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

Abstract

Environmental and biological processes acting on fish larvae can drive fishery cohort strength, but predictive ability oftentimes falls short, and larval abundance is generally considered more useful as a proxy for spawning biomass. Under a changing ocean, studies that relate environmental covariates, larval abundance, and fishery recruitment are worthy of continued research, especially in data-limited contexts. We focus on a popular, recreational-only, multispecies saltwater bass fishery (genus Paralabrax) whose population status and recovery potential are uncertain. We used 54 years of ichthyoplankton data (1963-2016) and a species distribution model to 1) deconstruct species-specific standardized indices of larval abundance, 2) test these indices as indicators of adult stock status or predictors of future fishery recruitment, and 3) evaluate spatiotemporal trends in their population dynamics relative to environmental variables. Contrary to expectation, species-specific larval abundance predicted future catch, with recent elevated larval abundance suggesting imminent fishery recovery. Additionally, we identified strong relationships with environmental variables, thereby providing additional tools for predicting 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.