Postrelease exploration and stress tolerance of landlocked and anadromous Atlantic salmon and their hybrids

Threatened fish populations worldwide are relying on stock supplementation by hatchery-reared fish. Although stocking with non-native may lead to hybridization, thereby disrupting local adaptations, it could also improve the adaptive potential of small increasing variability in essential behavioral traits. In this study, we crossbred critically endangered Finnish landlocked salmon a geographically close Baltic anadromous population compare boldness-related traits among crossing groups. We studied postrelease exploration seminatural streams and tested stress tolerance fish, as reflected their response during swimming trials commencement feeding after trials. experiments, compared different rearing backgrounds gain insight into environmentally induced tolerance. When salmon, showed more active higher The hybrids displayed intermediate behaviors purebred indicating heritability these less variable than maternal strain, but did not find rearing-dependent responses summary, our findings suggest that hybridization help reversing likely domestication-related negative salmon.