Advancing sustainable aquaculture: behavioral insights for climate-change resilient fishes
Résumé
The study by Lagarde et al. (2025) is part of efforts aiming to meet the challenges of adapting livestock farming, and more specifically of aquaculture, to the effects of climate change. In fact, during heat waves, water temperatures rise and oxygen becomes scarce. Fish have to adapt to these conditions of hyperthermia and hypoxia. Studies have already shown that it is possible to genetically improve these resistances in salmonids (e.g. Debes et al., 2021). However, current methods for phenotyping these resistances rely on exposing fish to extreme conditions until they lose equilibrium, which indicates that the animal experiences severe conditions and raises ethical and animal welfare concerns. From the aforementioned, there is then a strong interest in using and identifying less invasive phenotypes, such as behavioural changes, that could serve as indicators of fish responses to hyperthermia and hypoxia. Some behaviours show promise in both wild (Campos et al., 2018) and farmed fish (Van Raaij et al., 1996). A former study by the authors of this manuscript suggests that some of these behaviours are sufficiently heritable to consider applying selection on them (Lagarde et al., 2023). Therefore, the main aim of the present study was to test whether behaviour can be used as an indirect selection criterion to improve the adaptation of rainbow trout to heat waves. To achieve this lofty goal, the responses of different isogenic lines of trout to hyperthermia and hypoxia were investigated using new criteria based on behavioural responses and the reference measure of loss of equilibrium. The results suggest that certain behavioural traits, such as distance travelled and frequency of zone changes, are associated with resistance to these stresses. Moreover, moderate correlations were observed between certain behavioural variables and resistance to hyperthermia. Indeed, lines that were more resistant to hyperthermia had lower distance travelled and frequency of zone changes during the behavioural test. Other significant and positive correlations were observed between acute hypoxia resistance and certain behavioural variables, likely distance travelled, frequency of zone change and percentage of time spent moving. These results pave the way for less invasive methods in assessing hyperthermia and hypoxia resistance based on behavioural observations, which could improve the resistance of farmed fish in response to climate change. The study further allows refining the measurements carried out on candidates for selection in order to improve their welfare during evaluation tests. In conclusion, this study is commendable for its thematic relevance, originality and the potential application of its results to genetic selection of farmed fish.
Domaines
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Evalue 10.24072/pcjournal.555 Autre Lagarde, H., Lallias, D., Phocas, F., Goardon, L., Bideau, M., Guyvarc’h, F., Labbé, L., Dupont-Nivet, M., & Cousin, X. (2025). Screening for links between behaviour and acute hyperthermia and hypoxia resistance in rainbow trout using isogenic lines. Peer Community Journal, 5. https://doi.org/10.24072/pcjournal.555