Arroyo N. L. auteur aut IRD Safi G. auteur aut IRD Vouriot P. auteur aut IRD Lopez-Lopez L. auteur aut IRD Niquil N. auteur aut IRD Le Loc'h François auteur aut IRD Hattab T. auteur aut IRD Preciado I. auteur aut IRD text journalArticle eng text/pdf born digital access Using the Bay of Biscay (BoB) as a case study, we conducted a transnational assessment of the mean trophic level (MTL, Ospar FW4) indicator at sub-regional level, over the last three decades. Our results confirm the apparent recovery of BoB's bentho-demersal system, as shown by trends in the MTL indicator based on survey data. However, they also point at a concomitant "fishing through" process where the apparent stability revealed by the MTL indicator based on landed catch data may be masking the expansion of demersal fisheries to deeper waters, and an over-exploitation of resources (particularly abundant pelagic species). Moreover, they show how the combined examination of independent surveys and fishery landings allows the identification of ecological trends in ecosystem studies. In addition, our results confirm that analysing MTL at various threshold levels helps discerning the causality of trends in this indicator, especially if analyses for pelagic and demersal species are run independently. Further studies, at smaller (i.e. local) spatial scales, need to be conducted to ascertain our results and suggest appropriate management strategies aimed at regulating fisheries expansions in the area. specialized Bay of Biscay ecology environmental status fisheries expansion fishing through food webs mean trophic level MSFD OSPAR indicators ATLANTIQUE BISCAYE BAIE 036 040 76 6 1543-1553 2019 1054-3139 https://www.documentation.ird.fr/hor/fdi:010077432 10.1093/icesjms/fsz023 1054-3139 [F B010077432] https://www.documentation.ird.fr/hor/fdi:010077432 https://www.documentation.ird.fr/intranet/publi/2020/01/010077432.pdf Accès réservé (Intranet de l'IRD) IRD - Base Horizon / Pleins textes 2020-02-05 2025-02-24 fdi:010077432 fre