Environmental impacts: Open net-pen salmon farms benefit from the ocean but the ocean doesn’t benefit from salmon farms
Open net-pen salmon farms are located in areas along the coast where they can take advantage of ocean currents to deliver oxygen to their fish and disperse their wastes -- all at no cost to the industry. But there are costs to the ocean from these operations that extend from the surface to the seabed. The waste products (faeces and feed) from the farmed salmon in the pens are released directly into the surrounding water and settle to the sea floor. These wastes can change the chemical make-up and biological diversity of the seabed around the pens. Wild rockfish that congregate near salmon farms have been found to have higher levels of mercury than their relatives away from the farms.First Nations report impacts on their traditional harvesting areas near salmon farms as clam beaches are covered with reeking sludge, the clams blackened and inedible. Fishermen report lower catches of some species in areas near open net-pen salmon farms.