Predictive modelling of Atlantic herring distribution in the Northeast Atlantic for informed decision-making. Dataset and calculations

With the withdrawal of the United Kingdom from the European Union, equal access to the British waters under the Common Fisheries Policy ends. This will likely result in reduced catches for the Belgian fishing fleet that mainly targets demersal fish. Alternative fishing grounds and fishing techniques, such as pelagic fishing, could mitigate such losses. This study aims to help pinpoint where and when pelagic fishing could be reintroduced by looking at the geographical distribution of the targeted fish through different seasons. This was done by developing spatiotemporal species distribution models for adult Atlantic herring, Clupea harengus, an economically important pelagic fish species in the Northeast Atlantic, with specific attention to the implications for the Belgian Part of the North Sea. Maximum entropy (Maxent) models were fitted successfully for adult (AUC of 0.7 and TSS of 0.3) and larval (AUC of 0.9 and TSS of 0.7) life stages of herring. The spatiotemporal distribution of adult herring spans a wide area across the Northeast Atlantic throughout the whole year. Regional differences show that adults are most likely to occur in the Belgian Part of the North Sea during winter months, co-occurring with the presence of their larvae. Interestingly, our study also found a negative correlation (-0.7) between winter habitat suitability for larvae in the Belgian Part of the North Sea and autumn North Atlantic Oscillation (NAO) indices. We anticipate that these results will inform policy makers to seasonally manage fisheries in the Belgian Part of the North Sea and the Northeast Atlantic in general.