Salmon Farming
by author The David Suzuki Foundation
Salmon farming - the placement of large metal or mesh net cages in the ocean to grow fish - was pioneered in Norway in the 1960s. Since then the industry has expanded to Scotland, Ireland, Canada, the United States, and Chile, but is dominated by the same multinational corporations.
Wherever it is practised, net-cage salmon farming is controversial and raises serious environmental concerns.
The David Suzuki Foundation does not oppose salmon farming, but is opposed to practices that negatively affect marine and freshwater habitats, wild fish species, and other industries that rely on a healthy marine environment like tourism, sports and commercial fishing.
Summary of Problems
Since the 1980s, aquaculture-the aquatic version of industrial agriculture-has been the fastest-growing supplier of fish worldwide. Some observers see aquaculture as an opportunity to take the pressure off wild fish stocks, while addressing the growing imbalance between fish production and food requirements for an expanding world population. While aquaculture can be beneficial in some cases, this is not the case when carnivorous species are farmed.
Salmon are carnivores. So besides the ecological and health concerns associated with salmon farming, farmed salmon actually represent a “net loss” of protein in the global food supply as it takes from two to five kilos of wild fish to grow one kilo of salmon. Highly nutritious fish like herring, mackerel, sardines, and anchovy are used to produce the feed for farmed salmon, which is essentially luxury fare for the North American, European and Japanese markets.
The vast majority of global aquaculture production, about 85 percent, uses non-carnivorous fish species - like tilapia and catfish - produced in land-based ponds for domestic markets. Most ponds are ecologically integrated into the agricultural, industrial, and community fabric, meaning, for example, that wastes become fertilizers rather than pollutants.
Instead of net cages, the David Suzuki Foundation believes that the salmon farming industry must be transformed to use safe, fully enclosed systems that trap wastes. Farmed salmon feed often contains antibiotics, other drugs, and pesticides, and excess feed and feces smother the ocean floor beneath and around the net cages, causing significant habitat damage. Fish escapement and the transfer of disease from farms to the marine environment are other serious concerns. In British Columbia, it is estimated that well over one million fish have escaped from net cages since the early 1980s.
A unique problem caused by the British Columbia industry is the introduction of a non-native species - Atlantic salmon - into the Pacific Ocean. The United Nations has declared that the introduction of exotic - or alien- species is the greatest threat to global biodiversity after habitat loss. So why Atlantic salmon in the Pacific? It all goes back to Norway where the industry was born, and an expansion of Norwegian interests into BC in the early 1980s.
Norway was the world leader in farmed salmon production and created markets that previously did not exist using Atlantic salmon. Therefore, Atlantic salmon became the favoured farmed variety, and with decades of experience culturing Atlantics, Norwegian companies decided to introduce the foreign species instead of starting anew in BC with Pacific stocks. These companies had invested heavily in developing markets for Atlantic salmon and products from Pacific stocks did not easily fit into this marketing strategy. Also, Atlantic salmon convert feed to meat more efficiently and are less aggressive - leading to greater growth and lower mortality than chinook or coho salmon, two species farmed in BC's nascent domestic industry.
Worldwide, the salmon net-cage industry uses publicly owned coastal waters to support what are essentially intensive private feedlot operations that dump drug-laced sewage into the ocean. Governments looking for new opportunities in rural, economically depressed coastal areas often have encouraged the industry. But increasingly, citizens are questioning if any benefits are offset by the alarming array of environmental, social, economic, and health costs.
Recent research has focussed on the health differences between wild and farmed salmon. A pilot study by the Suzuki Foundation was one of the first examinations of this issue, and we will soon issue a new report looking at the difference in quality of omega-3 fatty acids found in wild and farmed salmon.
Problems Associated With Salmon Farming Practices
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Sewage from farms pollutes surrounding waters.
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Drugs are required to keep farmed fish healthy.
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Escapes of farmed fish threaten native wild fish.
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Net Loss: Salmon farming depletes other fish species.
“Normal” livestock and poultry are routinely pumped full of hormones. This isn’t going to impact the general public’s exogenous hormone consumption at all.