Northwest Fisheries Science Center

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Document Type: Journal Article
Center: NWFSC
Document ID: 4663
Title: New target fisheries lead to spatially variable food web effects in an ecosystem model of the California Current
Author: Kristin N. Marshall, I. C. Kaplan, P. S. Levin
Publication Year: 2014
Journal: Ecological Modelling
DOI: 10.1016/j.ecolmodel.2014.07.003
Keywords: food web,fishing,ecosystem model

 Growing human populations put increasing demands on marine ecosystems. Studies have demonstrated the importance of large biomass forage groups in model food webs, but small biomass contributors are often overlooked. Here, we predict the ecosystem effects of three potential future fisheries targeting functional groups that make up only a small proportion of total ecosystem biomass using the California Current Atlantis Model: deep demersal fish such as grenadier (Albatrossia pectoralis and Coryphaenoides acrolepis), nearshore fish such as white croaker (Genyonemus lineatus), and shortbelly rockfish (Sebastes jordani). Using a spatially explicit ecosystem model, we explored individual fishing scenarios for these groups that resulted in abundance levels of 75, 40, 25, and 0 percent of the status quo fishing scenario and a combined fishing scenario simultaneously targeting all three groups. We evaluated the effects on coast-wide biomass and describe variation in affected groups by region. Results indicate that developing fisheries on the proposed targets would have low coast-wide effects on other species.  However, effects varied significantly within the ecosystem, with higher impacts concentrated in the central California region of the model.  Effects of fishing all three groups simultaneously were additive in some cases coastwide, but were not additive at the regional scale. This work provides a framework for evaluating effects of new fisheries and suggests that regional effects should be evaluated within a larger management context.

Theme: Ecosystem Approach to Management for the California Current Large Marine Ecosystem
Foci: Conduct integrated ecosystem assessments that produce metrics and criteria that will improve ecosystem forecasts and predictions.
Characterize ecological interactions (e.g. predation, competition, parasitism, disease, etc.) within and among species to support ecosystem approach to management.