Northwest Fisheries Science Center

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Document Type: Journal Article
Center: NWFSC
Document ID: 8712
Title: Risks of ocean acidification on the California Current food web and fisheries: ecosystem model projections
Author: Kristin N. Marshall, I. C. Kaplan, Emma E. Hodgson, A. J. Hermann, D. S. Busch, Paul McElhany, T. E. Essington, C. J. Harvey, E. A. Fulton
Publication Year: 2017
Journal: Global Change Biology
DOI: 10.1111/gcb.13594
Keywords: Ocean acidification,climate change,ecosystem model,fisheries,California Current
The benets and ecosystem services that humans derive from the oceans are threatened by numerous global change stressors, one of which is ocean acidication. Here, we describe the effects of ocean acidication on an upwelling system that already experiences inherently low pH conditions, the California Current. We used an end-to-end ecosystem model (Atlantis), forced by downscaled global climate models and informed by a meta-analysis of the pH sensitivities of local taxa, to investigate the direct and indirect effects of future pH on biomass and sheries revenues. Our model projects a 0.2-unit drop in pH during the summer upwelling season from 2013 to 2063, which results in wide-ranging magnitudes of effects across guilds and functional groups. The most dramatic direct effects of future pH may be expected on epibenthic invertebrates (crabs, shrimps, benthic grazers, benthic detritivores, bivalves), and strong indirect effects expected on some demersal sh, sharks, and epibenthic invertebrates (Dungeness crab) because they consume species known to be sensitive to changing pH. The model’s pelagic community, including marine mammals and seabirds, was much less inuenced by future pH. Some functional groups were less affected to changing pH in the model than might be expected from experimental studies in the empirical literature due to high population productivity (e.g., copepods, pteropods). Model results suggest strong effects of reduced pH on nearshore state-managed invertebrate sheries, but modest effects on the groundsh shery because individual groundsh species exhibited diverse responses to changing pH. Our results provide a set of projections that generally support and build upon previous ndings and set the stage for hypotheses to guide future modeling and experimental analysis on the effects of OA on marine ecosystems and sheries.
Theme: Ecosystem approach to improve management of marine resources
Foci: Understand how climate influences ecosystem variability.
Provide scientific support for the implementation of ecosystem-based management