Pacific herring,Clupea pallasi, recruitment in the Bering Sea and north‐east Pacific Ocean, I: relationships among different populations

We examined recruitment and average weight‐at‐age time series for Pacific herring (Clupea pallasi) populations from the Bering Sea and north‐east Pacific Ocean to determine similarities. Statistical correlation and multivariate clustering methods indicated Pacific herring populations form large‐scale groups. Large year classes occur synchronously among several Pacific herring populations. Multivariate cluster analyses of recruitment and weight‐at‐age data indicated that Bering Sea herring populations are distinct from north‐east Pacific Ocean populations. Within the NE Pacific Ocean, there appear to be three groups of herring populations: a British Columbia group, a south‐east Alaska coastal group, and an outer Gulf of Alaska group. Jackknife and randomization tests indicate these groups are robust and not the result of random chance. Deviations from observed herring population groups were examined for indications of anthropogenic perturbations. The Prince William Sound herring populations did not show any strong deviations corresponding to the oil spill of 1989. There might not yet be enough data since the spill to detect changes in the recruitment or weight‐at‐age data since that time, particularly if oil spill effects were concentrated on the early life history stages.