Northwest Fisheries Science Center

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Document Type: Journal Article
Center: NWFSC
Document ID: 8447
Title: The influence of environmental variation on the Columbia River estuarine fish community: Implications for predation on juvenile salmonids
Author: Laurie A. Weitkamp, Thomas P. Good, Donald E. Lyons, Daniel D. Roby
Publication Year: 2016
Journal: North Pacific Anadromous Fish Commission Bulletin
Volume: 6
Pages: 33-44
DOI: 10.23849/npafcb6/33.44.
Keywords: Columbia River Estuary,fish assemblages,avian predation,environmental variables

Predation is often assumed to be the ultimate cause of mortality for juvenile salmonids in marine waters,
but the specific biological or physical factors that infl uence predation are poorly understood. The Columbia River estuary is a useful model ecosystem to understand the relationship between avian predators, alternative prey, environmental variation, and predation on juvenile Pacifi c salmonids (Oncorhynchus spp.). Here, we explore the influence of a suite of local and ocean basin-scale environmental variables on the composition and abundance of the estuarine fi sh assemblage, an important determinant of avian predation on juvenile salmon in the Columbia River estuary. Multivariate analyses indicated that variables representing both freshwater (river fl ow) and marine (ocean temperature, upwelling, plume volume) conditions explained up to half of the variation in the fish assemblage. Many of the same environmental variables were related to the abundances of individual fi sh species. Our results also suggest that the estuarine fi sh assemblage in the future will be quite diff erent from the current one, with likely repercussions for predator-prey interactions. Our results from estuarine habitats provide a useful model for understanding the dynamics of predation in marine habitats, which are much more logistically difficult to study.

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Theme: Recovery and rebuilding of marine and coastal species
Foci: Characterize the population biology of species, and develop and improve methods for predicting the status of populations.
Develop methods to use physiological, biological and behavioral information to predict population-level processes.
Official Citation:

Weitkamp, L.A., T. P. Good, D. E. Lyons, and D. D. Roby.  2016. The influence of environmental variation on the Columbia River estuarine fish community: Implications for predation on juvenile salmonids.  N. Pac. Anad. Fish. Comm. Bull. 6:33-44. doi:10.23849/npafcb6/33.44.