Salmon farming may be a good idea after all | Science Matters | David Suzuki Foundation
Photo: Salmon farming may be a good idea after all

Salmon farming may be our only option — and new technology offers some hope that we can continue to have our salmon and eat it too (Credit: Mary via Flickr).

By David Suzuki with Faisal Moola

It would be a shame if we could never eat salmon again. On the Pacific Coast, salmon has been an important food source and a cultural icon throughout history. Salmon is a healthy, delicious, and versatile source of nutrition. But many wild salmon populations are in trouble and could be facing the same fate as East Coast cod stocks.

Is the answer to raise salmon on farms? The controversy over farmed versus wild salmon has been ongoing in B.C. since the first salmon farms were built in the early 1980s. A growing body of evidence has shown that fish farms that use open-net pens in the ocean can harm wild stocks. Some of the dangers include escaped farmed fish — which are mostly Atlantic salmon — competing with the five species of wild Pacific salmon, pollution from the farms harming the areas where salmon live and migrate, and lice infestations threatening the very survival of some stocks. It's a trade-off that doesn't make much sense.

It would be ideal if we could move these farms and protect our wild stocks to ensure they provide us with food well into the future. But wild salmon face many other threats, including overfishing, habitat loss, and climate change, and we don't yet understand all the factors contributing to their decline.

Farming may be our only option — and new technology offers some hope that we can continue to have our salmon and eat it too. Raising salmon in a way that eliminates interaction with the environments where wild salmon live has long been suggested as a way to overcome the worst effects of farming fish. Despite resistance from some people in the fish-farming industry and government, who argue that contained farming is too expensive, closed-containment salmon farming is becoming a reality.

Early attempts at salmon farming that keeps the farmed fish separate from the wild environment were mostly experimental or too small to be commercially viable. But now a Washington State company, Domsea Farms, is raising sufficient quantities of coho salmon for Canadian grocery chain Overwaitea Food Group to offer the company's SweetSpring salmon in its 124 stores in Western Canada. The salmon are raised inland in tanks with freshwater, leading to a ranking by SeaChoice and Seafood Watch as a consumer "best choice". (Overwaitea has committed with SeaChoice to a long-term plan to eventually offer only sustainable seafood in its stores, and this is a great step.)

The technology is still new, though, and farming salmon, no matter how it is done, comes with challenges. One of the biggest is that salmon is a carnivorous fish — it requires other marine resources as feed. In this case, the fish are given feed that includes ingredients made from plants and fish-processing byproducts, thus reducing the need to use other fish species. Recent research has also looked at using insects in fish feed.

Inland fish farms must also discharge used water, but water from these operations is treated to comply with environmental regulations. Recirculation systems are also being developed to reduce the amount of effluent from the fish farms.

The other issues include disease control and energy consumption. The most serious disease-related issues appear to have been addressed at the Domsea farm, in part by using clean water and constantly monitoring the fish, as well as ensuring that disease has no way of spreading to wild populations.

These systems can also use a lot of energy. But this is an easier problem to address than the many problems associated with open-net farms. Improvements in technology have helped make the closed farms more energy-efficient, and increased reliance on clean-energy sources will further reduce the environmental impact.

The industry still has a way to go before it can create a large supply of fresh salmon, but the fact that retailers are getting on board will help spur consumer demand and make the industry more viable. If this helps to resolve the problems associated with ocean-based salmon farming while taking the pressure off wild stocks and ensuring that people still have access to this great food, we'll all benefit.

Maybe the big question is, "How does it taste?" Robert Clark of Vancouver's C Restaurant, which offers inland farmed coho from B.C.'s Swift Aquaculture on its menu, says that, like Atlantic farmed salmon, it has a somewhat lighter, less fishy taste than wild salmon.

April 30, 2010
http://www.davidsuzuki.org/blogs/science-matters/2010/04/salmon-farming-may-be-a-good-idea-after-all/

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