The AFSC is planning research for 2015-17 to evaluate impacts of ocean acidification on commercially important species in the Bering Sea and Gulf of Alaska. The research plan for 2012-14 covered red king crab, Tanner crab, and golden king crab. A paper with results from a bioeconomic model for the valuable Bristol Bay red king crab (BBRKC) fishery was recently accepted for publication at the journal Ecological Modelling. Population dynamics in the BBRKC bioeconomic model included a stage-structured “pre-recruit” model for vulnerable juvenile crab. This pre-recruit model was estimated using data from ocean acidification exposure experiments conducted on juvenile red king crab at the AFSC’s Kodiak Laboratory. Otherwise, population dynamics in the BBRKC bioeconomic model was based on a simplified version of the full BBRKC stock assessment model. The BBRKC bioeconomic model is being used as a template for other crab fisheries. Estimated effects of ocean acidification on juvenile Tanner crab will be implemented for Tanner crab. This pre-recruit model will be linked to a post-recruit model for Tanner, and because Tanner are mainly bycatch in the snow crab fishery, the linked Tanner crab model will also be linked to a post-recruit model for eastern Bering Sea (EBS) snow crab to analyze impacts of different harvest strategies.
Looking ahead to 2015-17, research projects are planned to develop a pre-rerecruit model for snow crab to forecast impacts of ocean acidification on the valuable EBS snow crab fishery to incorporate effects of temperature and climate change on juvenile red king crab, and in addition, to develop bioeconomic models with ocean acidification effects for walleye pollock. Based on results from exposure experiments, direct effects of ocean acidification on growth and survival of juvenile pollock are not expected to be significant. Consequently, the strategy for modeling bioeconomic effects of ocean acidification for finfish will be different from those for crab. Recent work has demonstrated that ocean acidification disrupts the sensory physiology and behavioral responsiveness to critical environmental stimuli in some fishes. The AFSC’s Newport Lab is planning experiments to examine the effects of ocean acidification on the behavior of larval and juvenile walleye pollock. In addition, ocean acidification may have indirect effects on growth of juvenile pollock through changes in prey availability and quality. Results to date on direct effects of pH suggest that growth of walleye pollock is relatively resilient to the direct physiological effects of ocean acidification under optimal foraging conditions. However, it is essential to investigate how the direct effects of pH are manifested in walleye pollock of different or compromised nutritional status as future marine condition will likely be characterized by both food limitation and increasing acidification. To forecast effects of ocean acidification on finfish, we are planning the development of bioeconomic models linked to individual-based or bioenergetics models to make predictions related to growth, fecundity, and survival through the factors of behavior and prey.
