FN Archimer Export Format PT J TI Changes in foraging mode caused by a decline in prey size have major bioenergetic consequences for a small pelagic fish BT AF Thoral, Elisa Queiros, Quentin Roussel, Dominique Dutto, Gilbert Gasset, Eric McKenzie, David Romestaing, Caroline Fromentin, Jean-Marc Saraux, Claire Teulier, Loïc AS 1:1;2:5;3:1;4:3;5:4;6:5;7:1;8:2;9:2,6;10:1; FF 1:;2:;3:;4:PDG-RBE-MARBEC-LSEA;5:PDG-RBE-MARBEC-LAAAS;6:;7:;8:PDG-RBE-MARBEC;9:PDG-RBE-MARBEC-LHM;10:; C1 Univ Lyon, Université Claude Bernard Lyon 1, CNRS, ENTPE, UMR 5023 LEHNA F‐69622 Villeurbanne ,France MARBEC, Univ Montpellier, CNRS, IFREMER, IRD Sète ,France Ifremer (Institut Français de Recherche pour l’Exploitation de la MER), Laboratoire SEA, Chemin de Maguelonne 34250 Palavas‐Les‐Flots ,France MARBEC, Univ Montpellier, CNRS, IFREMER, IRD Palavas‐Les‐Flots ,France MARBEC, Univ Montpellier, CNRS, IFREMER, IRD Montpellier, France IPHC, UMR7178, Université de Strasbourg, CNRS 67000 Strasbourg ,France C2 UNIV LYON, FRANCE IFREMER, FRANCE IFREMER, FRANCE IFREMER, FRANCE CNRS, FRANCE UNIV STRASBOURG, FRANCE SI PALAVAS SETE SE PDG-RBE-MARBEC-LSEA PDG-RBE-MARBEC-LAAAS PDG-RBE-MARBEC PDG-RBE-MARBEC-LHM UM MARBEC IN WOS Ifremer UMR WOS Cotutelle UMR copubli-france copubli-univ-france IF 5.608 TC 15 UR https://archimer.ifremer.fr/doc/00696/80775/84100.pdf LA English DT Article DE ;bioenergetics;fish shrinking;food restriction;foraging behaviour;mitochondria;red muscle;sardine AB Global warming is causing profound modifications of aquatic ecosystems and one major outcome appears to be a decline in adult size of many fish species. Over the last decade, sardine populations in the Gulf of Lions (NW Mediterranean Sea) have shown severe declines in body size and condition as well as disappearance of the oldest individuals, which could not be related to overfishing, predation pressure or epizootic diseases. In this study, we investigated whether this situation reflects a bottom-up phenomenon caused by reduced size and availability of prey that could lead to energetic constraints. We fed captive sardines with food items of two different sizes eliciting a change in feeding mode (filter-feeding on small items and directly capturing larger ones) at two different rations for several months, and then assessed their muscle bioenergetics to test for changes in cellular function. Feeding on smaller items was associated with a decline in body condition, even at high ration, and almost completely inhibited growth by comparison to sardines fed large items at high ration. Sardines fed on small items presented specific mitochondrial adjustments for energy sparing, indicating a major bioenergetic challenge. Moreover, mitochondria from sardines in poor condition had low basal oxidative activity but high efficiency of ATP production. Notably, when body condition was below a threshold value of 1.07, close to the mean observed in the wild, it was directly correlated with basal mitochondrial activity in muscle. The results show a link between whole-animal condition and cellular bioenergetics in the sardine, and reveal physiological consequences of a shift in feeding mode. They demonstrate that filter-feeding on small prey leads to poor growth, even under abundant food and an increase in the efficiency of ATP production. These findings may partially explain the declines in sardine size and condition observed in the wild. PY 2021 PD OCT SO Journal Of Animal Ecology SN 0021-8790 PU Wiley VL 90 IS 10 UT 000657256700001 BP 2289 EP 2301 DI 10.1111/1365-2656.13535 ID 80775 ER EF