Integration of fisheries and ecological data to support spatial management: The case of blackspot seabream (Pagellus bogaraveo) in the western Mediterranean Sea

Spatial measures are often used to support fisheries management. The European Union, for example, has emphasized the importance of the spatial aspect to protect overfished stocks and to find a better approach to fisheries management. Nevertheless, careful selection of which marine areas to manage with greater precaution is essential to optimize their benefits. In this work, we estimated hot spots of aggregation using a species distribution model developed with template model builder (sdmTMB) on density indices (number of individuals/km²) for blackspot seabream (Pagellus bogaraveo) for two length ranges (< = 20 cm and > 20 cm). We applied the model to scientific bottom trawl surveys conducted in the Alboran Sea (western Mediterranean) and to a dataset of georeferenced commercial catches (CPUE, Catch Per Unit Effort or fishery-dependent data) in the Strait of Gibraltar. In addition, the effects of oceanographic variables on the distribution of species was tested. The identified best distributions for both length ranges are used to determine hot spots of aggregation for the two size classes from 1994 to 2021 in northern Alboran Sea, from 2018 to 2021 in southern Alboran Sea and from 2005 to 2009 in the Strait of Gibraltar area. Identified persistent hot spots (as an hotspot area across all years of the time series) represent key ecological areas for the species that might be considered in future management plans. In the Northern Alboran Sea, 5 ecologically important areas were identified for smaller size individuals and 2 for the larger sized individuals. The overlap with the current effort estimates revealed two areas (one for smaller and one for larger specimens) off Cabo de Gata and Almeria that could have significant ecological impacts with minimal socio-economic disadvantages if further protected. These could be two future management areas (e.g. Fisheries Restricted Area - FRA) that could be important for stock dynamics. The results confirm the ecological preferences of the species that were disentangled by Species Distribution Models (SDMs) as well as its useful contribution to support the management of this depleted species in the Mediterranean sea.