Common-garden comparison of relative survival and fitness-related traits of wild, farm, and hybrid Atlantic salmon Salmo salar parr in nature

When escapee farmed Atlantic salmon Salmo salar interbreed with wild fish, the introgression of maladaptive genes can lower population productivity and alter key life history traits. To date, only a few European studies have compared wild, farm, hybrid under common conditions in isolating influence genetics on survival fitness-related Here, we examined performance experimentally derived fry from 4 cross types (wild, reciprocal F 1 hybrids) during first summer growth at 3 locations southern Newfoundland. Overall was high, type rank order consistent across sites (mean percent recaptured: wild-mother hybrids 26.2% ≈ 26.0% > farm 19.2% farm-mother 12.8%). Wild fish were smaller than though differed less size hybrids. At 2 out sites, larger but had small advantage over fish. Shape differences mainly related to body depth, largest between Wild-mother fewer parr marks other single site, minimal, tended narrowest marks. Overall, these results show that genetic exist for traits among juveniles, even short temporal scales favourable environmental conditions, may contribute patterns reduced feral wild.