| Climate variability has a large impact on the physical and biological environment of Fraser River sockeye. Using five large-scale indices of climate, the Aleutian Low Pressure Index, the Pacific Decadal Oscillation, the Pacific Circulation Index, the Atmospheric Forcing Index and the Northern Oscillation Index, the association between early marine growth of Birkenhead River and Chilko River sockeye and climate variability was examined. Evidence was presented that suggests that early marine growth of Fraser River sockeye decreases when sockeye enter the ocean in years of intense Aleutian lows and increased sea surface temperature. Furthermore, it was shown that when early marine growth is limited, mean age at maturity increases. Based on the results of this study Fraser River sockeye managers should consider the impacts of climate variations on the future productivity of sockeye through a more comprehensive ecosystem management approach. |
