Environment-driven trends in fish larval abundance predict fishery recruitment in two temperature reef congeners: mechanisms and implications for management

Abstract

ABSTRACTEnvironmental and biological processes acting on fish larvae were long thought to drive fishery cohort strength, but predictive ability oftentimes fell short and larval abundance is now considered to be more useful as a proxy for spawning stock biomass. In the face of a changing ocean, studies that relate environmental covariates, larval abundance, and fishery recruitment are still worthy of continued research, especially in data-limited contexts. Here we focus on a decades-long popular recreational-only multispecies fishery whose population status and recovery potential are uncertain. We leveraged 54 years of ichthyoplankton data (1963-2016) and a powerful species distribution modeling framework to 1) reconstruct species-specific standardized indices of larval abundance, 2) test these indices as a useful indicator of adult stock status or predictor of future fishery recruitment, and 3) to evaluate spatiotemporal trends in their population dynamics relative to environmental variables. Contrary to expectation, species-specific larval abundance predicted future catch across multiple catch data sets, with recent elevated larval abundance suggesting fishery recovery is imminent. Additionally, we identified strong relationships between environmental variables and species-specific larval abundance, thereby providing additional tools for predicting future fishery recruitment and anticipating population change. Our findings paint a path forward for improving estimates of current and future fishery status under changing natural and anthropogenic influences and the incorporation of ecosystem considerations into fishery management.