Economics and Social Sciences Research Program
Regional Impacts and Bioeconomics of North Pacific Crab Stocks
The Economics and Social Science Research (ESSR) program, the AFSC Kodiak Lab, and Dr. André Punt at the University of Washington School of Fishery and Aquatic Sciences are collaborating in the development of bioeconomic models for North Pacific crab stocks to evaluate the biological and economic impacts of ocean acidification and other issues relevant to management.
These models separate life-history stages for growth and mortality of juveniles and adults, include fishery impacts by analyzing catch and effort in both biological and economic terms, and can integrate predictions for trends in ocean pH or other environmental factors.
These models were originally designed to estimate maximum economic yield (MEY) with uncertain recruitments and population dynamics that are based on simplified versions of the full assessment models for each crab stock. Currently, bioeconomic models for Bristol Bay red king crab and eastern Bering Sea snow crab are operational.
|Figure 5. MEY fishing mortality rates converge to F35% for a range of starting points.
Figure 5 shows a hypothetical example with dynamic MEY paths for fishing mortality rates that start from a range of initial conditions and model parameters set to converge to the maximum sustainable yield proxy F35% from the 2010 stock assessment model for EBS snow crab.
Economic parameters in the bioeconomic model for EBS snow crab were calibrated using catch, effort, revenue, and cost data for the post-rationalization period 2006-10 from fish tickets, and the Bering Sea Aleutian Islands Crab Economic Data Report database.
Based on these bioeconomic models, ESSRP has begun developing a joint crab bioeconomic/regional economic model in order to calculate the economic impacts on employment, factor income, and household income of ocean acidification and the resulting consequences on Bristol Bay red king crab and eastern Bering Sea snow crab.
By Michael Dalton and Chang Seung