Description of the monthly spatial dynamics of commercial and bycatch demersal species in the Bay of Biscay.

The global environmental crisis challenges the sustainable management of marine resources, with declining fish stocks threatening both livelihoods and biodiversity. In multi-species fisheries, non-selective fishing gear often results in the capture of non-target species (bycatch), including those subjects to catch limits under the European Union's landing obligation. This regulation introduced the concept of 'choke species': species whose quota is reached but that continue to be caught incidentally, forcing fishing to stop-even if other quotas are still available. In the Bay of Biscay mixed demersal fishery, such technical interactions are linked to combination of targeted species - such as sole (Solea solea), megrim (Lepidorhombus whiffiagonis) and white anglerfish (Lophius piscatorius) - and less targeted or non-target species such as thornback and cuckoo rays (Raja clavata, Leucoraja naevus). To inform these complex interactions, we provide datasets for these five key demersal species including: (1) high-resolution spatial distribution maps of juvenile and adult stages; (2) comprehensive life-history parameter summaries incorporating uncertainty; and (3) structured data designed for integration into spatially explicit models.