Impacts of Long-Term Exposure to Ocean Acidification and Warming on Three-Spined Stickleback ( Gasterosteus aculeatus ) Growth and Reproduction

• Published in: Fishes
• Main Authors: Jimmy Devergne, Véronique Loizeau, Christophe Lebigre, Anne Bado-Nilles, Sophie Collet, Olivier Mouchel, Ugo Iaria, Marie-Madeleine Le Gall, Lauriane Madec, Cyril Turiès, Arianna Servili
• Format: Article in Journal/Newspaper
• Language: English
• Published: MDPI AG 2023
• Subjects: Gasterosteus aculeatus; climate change; life cycle; sexual maturation; long-term acclimation; lipids; Biology (General); QH301-705.5; Genetics; QH426-470; Ocean acidification
• Online Access: https://doi.org/10.3390/fishes8100523; https://doaj.org/article/1e4ce9691faa4eb79bd28af3481d43a4

The warming and acidification of surface waters as predicted by the IPCC leads aquatic species to face major multifaceted changes in their environment. Although teleosts have efficient regulatory systems to cope with these changes, such changes clearly have the potential to impact their physiological functions. Hence, it is crucial to estimate the ability of teleost fishes to cope with multi-stresses to predict how they will deal with future environments. In this context, we investigated the joint effect of warming and acidification on three-spined stickleback ( Gasterosteus aculeatus ) from the juvenile stage to adulthood, focusing on parameters linked to growth, sexual maturation, and reproduction. Juvenile sticklebacks were split in 2 climate scenarios: a “Current” scenario corresponding to the current seasonal physico-chemical parameters of the water of the “Rade de Brest” in France, and a “RCP8.5” scenario with a warming of 3 °C and an acidification of 0.4 pH units. After 7 months, fish in the RCP8.5 scenario reached the same size and mass as those in the Current scenario, but they needed greater amounts of food to reach satiety. Furthermore, the mortality rate over the experiment was higher in the RCP8.5 scenario. Muscle lipid content, an indicator of energy reserves, was lower in females in the RCP8.5 scenario, suggesting an increased need for energy to maintain homeostasis and other physiological functions or a divergence in energy allocation strategy. Moreover, females exhibited lower sexual maturation and egg quality under the RCP8.5 scenario, which could have contributed to the lower fertilisation rate observed. Males were more resilient to the RCP8.5 scenario, exhibiting only a trend for lower kidney somatic index scores. Altogether, these results suggest a delay and/or an inhibition of gametogenesis and maturation in fish in warmed and acidified waters. The analysis of blood sex steroid concentrations, brain gene expression profiles, and physiological indexes did not allow us to discriminate between ...