Threats: Aquaculture

Publication - April 8, 2008
Aquaculture as it is currently practiced is not the answer to depleted wild fish stocks. On the contrary, the booming global aquaculture industry is seriously threatening marine and freshwater ecosystems and undermining food security across the planet.

As wild fish stocks continue to decline, the demand for farmed shrimp, salmon, tuna, tilapia and other finfish has risen. Aquaculture, one of the fastest growing sectors of the food industry, already provides nearly half of all fish consumed by people. In 2005, global production of marine aquaculture totalled 18.9 million tonnes and freshwater production totalled 28.9 million tonnes. But the growing demand for cheap, abundant seafood has come at a hefty price. Harmful environmental and social impacts of aquaculture include destruction of habitat, the effects of escaped farm fish on wild species, depletion of wild stock caught for feed, disruption to the natural food chain and the threat to food security.

Social impacts associated with aquaculture are being felt around the globe. In Sri Lanka, 74 per cent of those who live in coastal shrimp farming areas no longer have readily accessible drinking water due to the depletion and salinity of potable water. In Chile, the working conditions in the bourgeoning salmon farming industry are so unsafe that in the past three years alone they have resulted in 50 deaths, accusations of sexual harassment of women, and long hours with wages at the poverty line. Human rights abuses plague shrimp farms in many countries. Cases of abuse have been reported in 11 countries and in Bangladesh alone an estimated 150 murders have been linked to aquaculture.

Canada is also suffering from many of these serious environmental impacts. With aquaculture quadrupling both in volume and value in the last 15 years, our marine waters and species are facing increasing problems. For example, recent research in British Columbia suggests that infestations and transfer of sea lice originating from salmon farms, will cause wild pink salmon populations in the Broughton Archipelago to fall by 99 per cent within the next four generations. Nutrient pollution from fecal matter and wasted feed also has a devastating impact on whole ecosystems in Canada. A salmon farm of 200,000 fish releases roughly the same amount of fecal matter as the untreated sewage of 65,000 people. Many salmon farms in the Pacific Northwest have four to five times that number of fish.  Because few species can survive the oxygen-deprived environment created by waste feed and feces, biodiversity in such areas has decreased. Research near finfish farms in the Bay of Fundy found that diversity decreased significantly up to 200 metres away from the cages after five years of operation.

Aquaculture is also taking its toll on Canada’s marine species in other ways. Predator deterrent devices and operational equipment have been found to injure and exclude marine species from their habitat and traditional fishing grounds have been displaced as farms are located in critical fish habitat such as spawning grounds, migration routes and nurseries. Traditional fishing has been completely excluded from the L’etang inlet in the Bay of Fundy, and the Bay contains highest concentration of salmon farms in the World.

Greenpeace Canada is calling for a moratorium on new site approvals as well as increases in production for open net pen finfish operations, a decrease in current production levels and a move to closed containment systems within Canadian waters. Greenpeace believes that closed containment operations, shellfish aquaculture and industrial fisheries can only be sustainable if a truly ecosystem-based management approach is taken, within the framework of a global network of fully protected marine reserves covering 40 per cent of the oceans. The aquaculture report presents more detailed recommendations for industry to follow to move towards sustainability.