Spatial covariation in survival rates of Northeast Pacific pink salmon (Oncorhynchus gorbuscha)

We examined spatial patterns of covariation in indices of survival rate (re siduals from the best-fit stock-recruitment curve) across four decades amon g 43 wild pink salmon (Oncorhynchus gorbuscha) stocks from 14 geographical regions in Washington, British Columbia, and Alaska. We found strong eviden ce of positive covariation among stocks within each region and between cert ain adjacent regions (e.g., correlations from 0.3 to 0.7) but no evidence o f covariation between stocks of distant regions (e.g., separated by 1000 km or more). This suggests that important environmental processes affecting t emporal variation in survival rates of pink salmon from spawners to recruit s operate at regional spatial scales rather than at the larger ocean basin scale. Based on limited fry abundance data, we found that this covariation in spawner-to-recruit survival rates may be strongly influenced by marine p rocesses.