Course corrections responding to climate impacts produce divergent effects on population biomass and harvest in fisheries

Climate change will alter ecological dynamics, affecting the relative abundance of species. A primary challenge is whether and how to modify natural resource management practices to address these changes. We explored a model of a harvested fish population experiencing climate-driven changes in demography, finding that climate impacts impose a choice between management strategies that favor fishery yield or population biomass but not both. When climate caused a population’s carrying capacity to increase, or its productivity to decrease, a climate adaptive strategy relying upon this updated information maintained higher population biomass but produced similar or lower yield than fixed management pegged to historical conditions. In contrast, when climate caused a population’s carrying capacity to decrease, or its productivity to increase, a climate adaptive strategy produced greater yield but maintained lower population biomass. Both strategies prevented a population from becoming overfished (too small to achieve maximum yield), but the fixed management strategy could impose more excessive annual harvest rates (overfishing). These insights suggest climate adaptive management may not always outperform a fixed strategy. Yet in U.S. fisheries we found routine assessment of population status modifies demographic parameters, implicitly shifting management reference points that affect fishery yield and population biomass. Participatory processes can illuminate these impacts, creating opportunities to co-develop weightings for conservation and harvest objectives.