) was studied in a 3-year rearing experiment conducted at 7 degrees C. Two size-classes of young halibut (mean weight 1.8 and 3.2 kg) were stocked at two densities (11 and 22 kg/m(2)). The fish were fed frozen capelin and herring to satiation 6 days a week. The males became sexually mature at an average weight of 3.2 kg and the females at an average weight of 12.7 kg. There were seasonal changes in growth associated with sexual maturation, but, in general, the mean weight of both females and males increased linearly with time. Thus, the absolute growth rate did not change within the size range 2-12 kg (3.2 kg/year) and 2-7 kg (1.4 kg/year) for females and males, respectively. Therefore, it may be more appropriate to compare the growth rates of halibut, using absolute growth rate (kg/year) rather than specific growth rate (SGR, %/day). The shape of the growth curve of each tagged fish was studied by regression analysis and the deviations from linear growth were related to the onset of sexual maturation.