Extreme environmental conditions are associated with poor recruitment of an estuarine sportfish

Across the world, changing ocean conditions are altering the productivity and distribution of fish stocks. These impacts can be observed in coastal and estuarine systems where multiple environmental drivers can shape the population dynamics of fish and invertebrates. Consequently, understanding how key environmental drivers affect fisheries is of the utmost importance. Here, we investigate environment-recruitment relationships of a recreational fish species, spotted seatrout ( Cynoscion nebulosus ), in Alabama, USA. To accomplish this, we first conducted an integrated stock assessment of spotted seatrout to derive recruitment deviations from the assumed stock-recruit relationship. Next, we compared biologically relevant environmental (temperature and salinity) and habitat area (areas meeting salinity and temperature conditions) variables derived from a regional hydrodynamic model to investigate possible linkages with recruitment deviations. We demonstrate how poor recruitment of spotted seatrout is strongly associated with negative salinity anomalies at multiple temporal scales (annual and settlement season), and to a lesser extent, negative temperature anomalies, suggesting that fresher and cooler conditions result in poor recruitment. The environmentally-informed habitat area variables revealed a strong association between poor recruitment and cooler temperatures in oligohaline areas. However, low salinity areas appear to serve as important nursery grounds, likely due to the limited submerged aquatic vegetation (SAV) in meso- and polyhaline areas across the study region. We recommend the use of salinity anomalies as a forecasting tool and future explorations into the relevance of oligohaline SAV to early life history processes of spotted seatrout. The stock assessment results highlight the positive impacts of recent management actions despite environmental variables driving poor recruitment. As changes in coastal waters proceed, the establishment of environment-recruitment relationships could be valuable for monitoring and forecasting changes in recruitment and population productivity of economically relevant species.