Integrated Assessment of Wind Effects on Central California’s Pelagic Ecosystem

Ecosystem-based management requires integrated physical studies on biological functions. In this study, we hypothesized that seasonal variation in upwelling-favorable winds has differential influences on species of the central California Current pelagic ecosystem. To test this hypothesis, we developed multivariate indicators of upwelling and species’ responses using wind and sea surface temperature (SST) data from buoys and growth and reproductive data for 11 species of fish and seabirds. From previous work, we predicted that winds and SST could be decomposed into winter and spring/summer ‘modes’ of variability, but only a single mode of “winter/spring” environmental variability was observed. We attribute this difference from expectations to the local and shorter-term measurements of winds and SST used in this study. Most species responded to winds and SST variability similarly, but SST was a better predictor of most biological responses. Both SST and wind were better predictors than the traditional upwelling index. Notably, Pacific sardine (Sardinops sajax) was disassociated with the other biotic measurements and showed no relationships with coastal upwelling. The multivariate indicators developed here are particularly appropriate for integrated ecosystem assessments of climatic influences on marine life because they reflect both structure and processes (upwelling and timing/growth/productivity) known to determine functions in marine ecosystems.