Exposure to farmed salmon causes decline in wild salmon populations

Washington, Feb 12 : A new study has revealed that the wild salmon populations worldwide are slowly declining as they come into contact with farmed salmons.

The cause for the decline in survival of the wild salmon population is believed to be due to the fact that the juvenile wild salmon migrate past salmon farms on their way to the ocean.

Salmon aquaculture is an industry, which has grown globally since the late 1970's, producing over 1 million tons of salmon per year. However, it is a solution that is being held responsible for the globally declining fish stocks.

In the new study that was published in the open access journal PLoS Biology, Jennifer Ford and Ransom Myers provided evidence on a global scale, showing systematically the decline in wild salmon populations after they come into contact with farmed salmon.

In the previous studies, it was shown that when the farm salmon breeds with the wild salmon, a great damage was caused to the wild stocks, as diseases and parasites are passed from farm to wild salmon.

However, until now, there has not been any assessment done to check the importance of the impact at the population level and across the globe.

In the study, Jennifer Ford and Ransom Myers compared the survival rate of the salmon and trout that swim past the salmon farms against those that never pass a salmon farm.

Ford and Myers were able to find that in five regions around the world, there was a major decline in the survival of wild salmon populations that were exposed to salmon farms. The decline in wild salmons was more prominent with the increase of farmed salmon production in each region.

The authors, upon combining the regional findings, discovered that the wild populations suffered a reduction in survival or abundance of more than 50pct when they associated with farmed salmon.

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

ANI