Effects of temperature and growth hormone on individual growth trajectories of wild-type and transgenic coho salmon Oncorhynchus kisutch.

In this study, individual growth patterns of wild-type and growth-enhanced coho salmon Oncorhynchus kisutch at 8, 12 and 16 degrees C water temperature were followed. Despite large differences among individuals in growth rates, there was generally little variation in the shape of the growth curves among O. kisutch individuals of both genotypes and at all temperatures. Typically, individuals that were relatively large initially were also relatively large at the end of the growth period. The limitation in variation was more pronounced in the growth-enhanced O. kisutch than in the wild type, where the relative size of some individuals reared at 12 and 8 degrees C changed by the end of the trial. As a warmer temperature seems to decrease the plasticity of growth trajectories in wild-type fish, it is possible that global warming will influence the ability of wild fish to adapt their growth to changing conditions.