Monday, August 2, 2010: 4:20 PM
301-302, David L Lawrence Convention Center
Jameal F. Samhouri, Northwest Fisheries Science Center, NOAA Fisheries, Seattle, WA, Cameron Ainsworth, Northwest Fisheries Science Center. NOAA, Seattle, WA, D. Shallin Busch, Conservation Biology, NOAA - Northwest Fisheries Science Center, Seattle, WA, Thomas A. Okey, West Coast Vancouver Island Aquatic Management Board, Port Alberni, BC, Canada and William L. Cheung, School of Environmental Sciences, University of East Anglia, Norwich, United Kingdom
Background/Question/Methods Climate change is creating a warmer and more acidic world ocean. The impacts of changes in these physical variables on individual species are complex, but not completely unknown. Warmer waters will alter species’ bioenergetic rates and biogeographic ranges, while more acidic waters will modify their growth, survival, and fecundity. In some cases, changes in the temperature and carbonate chemistry of marine waters are expected to have interactive effects. However, the consequences of climate change on interactions among species have been little studied. The objective of this study was to explore how increasing ocean temperature and acidification may influence marine food webs in the northeast Pacific Ocean. We simulated temperature-induced shifts in species’ ranges and increased metabolic rates, and acidification-induced declines in production, individually and together, using a set of five Ecopath with Ecosim models. We focused our analyses on predicted changes in fisheries landings, fisheries value, and indicators of community composition.
Results/Conclusions Increasing temperature caused poleward shifts of some commercially-important fishes, introducing novel predator-prey interactions in some cases and modifying the strength of existing interactions in others. Acidification reduced the productivity and biomass of bivalves, gastropods, echinoderms, and cephalopods, exacerbating declines in the biomass of their more specialist predators. Changes in fisheries catch and value varied among models, though stocks of invertivorous flatfish and rockfish generally diminished. Community indicators such as Shannon diversity and mean trophic level were remarkably robust to simulated effects of climate change. The challenge of predicting the cumulative impacts of climate change on species interactions and food web properties is enormous, but must be met if we are to adapt and manage rapidly changing marine ecosystems in the 21st century.
