HEALTHSEA

An integrative approach to assessing the effects of global change on the robustness of European sea bass (Dicentrarchus labrax)

Coordination

David Mazurais

Project type

National

Funding

EST-ANSES

Project duration

Start Date

23/11/2024

End Date

23/11/2024

Links

In light of the primary climate change stressors of warming, acidification, and hypoxia coined as the “deadly trio”, the Healthsea project examines fish physiological response and robustness as a driver of population vulnerability and aquaculture sustainability. Since the effects of realistic scenario combining exposure to these three factors are very scarce, the project will address this gap through a case study on the European sea bass, a valuable fisheries and farming species. Healthsea will replicate in captivity post larval exposure for 18 months to two environmental scenarios: an actual (2023) thermal and acidification scenario and the IPCC scenario SSP2-4.5 by 2100 (Condition pH -0.4 and ambient temperature + 3°C). At 15 months post-hatching, fish will be additionally exposed to a moderate hypoxic episode for three weeks in order to mimic the decrease in oxygenation observed more and more frequently in coastal waters. The fish’s fitness will be examined through an integrative biology approach including mortality rate, growth performance, resistance to pathogen (viral and bacterial) challenges and microbiota and physiological characterization. Special attention will be paid to the endocrine system, which is involved in the regulation of many functions such as growth, sexual maturation, metabolism and stress. Parameters related to the immune defence function and energy metabolism will also be analysed through targeted biochemical/molecular biology methods and/or transcriptomic approaches. From a mechanistic point of view, we hypothesise that the observed phenotypes may result from the environmental factors induced-modification of the fish epigenome. Therefore, global methylation analyses on all the cytosines of the genome will be conducted on methyl-cytosine and its derivatives. Biological data obtained within the Healthsea project offers a detailed assessment of climate change impacts, risks and physiological acclimation of fish, for well-coordinated efforts and interventions for the mitigation and adaptation to the adverse impacts of climate change on the coastal ecosystem.