Do northern riverine anadromous Arctic charr<i>Salvelinus alpinus</i>and sea trout<i>Salmo trutta</i>overwinter in estuarine and marine waters?

Abstract

By use of acoustic telemetry, the present study showed that both riverine anadromous brown trout (sea trout) Salmo trutta and Arctic charr Salvelinus alpinus in a north Norwegian river descended the river within the first 4 months after spawning in late September and spent long parts of the remaining winter period in the estuary and also possibly partly in salt water. This contradicts the general assumption, based on studies of lake‐dwelling populations, that both species, and in particular S . alpinus , overwinter and spend 9–11 months in fresh water at northern latitudes and the rest of the year in salt water.