Density-dependent refuge use among over-wintering wild Atlantic salmon juveniles

Sheltering behaviour of wild juvenile Atlantic salmon in an indoor stream was found to be density dependent; the proportion of fish sheltering decreased significantly with increasing population density. The mean number of fish occupying refugia was ≤1.5 fish per refuge even at very high densities (potentially 5 fish per shelter). These results suggest that shelter availability has potentially important consequences for the carrying capacity for natural populations of salmon in streams