SEAwise Report on improved predictive models of recruitment under different habitat scenarios and incorporating experimental results

This SEAwise deliverable investigates how environmental conditions and habitat characteristics affect the recruitment dynamics of commercially important fish stocks and their responses to climate change. More than 50 stocks from the Baltic Sea, North Sea, Western Waters and Mediterranean Sea were analysed using statistical and mechanistic models, larval dispersal simulations and experimental studies. Environmental variables, including temperature, salinity, ocean circulation, primary productivity and food availability, were incorporated into stock-recruitment models to assess whether they improve explanatory and predictive performance compared with conventional approaches. For the Mediterranean case studies, environmentally mediated models were developed for European hake, red mullet, deep-water rose shrimp, giant red shrimp, and blue and red shrimp. Several models performed better than corresponding models without environmental covariates and were used to project recruitment under alternative climate scenarios. The results indicate potentially negative effects of warming on hake and red mullet recruitment, while some shrimp stocks may experience more favourable conditions. Overall, the study shows that the influence of environmental drivers is strongly stock-specific. Although environmental covariates often improve the representation of recruitment dynamics, better model fit does not always translate into greater predictive accuracy. The deliverable provides a suite of modelling approaches and results to support ecosystem-based fisheries management and the development of management strategies that are resilient to environmental and climatic change.