Is the recruitment variability independent of the stock location? Which environmental variables impact the recruitment of fish stocks? New study demonstrates that the anomalies in fish stocks’ recruitment co-varied within the same spawning ground regions, showing that recruitment success is dependent of the local environment.
In this study, Lauréne Pécuchet and co-authors analyzed the effects of the environment on the recruitment variability of 18 assessed stocks in the Baltic and North Seas. They identified groups of stocks for which the recruitment anomalies covaried, most notably a group of pelagics in the Baltic Sea and a group composed of gadoids and herring in the North Sea. The stocks with covarying recruitment were grouped according to their localizations: the North Sea, the Kattegat–Western Baltic, and the Baltic Sea. This suggests the importance of the local environmental variability on the recruitment strength. Environmental variables explained 70% of the survival variability for eight stocks. The variables water current, salinity, temperature, and biomass of competing fish stocks were regularly significant in the models. This study shows the importance of the local environment on the dynamics of stock-recruitment. The results provide evidence of the necessity of including environmental variables in stock assessment for a realistic and efficient management of fisheries.
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