Sjøørret i Trondheimsfjorden; en utdøende ressurs. Hva betyr bekker for sjøørreten?

Sammendrag

Sea migrating trout in Trondheimsfjorden; a resource close to extinction. The sea trout population in the Trondheim fjord has never been lower, and the reason is explained primarily by impact factors in saltwater. Recent electrofishing studies of sea trout streams in Trondheim and Trøndelag, with enhanced focus on hydromorphological factors compared to earlier, highlights an extensive loss of stream habitat, habitat quality and water quality in typical sea trout streams. Many studies show that the same problem also extends to other regions of Norway. Freshwater factors are contributing to the decline of sea trout populations observed from Trøndelag in the north to the Oslo Fjord in the south, but the full extent is still unknown. These freshwater factors must be included in the risk assessments and management of Norwegian sea trout populations. Implementation of the Water Frame Directive (WFD) in Norwegian water management means that all impact factors in Norwegian rivers and streams must be included, also hydromorphological. Further work with the WFD in Norway must able us to obtain this information for sea trout streams.