New target fisheries lead to spatially variable food web effects in an ecosystem model of the California Current

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 small 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 coast-wide, 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. (C) 2014 Published by Elsevier B.V.