Thermal Vulnerability of Reef Fish and Implications for Subsistence Fisheries Throughout the Caribbean.

Dual biodiversity and climate crises have exacerbated declines in global fisheries, resulting in food insecurity for communities that depend on subsistence fishing. As fish populations change and shift their geographic distributions under a changing environment, long-term planning of fisheries management becomes critical for ensuring food security. Here, we first present physiologically informed species distribution models (pSDM) of seven finfish species in the Caribbean that are important for subsistence in some coastal areas. These models identified areas at risk of climate-driven declines and other areas of increased suitability and potential refugia, highlighting how shifts in climate suitability for key finfish species may affect long-term food security in coastal communities. The pSDMs projected mean reductions in climate suitability that ranged from 20% to 66% across all species and scenarios, with more severe decreases under high warming scenarios and in models informed by mean thermal limits across life stages. We then examined whether climate vulnerability estimated from our physiological SDMs explains spatial variation in population biomass trends in the Mesoamerican Reef region using long-term monitoring data. This analysis suggests that changing climate suitability is already associated with spatial shifts in biomass of several species, reducing resource availability for subsistence fisheries in some areas. These models highlight the potential for substantial future shifts in distributions of species important for subsistence in the coming decades. Information on changing climate suitability can support regional planning efforts to help bolster food security and climate resilience within coastal communities.