Does Climate-Integrated Stock Assessment Improve Management? An American Plaice Example.

Hart, Amanda R.¹, Lisa Kerr¹, Timothy J. Miller², ¹Gulf of Maine Research Institute, Portland, ME, ²NOAA Fisheries, Northeast Fisheries Science Center, Woods Hole, MA

Fisheries management is moving toward ecosystem-based fisheries management, but regulatory frameworks in the U.S. still operate at the single-species level. Climate-integrated stock assessment models may help bridge the gap by drawing on ecosystem processes to account for variability and changes in life history traits, population trends, and distributions. However, the proposed benefits of this approach have not always been realized. We used the Woods Hole Assessment Model (WHAM) to develop assessment models with and without environmental covariates influencing aspects of stock dynamics and tested their performance using Management Strategy Evaluation. American Plaice were used as a case study because they have known changes in productivity and a demonstrated shift in distribution in response to ocean warming that are not explicitly accounted for in the current stock assessment. The strength of environmental drivers on recruitment and catchability were varied across simulations to identify possible thresholds for environmental change, past which climate-integrated assessment models are more likely to result in differential management advice. Our results explore methods to incorporate physical-biological links in single-species stock assessments and explore the long-term consequences for management under climate change.