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 populations studied or a weak a priori definition of the thermal tolerance of this species are discussed.