The Salmon Files

Salmon Farming Basics

In a nutshell, salmon farming consists of rearing hatchery-bred salmon in floating net pans with controlled feed. In freshwater hatcheries, adult salmon spawn in a controlled environment, and the resulting ferilized eggs are grown out to the juvenile stage called smolt, the stage at which wild salmon migrate to salt water. Smolts are typically stocked by year class in net pens in salt water, where they are fed pelletized feed largely based on fish meal, and grow to market size in one to three years.

Salmon farming technology arose in Norway, as a response to dwindling catches of wild salmon. Although various salmonid species can be farmed, Atlantic salmon (Salmo salar), the single species of salmon native to the north Atlantic rim, has proven the most reliable and economical, and is now farmed in northern Europe, Chile, Tasmania, both coasts of Canada, and the US states of Maine and Washington.

Since its beginning in the 1960s, salmon farming technology has made steady strides in production efficiency. Generations of selective breeding favor strains of fish that grow rapidly. Feed manufacturers, farmers, and academics have worked together on improvements in feed formulation to maximize the digestibility of the feed and provide the optimum blend of nutrients for maximum growth. Even feeding technology has changed; where feeding rates were once calculated guesswork, many farms are now equipped with underwater cameras that monitor the underside of the pens and shut off feeding when uneaten feed falls through the nets (a sign that the fish are temporarily sated). Together, these advances have brought the feed conversion ratio close to 1:1 -- that is, a pound of feed added to a pen results in nearly a pound of fish growth.

With the increases in efficiency as well as a global increase in production, the price of farmed salmon has dropped steadily. At first, farmed salmon was a relatively expensive offseason replacement for wild salmon, sold mainly in the winter months when fresh salmon was unavailable. During the fresh Pacific salmon season, roughly spring to early fall, farmed salmon could not compete in price. By the late 1980s, the price of farmed salmon had declined to that of the wild fish, and as the curves crossed, many buyers opted for the convenience, uniformity, and steady availability of the farmed fish, and it gained a year-round market.

In the 1990s, farmed salmon from various sources, but especially Chile, became a daily staple of fish markets and supermarkets across North America, at prices that were downright cheap compared to many wild fish. In a market that treats salmon as a single commodity, wild salmon has had a tough time competing, with Pacific salmon fishermen routinely settling for prices that would have sent them out on strike twenty years ago.

Not all farmed salmon is Atlantic; some farmers in British Columbia, Chile, and New Zealand continue to raise Pacific king and coho salmon. Another Pacific Coast native, rainbow trout, already one of the most widely introduced and aquacultured freshwater fish in the world, can also be raised in salt water, and when fed the same kind of pigmented feed it grows to a size, appearance, and flavor approaching those of salmon. Saltwater rainbows are variously sold as sea trout, salmon trout, or steelhead.