Fish adaptation to freshwater hypoxia: developmental, transgenerational and evolutionary potential

Hypoxia (i.e. condition of low oxygen dissolved) represents one of the most important challenges for freshwater ecosystems. While hypoxia events occur naturally, human activities have exacerbated their strength and temporal fluctuations. The possible adaptation to hypoxia events is likely to happen at different time scale. When directly exposed, organism may be able to adjust their phenotypes through phenotypic plasticity. However, continued responses to ongoing hypoxia change will depend on the phenotypic evolution of the species. In addition, some non-genetic transgenerational effects may also occur to facilitate evolution. It is thus essential to document all these type of responses to have a better understanding of the potential response of populations to changing environments. Therefore, the main aims of this project are: 1) to determine how hypoxic conditions may affect the plastic response (morphology, physiology, behaviour) of a fish species (three-spined sticklebacks, Gasterosteus aculeatus) within a generation, 2) to document phenotypic and genetic differences in populations of sticklebacks with different historical levels of hypoxia conditions, and 3) to investigate the occurrence of non-genetic transgenerational effects across generations. This project will use an innovative approach to investigate the mechanisms underlying fish response to environmental change as it will integrate the effects of plasticity, evolution and non-genetic transgenerational effects.