Aquatic Ecosystems and Fisheries: Current Research
Salmon MALBEC: Modeling Studies to Support Conservation Planning for Pacific Salmon
- Nate Mantua UW Climate Impacts Group
We have developed a working model of the North Pacific salmon ecosystem that serves as a policy gaming tool with potential to explore the impacts of climate change, hatchery and harvest policies, and changes in freshwater habitat productive capacity at the scale of the North Pacific Ocean. The model is supported by a data base that includes annual run-sizes, catches, escapements, and hatchery releases for a total of 146 regional stock groups of hatchery and wild pink, sockeye, and chum salmon around the Pacific Rim for the period 1950-2002. These data show that hatchery salmon contribute significantly to overall abundance of salmon in some regions and that hatchery chum salmon abundance has exceeded that of wild chum salmon since the early 1980s. For this historical period, various hypotheses about density-dependent interactions in the marine environment are evaluated based on the goodness-of-fit between simulated and observed annual run-sizes.
While the model does not reproduce the observed data for some specific stock groups, it does predict the same overall temporal production pattern of salmon abundance that was observed by reconstructing run sizes with catch and escapement data alone. Our results to date indicate that simulations that include density-dependent interactions in the ocean yield better fits to the observed run-size data than those simulations without density-dependent interactions in the ocean. This suggests that for any level of ocean productivity, the ocean will only support a certain biomass of fish but that this biomass could consist of different combinations of stocks, stock numbers and individual fish size.
University of Washington School of Aquatic and Fishery Sciences; Natural Resources Consultants; University of British Columbia Fisheries Centre; Pangaea Consulting; Simon Fraser University, School of Resource and Environmental Management; The Wild Salmon Center; University of Montana, Flathead Lake Biological Station.
For more publications on CIG's research on climate and PNW aquatic ecosystems, please see CIG Publications.
Mantua, N.J., N.G. Taylor, G.T. Ruggerone, K.W. Myers, D. Preikshot, X. Augerot, N.D. Davis, B. Dorner, R. Hilborn, R.M. Peterman, P. Rand, D. Schindler, J. Stanford, R.V. Walker, and C.J. Walters. (In review). The salmon MALBEC project: A North Pacific-scale study to support salmon conservation planning. Submitted to Proceedings of the NPAFC BASIS Symposium.