Dramatic declines in wild salmon populations are associated with exposure to farmed salmon

Feb 12, 2008
Atlantic Salmon
A global survey of wild salmon and trout populations reveals substantially reduced survival among those populations that migrate past salmon farms as juveniles on their way to the ocean. Credit: United States Fish and Wildlife Service

Since the late 1970s, salmon aquaculture has grown into a global industry, producing over 1 million tons of salmon per year. However, this solution to globally declining fish stocks has come under increasing fire. In a new study published this week in the open-access journal PLoS Biology, Jennifer Ford and Ransom Myers provide the first evidence on a global scale illustrating systematic declines in wild salmon populations that come into contact with farmed salmon.

Previous studies have clearly shown that escaped farm salmon breed with wild populations to the detriment of the wild stocks, and that diseases and parasites are passed from farm to wild salmon.

However, until now, there has been no assessment of the importance of these impacts at the population level and across the globe. Here, Ford & Myers compared the survival of salmon and trout that swim past salmon farms to the survival of those fish that never pass a salmon farm.

In five regions around the world, Ford and Myers find a significant decline in the survival of wild salmon populations that are exposed to salmon farms. This decline took place as farmed salmon production increased in each region. Combining these regional estimates, the authors find that wild populations suffer a reduction in survival or abundance of more than 50% when associated with farmed salmon.

These new results suggest that salmon farming could seriously compromise the persistence of the world’s salmonid populations.

Citation: Ford JS, Myers RA (2008) A global assessment of salmon aquaculture impacts on wild salmonids. PLoS Biol 6(2): e33. doi:10.1371/journal.pbio.0060033

Source: Public Library of Science

Explore further: 'Tiger heavyweight' Nepal hosts anti-poaching summit

add to favorites email to friend print save as pdf

Related Stories

Surrogate sushi: Japan biotech for bluefin tuna

Nov 20, 2014

Of all the overfished fish in the seas, luscious, fatty bluefin tuna are among the most threatened. Marine scientist Goro Yamazaki, who is known in this seaside community as "Young Mr. Fish," is working to ...

Hatchery fish mask the decline of wild salmon populations

Feb 08, 2012

Scientists have found that only about ten percent of the fall-run Chinook salmon spawning in California's Mokelumne River are naturally produced wild salmon. A massive influx of hatchery-raised fish that return to spawn in ...

Recommended for you

'Tiger heavyweight' Nepal hosts anti-poaching summit

10 hours ago

Nepal's success in turning tiger-fearing villagers into their protectors has seen none of the endangered cats killed for almost three years, offering key lessons for an anti-poaching summit opening in Kathmandu ...

GMO mosquito plan sparks outcry in Florida

Jan 31, 2015

A British company's plan to unleash hordes of genetically modified mosquitoes in Florida to reduce the threat of dengue fever and other diseases has sparked an outcry from fearful residents.

Population genomics unveil seahorse domain

Jan 30, 2015

In a finding vital to effective species management, a team including City College of New York biologists has determined that the lined seahorse (Hippocampus erectus) is more a permanent resident of the we ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.