Food availability modulates the combined effects of ocean acidification and warming on fish growth

• Published in: Scientific Reports
• Main Authors: Cominassi, Louise, Moyano, Marta, Claireaux, Guy, Howald, Sarah, Mark, Felix C., Zambonino-Infante, Jose-Luis, Peck, Myron A.
• Other Authors: Center for Earth System Research and Sustainability (CEN), Universität Hamburg (UHH), Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Alfred Wegener Institute for Polar and Marine Research (AWI), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2020
• Subjects: ACL; panorama; INTESTINAL ALKALINE-PHOSPHATASE; EUROPEAN SEA-BASS; DICENTRARCHUS-LABRAX LARVAE; EARLY-LIFE STAGES; CONVERSION EFFICIENCY; MULTIPLE STRESSORS; DIGESTIVE ENZYMES; FORAGING BEHAVIOR; CLIMATE-CHANGE; CARBONIC-ACID; [SDE.BE]Environmental Sciences/Biodiversity and Ecology; Carbonic acid; Ocean acidification
• Online Access: https://hal.science/hal-02921201; https://hal.science/hal-02921201/document; https://hal.science/hal-02921201/file/s41598-020-58846-2.pdf; https://doi.org/10.1038/s41598-020-58846-2

International audience When organisms are unable to feed ad libitum they may be more susceptible to negative effects of environmental stressors such as ocean acidification and warming (OAW). We reared sea bass (Dicentrarchus labrax) at 15 or 20 °C and at ambient or high PCO2 (650 versus 1750 µatm PCO2; pH = 8.1 or 7.6) at ad libitum feeding and observed no discernible effect of PCO2 on the size-at-age of juveniles after 277 (20 °C) and 367 (15 °C) days. Feeding trials were then conducted including a restricted ration (25% ad libitum). At 15 °C, growth rate increased with ration but was unaffected by PCO2. At 20 °C, acidification and warming acted antagonistically and low feeding level enhanced PCO2 effects. Differences in growth were not merely a consequence of lower food intake but also linked to changes in digestive efficiency. The specific activity of digestive enzymes (amylase, trypsin, phosphatase alkaline and aminopeptidase N) at 20 °C was lower at the higher PCO2 level. Our study highlights the importance of incorporating restricted feeding into experimental designs examining OAW and suggests that ad libitum feeding used in the majority of the studies to date may not have been suitable to detect impacts of ecological significance.