Climate Indicators of Salmon Survival 12 (original) (raw)

Using studies from the Columbia River, salmon survival and catch measures were correlated with several Pacific Northwest climate indices. Spring chinook survival rate and catch were varied with the Pacific Northwest climate index (PNI), which characterizes temperature and precipitation cycles in the Pacific Northwest. Cool/wet conditions were associated with higher survival and catch while warm/dry conditions were associated with lower stock measures. At a finer temporal scale, the survival of spring chinook from smolt to adult was correlated with the arrival time of smolts into the estuary and the spring transition date, which signals the beginning of spring and coastal upwelling. A match/mismatch hypothesis is suggested to explain how variation in spring transition and estuary entry dates can effect stock survival. The effects of hatchery production and hydrosystem passage on year class strength is also considered in terms of the match/mismatch mechanism.