Otolith asymmetry as a proxy of thermal stress in cold water fish: do observations on natural populations of Cottus gobio meet experimental results ?

an increase of water temperature due to global warming is expected to be stressful for many aquatic species such as cold-water fishes. Otolith asymmetry is known to be a proxy of fish stress. However, Cottus gobio linnaeus, 1758 inhabiting potentially stressing (i.e. warm) thermal conditions did not present a higher level of asymmetry in their otoliths than other ones. local adaptations to thermal stress of the different popula- tions studied or a weak a priori definition of the thermal tolerance of this species are discussed.-