Menu C. auteur aut IRD Pecquerie Laure auteur aut IRD Bacher C. auteur aut IRD Doray M. auteur aut IRD Hattab T. auteur aut IRD van der Kooij J. auteur aut IRD Huret M. auteur aut IRD text journalArticle eng text/pdf born digital access Small pelagic fish have shown a general decrease in size and body condition over the past two decades in several European regional seas. Although the underlying processes are still not well understood, recent studies point to a bottom-up control. In order to better understand how the environment impacts the main individual life history traits, which themselves control the dynamic of the population, we developed a comparative approach between two species, European anchovy and sardine, and across three regions of the Northeast Atlantic and Mediterra-nean Sea: the English Channel in the north, to the Bay of Biscay and the Gulf of Lion in the south. We developed a bioenergetic modeling framework based on the Dynamic Energy Budget theory (DEB). Our DEB models were forced using two different representations of the lower trophic levels, POLCOMS-ERSEM and SEAPODYM models. Our models were calibrated for the Bay of Biscay and then projected on to the other regions, over the early 2000s (period with bigger fish) and the early 2010s (period with smaller fish). The environment alone, temperature and zooplankton, explained a significant part of the observed regional differences in growth. However, the temporal trends simulated by the lower trophic levels models, when transcribed through bio-energetics, could not explain the strong decrease in length and weight that occurred in the Bay of Biscay (-30 % in weight for anchovy and-20 % for sardine) and in the Gulf of Lion (-30 % for anchovy and-50 % for sardine). Through a scenario approach, we estimated that a decrease in zooplankton quality could be a significant driver of the observed decrease in size both in the Bay of Biscay and in the Gulf of Lion (decrease in assimilable energy of 4 to 5 % and 15 to 17 % in the Bay of Biscay and the Gulf of Lion, respectively). For such a decrease in size, a zooplankton biomass of the same quality should have been reduced by between 17 and 31 % in the Bay of Biscay over a 10-to 15-year period, while no biologically realistic estimations were obtained for the Gulf of Lion. The validity of these proposed changes in biomass and quality is discussed in context of alternative explanations. specialized Pelagic environment Bioenergetics Life history traits Small pelagic fish Zooplankton English Channel Bay of Biscay Gulf of Lion EUROPE ATLANTIQUE MEDITERRANEE 034 040 210 102943 [20 ] 2023 0079-6611 https://www.documentation.ird.fr/hor/fdi:010087578 10.1016/j.pocean.2022.102943 0079-6611 [F B010087578] https://www.documentation.ird.fr/hor/fdi:010087578 https://www.documentation.ird.fr/intranet/publi/2023-05/010087578.pdf Accès réservé (Intranet de l'IRD) IRD - Base Horizon / Pleins textes 2023-05-12 2026-06-12 fdi:010087578 fre