Growth of cod in relation to fish size and ration level. In: The propagation of cod Gadus morhua L.: an international symposium, Arendal, 14 - 17 June 1983

Abstract

This study presents the main results of a series of growth experiments on cod with particular reference to ration size, size of the fish and growth and feeding in the spawning season. The experiments were started in 1977 in small laboratory tanks and continued in the period 1979-83 with small tanks, large outdoor tanks and net-pens. The data indicate that cultured cod fed to satiation during their first two years of life grow two to five times faster than natural stocks in the North Atlantic. The relation between growth rate and food intake was shown to be linear and the maintenance ration increased linearly with increasing size. Growth rate decreased with increasing size and a log-log transformation gave a good linear fit. The fast growth of cod seemed to reduce age at first maturation and the cod stopped feeding for several weeks during the stage of late maturation and spawning. A larger weight loss was found for females than for males, average weight losses ranging from 16 to 27%.