Abstract

Groupers are commonly encountered reef-associated predators that mediate lower trophic levels and have supported large artisanal fisheries in the Caribbean for over a century. Increasing water temperatures and human exploitation have been shown to be significant drivers in the distribution and abundance of marine species. While prior studies have projected the effects of climate change on groupers and forecasted poleward shifts with warming sea surface temperatures, there is a need to develop more robust historical baselines using fisheries-independent data in order to better predict the future direction and magnitude of change in grouper fisheries. In this study, we examine nearly 30 years of citizen science fish monitoring data from the Reef Environmental Education Foundation (REEF) and use a spatiotemporal model to show how grouper abundance and habitat use has historically varied in shallow Caribbean waters. We found considerable declines in abundance between 1994 and 2022 and that grouper population centers have shifted southward. Our results highlight that increasing sea temperature does not always lead to poleward shifts in marine taxa. Grouper abundance is a function of complex region-specific temperature and management impacts. Overall, this work highlights that long-term datasets & habitat-derived spatiotemporal assessments are needed to better contextualize community change at scales relevant to management.