Agri. & Environ.
Salmon fish farms pollute wild fish
By Ben Wasserman
Apr 21, 2006, 13:03

April 21 (foodconsumer.org) - Wild fish is viewed to be less polluted than farm raised fish. But a new study has found that wild fish living near salmon fish farms contains elevated levels of mercury, a nervous poisoning.

The study published April 19 on Environmental Science & Technology Research ASAP website (DOI: 10.1021/es0520161) found that wild fish near salmon pens had twice as much mercury in their flesh as those caught in three reference locations where there are no salmon pens.

Researchers theorized that the feed leftover and feces released from the cages would be picked by hungry invertebrates, which in turn attract predators such as rockfish that swim in for the feast. Ultimately, this would change the ecosystem, promoting formation of methylmercury polluting wild fish.

Previous studies found that farm raised salmon contains up to seven times higher levels of PCB than wild salmon fish. Also, research has found that the salmon fish farms can increase the levels of PCB in wild fish.

Wild fish is not necessarily cleaner. Fish consumers should be aware that fish caught in lakes and rivers, even if they are wild, can carry sizable amounts of all types of pollutants. The Environmental Protection Agency data indicate that those wild fish can harbor high levels of dioxin, another cancer-causing toxin commonly found in the environment.

Those who enjoy local fish should read their state¡¯s fish consumption advisory which specifies which fish caught from where can be consumed.


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