August 26, 2009

Fish farms can harm more than salmon

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Vancouverites are protesting a new fish farm amid concerns about local salmon declines, reports Wendy Stueck of the Globe and Mail. The proposed site for the Gunner Point fish farm is in Johnstone Strait, an area opponents say young salmon would be forced to pass on their way to the ocean. Being funneled past the farm could expose juvenile salmon to sea lice and disease.

Grieg Seafood, the company proposing the facility, has offered to time production schedules to minimize sea lice spreading, as well as to complete more monitoring for sea lice than is legally required. It is still waiting for provincial approval to open.

Another fish farm on the northwest tip of Vancouver Island is causing problems even though its production ceased years ago, reports Scott Simpson of the Vancouver Sun. Although the Centre Cove salmon farm was shut down in 2004, new government reports indicate metals released from the farm will have toxic effects on life on the ocean floor for more than a 100-yard radius from the site until 2019.

The main culprits at the site are zinc and copper. Copper was used as an “anti-fouling” agent to keep algae and barnacles from growing on nets (many boats use copper-based paint to prevent growth as well). Zinc was in the food fed to the salmon raised at the farm. The spread of contamination is worse because the site is located in an area where slow ocean currents couldn’t effectively disperse the metals, allowing them to persist and build up in organisms like clams and oysters. Fish farms now are built in areas with stronger currents and higher oxygen levels to minimize such contamination. Surprisingly, sea worms have taken hold in the Centre Cover area despite the toxic metals and appear to be helping recovery efforts.

– Emily Linroth

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