Multiscale influence of climate on estuarine populations of forage fish: the role of coastal upwelling, freshwater flow and temperature

We examined how local- and regional-scale environmental drivers affect patterns ofabundance and recruitment in 2 abundant and ecologically significant forage fishes (Pacific herring Clupea pallasi and surf smelt Hypomesus pretiosus) in the Skagit River estuary (Puget Sound, Wash-ington, USA). We identified associations between survey catch rates and environmental conditions at2 scales: within-season distributional shifts in response to local environmental conditions, and inter-annual patterns of relative year class strength related to both local- and regional-scale drivers. Usingmonthly data that spanned a 9 yr period, we found that a small proportion (