Depth and sea surface temperature drive post-release condition of reef-associated fishes

Shifting fishing practices and warming waters pose growing challenges to sustainable fisheries management, particularly through their combined effects on post-release survival. This study investigates how depth of capture and sea surface temperature (SST) influence post-release condition – used here as a proxy for short-term, delayed mortality – in five recreationally important, reef-associated fish species along Florida’s Gulf coast: gag ( Mycteroperca microlepis ), gray triggerfish ( Balistes capriscus ), greater amberjack ( Seriola dumerili ), red grouper ( Epinephelus morio ), and red snapper ( Lutjanus campechanus ). Post-release condition was defined based on a combination of swim score and externally visible barotrauma symptoms. Using a long-term observer dataset (2015–2024), we first assessed temporal trends in each predictor and then applied species-specific ordinal logistic regression models to evaluate environmental and biological drivers of post-release condition using data from 2022 to 2024. Models were developed and fit using Bayesian methods to account for parameter uncertainty. Increased fishing station depth, our proxy for capture depth, was a consistent predictor of poorer post-release condition for all species. Meanwhile, SST effects were species-specific, with gray triggerfish showing the strongest thermal sensitivity. Long-term fishing depth and SST data were used to back-calculate post-release condition scores over time. Increases in average fishing station depth over time corresponded with worsening predicted condition outcomes in four of five species from 2015 to 2024, suggesting rising post-release mortality risk. These findings highlight the need to integrate environmentally and temporally driven variation in post-release mortality into stock assessments and fishery management decisions. Adjusting fishing seasons to minimize thermal stress and depth-related injury could reduce post-release mortality, supporting climate-resilient management of vulnerable reef fish stocks. • We developed a post-release condition index based on barotrauma and swim score. • Post-release condition was worse in deeper and hotter water. • In the last decade, capture depth increased, leading to poorer post-release outcomes. • Results may inform recreational season management and future stock assessments.