Ocean Matters

Introduction to Salmon Farming in British Columbia

Salmon farming is in the news a lot these days, with scientists, First Nations, non-governmental organizations, industry, government decision makers, and even retail food companies all having an important stake in it’s future. While salmon farming makes significant contributions to the economies of British Columbia and Canada, critics are quick to site numerous environmental concerns.  We briefly examine the benefits and concerns associated with salmon farming in B.C.  We also discuss solutions to some of the problems.

Economic Benefits

The first salmon farm in B.C. began operation in 1971.   Since then, salmon farming has become the fastest-growing supplier of fish in the world, with Norway, Chile, the United Kingdom and Canada leading the way in terms of production.  Salmon farms in the province are primarily located in and around the northeast and west coasts of Vancouver Island.  With more than 90% of the industry’s jobs located outside of the large urban centers of Vancouver and Victoria, salmon farms help to diversify B.C.’s coastal communities. In 2006, the B.C. salmon aquaculture sector produced more than 78,000 metric tons of farmed salmon, with harvest sales generating $407 million in farm-gate value.

Environmental Concerns

Despite these clear economic benefits, there are serious environmental concerns associated with the industry.  Problems arise from the fact that most salmon in the province are farmed in open net cages along the coast, sharing water with wild salmon and coastal marine ecosystems.

Non-native Species

Most B.C. salmon farming operations use Atlantic salmon for farming instead of native species (Atlantics makeup approximately 90% of all farmed finfish in the province). Salmon farmers prefer Atlantic salmon as they grow faster than native species such as Chinook and Coho. One of the problems with Atlantic salmon is that they can escape from their ocean pens and live in the wild where they compete directly for food and habitat with B.C.’s native salmon species.  Although the salmon farming industry has made significant improvements, it’s estimated that at least one million fish have escaped from net cages into the oceanic waters of coastal B.C. since the early 1980s.

Sea Lice and Disease

Sea lice and disease emanating from farmed salmon are one of the most serious threats facing wild stocks in the province. Recent evidence suggests that unless extensive changes are made, parasitic sea lice from salmon farms on the west coast of B.C. may help push local wild salmon stocks towards extinction by killing large numbers of juveniles. While adult salmon can generally withstand being infected by sea lice, juveniles, which have thinner skin, are killed by these parasites.  In the past, juvenile wild salmon, which remain near the coast until they head further out to sea as adults, rarely encountered sea lice.   Recent studies, however, have identified open pen salmon farms in coastal B.C. waters as source points for juvenile-infesting sea lice.

Pollution and Drugs

Other problems associated with salmon farming involve water pollution from aquaculture operations. Farmed salmon consume a lot of food and there is some concern that waste emanating from open salmon pens can contaminate surrounding waters. This problem is confounded by the fact that drugs, including antibiotics, are sometimes used to help keep farmed fish healthy.

“Net Loss”

The salmon farming industry has also been critiqued from a sustainability perspective, especially in regards to “net loss.” In conservation biology, net loss occurs when the expense associated with producing a good exceeds its biological return. In the case of salmon farming, food pellets (the expense) made from other fish species are used to feed farmed salmon (the return).  Researchers estimate that it takes between two and three tonnes of wild seafood to produce one tonne of farmed salmon. Thus, some argue that salmon farming is adding to – rather than reducing – pressure on the world’s oceans. Moreover, the energetic and environmental costs associated with fishing, producing, packaging and shipping feed pellets translates into a large ecological footprint for the salmon farming industry.  

Potential Solutions

Many people are proposing that the industry move towards implementing closed tank technologies, believing that they would help reduce and/or eliminate some of the negative impacts of salmon farming.  Physically separating salmon from their external environment, closed farm containers can help prevent the transmission of diseases and parasites and reduce the number of escapees.  Wastes could be treated before they enter the ocean environment.  Closed tanks are also thought to require fewer chemicals and feed, lowering pressure on wild fish used in pellets.
Closed tank technologies are currently used to grow many types of seafood on a commercial scale, including arctic char and trout.  Ongoing research in B.C. suggests that closed tanks provide a feasible salmon farming alternative, with commercial-scale trials currently in the implementation stage.  With the endorsement of NGOs, some farming companies are even building closed pens on dry land, with sea water constantly pumped into them.

Many companies are reluctant to switch to closed container systems because they are more costly to build then conventional open pen salmon farms.  As technology continues to advance, however, closed pen farms are likely to become a more financially viable option.  Furthermore, as public awareness grows, consumers may be willing to pay a little bit extra for a product that is more environmentally sustainable.

As it stands now, salmon farms contribute a lot of money to the B.C. economy.  Although many changes are needed, using new technology and wise, science-based management, it may be possible to keep salmon farms profitable while protecting and conserving wild salmon and their fragile ocean ecosystems.

For more information go to:

The David Suzuki Foundation (NGO perspective)

The British Columbia Salmon Farmers Association
(Industry perspective)

Government of British Columbia (Provincial government perspective)

Georgia Strait Alliance (NGO perspective)

Raincoast Conservation Society (NGO perspective)

"Transmission Dynamics of parasitic sea lice from farm to wild salmon" ( PDF) (Krkosek et al. 2005)

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