What moves European sea bass? Understanding the drivers of spatiotemporal patterns in habitat use and migration of Dicentrarchus labrax in the southern North Sea in support of fisheries management.

The poor state of the data-deficient European seabass in the southern North Sea calls for an informed fisheries management to protect the intertwined socio-economic and ecological stakes at risk. The highly mobile Dicentrarchus labrax is known to move from shallow, inshore feeding grounds in summer to deeper waters offshore in search of warmer temperatures in winter for spawning. Knowledge on these spatiotemporal changes in movement behaviour and distribution is critically limited for seabass in the southern North Sea. The cutting-edge technology of the acoustic data storage tag (ADST) enables the observation of fish movements in the wild. The transmitted acoustic signal of ADSTs can be detected by receiving hydrophones, whenever the tagged fish roams within its detection range. Tag recovery allows to access the data-storage part and reconstruct individual depth and temperature records stored on the tag itself. From 2018 to 2020, 100 sea bass, caught by hand-line fishing in the Belgian Part of the North Sea, will be tagged with ADSTs. To understand seabass spatial dynamics in Belgian waters and, by extension, in the southern North Sea, we will investigate spatiotemporal habitat use within Belgian waters, examine the extent and drivers of seasonal spawning migrations and relate these movement and migration behaviours to patterns in the speciesU+2019 exploitation. As a final objective, the observed spatiotemporal dynamics will be translated into fisheries management recommendations.