The effect of warming on the bioenergetics of juvenile common sole (Solea solea) in the Gironde estuary: Implications for abundance and life-history traits in an energy-limited nursery ground

Among human-induced environmental changes, increasing water temperature is one of the most well-documented consequences of climate change, and is likely to influence the nursery function of estuarine environments. However, our ability to assess these effects remains limited at the individual level, and mechanistic models applicable at the population level are still lacking. To investigate the specific effects of temperature on the individual life-history traits of juvenile common soles ( Solea solea ) in the Gironde estuary we employed a bioenergetic model based on Dynamic Energy Budget (DEB) theory. Assuming that the estuary has reached its maximum trophic carrying capacity, these effects were also evaluated under two conditions of limited energy availability (applied either globally on the available food, increasing competition, or equally on all juvenile), using temperature projections based on IPCC scenarios. At the individual scale, when energy limitation is caused by unlimited individual feeding, our model predicts that sole will grow more rapidly and reach sexual maturity earlier with increasing temperature, as they remain below their thermal optimum. This scenario implies increased individual energetic demand which can be sustained only with a reduced number of juveniles in the estuary in a context of limited food. Conversely, when energy limitation is equally distributed across all juveniles of the estuary, no significant changes in growth or maturation (i.e., age and length at maturity) are predicted with increasing temperatures; however, our model also predicts a reduction in energy reserves, potentially altering responses to other environmental changes.