An example output from a multi-species stock assessment model that accounts for climate effects on future fished and unfished biomass estimates.
The North Pacific Fisheries Management Council (NPFMC) has stated that one of its four priority objectives is to incorporate and monitor effects of climate change on Bering Sea and Aleutian Islands marine ecosystems and their dependent fisheries.
Thus, REEM program scientists (K. Aydin, K. Holsman, I. Ortiz, and E. Moffitt) and Status of Stocks and Multispecies Assessment (SSMA) program scientist J. Ianelli are working to address this council objective using a multi-species stock-assessment model (MSM).
Climate change is expected to impact marine ecosystems globally, with the 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.
REEM program scientists are collaborating with other AFSC and Pacific Marine Environmental Laboratory (PMEL) scientists to use multi-species food-web and assessment models to link changes in the physical environment and food-web to recruitment and survival and help distinguish fishery impacts from large-scale climate pressures.
Recently, model runs have been completed for the Bering Sea using a 10km2 Regional Ocean Modeling System (ROMS) model coupled to a Nutrient-Phytoplankton-Zooplankton (NPZ) model to produce detailed hindcasts for the period 1970-2012 and forecasts using Intergovernmental Panel on Climate Change (IPCC) scenarios through 2040. These results drive a climate-driven Multispecies Statistical Model (MSM) for use in a management strategy evaluation of three groundfish species from the Bering Sea (walleye pollock, Pacific cod, arrowtooth flounder).
First, ROMS model results modulate bioenergetics, food supply, growth, recruitment, and species overlap (i.e., functional responses and predation mortality) as fit in the MSM using hindcast-extracted time series. Then the MSM model is applied to downscaled IPCC climate projections via a ROMS and NPZ model projection of temperature, circulation, and zooplankton abundance.
Results of model simulations have helped REEM scientists understand and predict how future climate driven changes to the system may impact predation and fishery harvest limits.
