Growth, survival and feed efficiency for post-metamorphosed Atlantic cod (Gadus morhua) reared at different temperatures

Two growth trials were completed on post-metamorphosed Atlantic cod (Gadus morhua) for a period of four weeks to determine the optimal temperature for best growth and feed efficiency. The same experiment was repeated twice under similar conditions to determine the effect of four temperature regimes (10, 12, 14 and 16 °C) on randomly selected juvenile cod with an initial weight ranging from 0.34 to 0.51 g. Post-metamorphosed cod grown at 14 and 16 °C were significantly larger at the end of the experiments than the fish grown at 10 or 12 °C, with specific growth rates following a similar trend (p < 0.05). Fish held at 16 °C utilized feed less efficiently than those held at the lower temperatures in experiment II and the highest feed efficiency was observed in fish held at 10 °C (p < 0.05). The results of the feed efficiency and the maximum growth per degree (dG / dTmax) in experiment II suggest that the feed efficiency was likely maximized at a lower temperature than those used in this study. By using data collected from sub-samples of fish in experiment II, maximum growth (Gmax) was estimated at 14.5 °C using a growth temperature model. Cannibalism was a problem in the first experiment but was greatly reduced in experiment II by feeding a larger size feed pellet (2 mm).