Physiological and adaptive responses of fish to ocean acidification


Prof. Guy Claireaux

Project type



Fondation pour la Recherche sur la Biodiversité

Ministère de la Transition Ecologique et Solidaire

Project duration

Start Date

January 1, 2018

End Date

December 31, 2020


The increase in atmospheric CO2 emissions and their absorption by the oceans leads to a decrease in pH in marine waters. This ocean acidification (OA) is likely to affect the functioning of marine ecosystems and endanger their species. The scientific community has been rapidly mobilized and has made significant progress in understanding biological responses to AO, targeting a small number of species. However, despite their economic, ecological and heritage importance, there are very few studies that have considered fish as a case study. In addition, the results obtained are often of too limited ecological significance to conclude about the ability of a fish stock or species to respond (plasticity) or adapt (genetic, epigenetic) to the AO. Yet assessing the fish’s ability to respond to AO is crucial, not only because these organisms are a major component of marine ecosystems, but also because they are essential for human prosperity and food. Globally, the fisheries and aquaculture sectors employ 55 million people, who provide about 15% of their animal protein needs to nearly 4.5 billion consumers.

It is in this context that we aimed to

– Study 2 scenarios of ocean acidification evolution, projected for 2050 (pCO2=800µatm, pH=7.8) and for 2100 (pCO2=1200µatm, pH=7.6)

– Test the physiological responses implemented by a species of fisheries and aquaculture interest, the European sea bass (Dicentrarchus labrax) throughout its life cycle

In 2013, the FITNESS project (collaboration with Germany, the University of Hamburg and the Alfred Wegener Institute (AWI)) was initiated, exposing larvae as early as their hatching to the 2 scenarios mentioned above.

In 2017, the larvae became adult sea bass, beginning their sexual maturation. The PACIO project will be able to initiate for the first time studies on the transgenerational effects of acidification on a long lifecycle fish. It should also be noted that PACIO will combine acidification and ocean warming, taking into account two temperatures, 15° and 20°C.