February 13, 2008

Global study finds harmful effects of fish farms on wild salmon populations
 

Wild salmon populations generally decline in rivers where fish farms exist, according to the first global assessment of aquaculture's effect on wild salmon.

The study was funded by Lenfest Ocean Program, and was published this week in a peer-reviewed open-access online journal, PloS Biology, produced by the Public Library of Science.

The study discovers that in rivers where young salmon passed by fish farms during migration, the number of them surviving and returning to reproduce are decreased by 50 percent or greater on average, as when compared to similar rivers with no fish farms.

Jennifer Ford, lead author of the study said the findings from their analyses varied in different regions but upon combination, they see a startling and significant negative impact on wild salmon.

John Reynolds of Vancouver's Simon Fraser University, said salmon farming as currently practised is incompatible with sustainability of healthy wild populations.

Scientists analysed data from rivers on the Atlantic and Pacific Coasts of Canada and the UK. Researchers chose rivers with fish farms and nearby rivers of comparable climate and without fish farms.

Margaret Bowman, director of the Lenfest Ocean Program, said a cautious observation of the link between fish farms and declining wild salmon populations is required, especially in areas where wild salmon are low in numbers.

Ford concluded that while the reason for suffering wild salmon populations may vary from place to place, but aquaculture does present various factors that reduce the survival of wild salmon.