Étude de cas sur les impactsBritish Columbia (Canada) Compétition: Salmo salar displays significant niche overlap with juvenile steelhead rainbow trout Oncorhynchus mykiss and, under limiting circumstances, are likely to come into vigorous competition for resources (Volpe et al, 2001). New Brunswick (Canada) Menace pour les espèces en danger: Cultured Salmo salar populations have dominated locations in New Brunswick, specifically the Bay of Fundy. Corresponding with increased fish farming between 1983 to 1997, escaped cultivated S. salar have gone from comprising only 5.5% of the Atlantic salmon population to the majority in the Magaguadavic River by means of hybridization and competition. This significant decline in wild populations of S. salar have caused the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) to classify it as an endangered species (Carr et al, 1997; Dextrase & Mandrak, 2006). Norway Compétition: Escaped Salmo salar from Norwegian fish farms has varied between approximately 250,000 and approximately 600,000 individuals yearly since 1994. These escapees threaten wild populations through competition (Fiske, 2006). Hybridation: Escaped Salmo salar from Norwegian fish farms threaten wild populations through hybridization (Fiske, 2006). Northern Ireland (United Kingdom (UK)) Compétition: Adult farmed Salmo salar escapees are less successful at reproducing in the wild but their offspring are highly sexually precocious, outcompeting native salmon in river environments (Stokes et al, 2006). Scotland (United Kingdom (UK)) Transmission de maladie: Farmed populations of Salmo salar have been found to transmit sea lice (Lepeophtheirus salmonis) to wild salmon populations in Scotland ( Amundrud & Murray, 2009). S. salar smolts transported from Scotland to Norwegian fish farms in the 1980's were infected with furunculosis a disease caused by the bacterium Aeromonas salmonicida. The disease spread rapidly and over 250,000 escaped farmed Atlantic salmon were infected with it spreading furunculosis to wild populaitons (Naylor et al, 2005). Washington (United States (USA)) Transmission de maladie: Infected Salmo salar cultivated in the Puget Sound have introduced viral hemorraghic septicema (VHS) to the west coast (Fuller, 2009).
|