Effects of long-term exposure to ocean acidification conditions on future southern Tanner crab (Chionoecetes bairdi) fisheries management

Abstract

Abstract Demographic models of pre- and post-recruitment population dynamics were developed to account for the effects of ocean acidification on biological parameters that affect southern Tanner crab (Chionoecetes bairdi) larval hatching success and larval and juvenile survival. Projections of stock biomass based on these linked models were used to calculate biological and economic reference points on which fisheries management advice is based and thus provide fisheries managers with strategic advice on the likely long-term consequences of ocean acidification. The models utilized information for southern Tanner crab in the eastern Bering Sea. This information included the monitoring data on which conventional size-structured stock assessments are based, as well as the functional relationships that determine survival based on experiments that evaluated the consequences of ocean acidification over the next 100–200 years on crab larval hatching success, larval survival, and the survival of juvenile crab. The results highlighted that juvenile survival had the largest effect (∼20% decrease over 75 years) on biological and economic reference points, while hatching success, particularly if density dependence occurs after hatching, and larval survival have smaller effects (<10% decrease). Catch and profits would be expected to decrease by >50% in 20 years if natural mortality is affected by ocean acidification. Additional laboratory data on oocyte and embryo development leads to large changes in biological reference points depending on the timing of ocean acidification effects relative to natural mortality. The results highlight the need for experiments to evaluate the longer term physiological effects of ocean acidification on multiple life history stages and to measure indices that directly inform population dynamics models to evaluate future management scenarios.