Kirsten Holsman
Alaska Fisheries Science Center
March 12, 2014

Climate change is expected to impact marine ecosystems globally, with largest changes anticipated for arctic and sub-arctic ecosystems. The 2°C projected increase in mean summer sea-surface temperature for Alaskan marine ecosystems may alter trophic demand, predator and prey distributions, and overall system productivity. We use multi-species food-web and assessment models to link climate-driven changes in physical and trophodynamic conditions to recruitment and survival to help distinguish fishery impacts from large-scale climate pressures. We first used a Regional Ocean Modeling System (ROMS) model coupled to a Nutrient-Phytoplankton-Zooplankton (NPZ) model to produce detailed hindcasts for the period 1970-2012. These results modulate species interactions in a climate-driven Multispecies Statistical Model (MSM) for three groundfish species from the Bering Sea (walleye pollock, Pacific cod, arrowtooth flounder). We first fit the model to hindcast-extracted time series then used downscaled IPCC scenario-driven ROMS/NPZ model estimates of temperature, circulation, and zooplankton abundance to project MSM forward to 2040. Evaluation of differing climate effects on population projections and predator-prey interactions under various IPCC forecast scenarios, recruitment models, and management strategies will be discussed.