Landlocked Salmon and Trout in the Lake Vänern-River Klarälven ecosystem – What can we do for the wild fish?

Abstract

Populations of migratory salmon and trout have worldwide shown a decline due to human activities. Over the years numerous measures have been undertaken to maintain these populations, and conservation of migratory salmonids requires understanding of their ecology at multiple scales, combined with assessing anthropogenic impacts. The regulated River Klarälven and Lake Vänern host endemic populations of landlocked Atlantic salmon (Salmo salar) and brown trout (Salmo trutta). The historically high abundances of the salmonids in the River Klarälven in the early 1800s have decreased dramatically, reaching all-time lows after the completion of all nine Swedish hydroelectric power stations in the 1960s. After an extensive stocking program and transportation of spawners past eight hydroelectric plants, catches from commercial, maintenance and sport fishing have again increased (1). Recently, increases in the proportion of wild salmon returning to the River Klarälven have generated interest in establishment of wild salmon inhabiting the entire River Klarälven, including upstream of the Norwegian border. How well are we equipped to meet these new dreams, taking into account our limited knowledge of the species’ different life stages (2), coordination between different actors involved in the conservation processes, and our skills to communicate and understand everybody’s role in this conservation process (3)?

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