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Salmon harvesting underway at a farm in Sekkingstad, Norway. (Photo: O. Hjellestad)
Norwegian salmon farms are the greenest
CANADA
Friday, November 06, 2009, 23:40 (GMT + 9)
Scientists have conducted the first worldwide life cycle assessment (LCA) of farmed salmon to gauge farms’ environmental impact.
Although less environmentally destructive than the beef industry and others, the aquaculture sector generates a hefty amount of pollution, reveals a study published in the journal Environmental Science and Technology on 23 October.
The LCA measures the collective energy use, animal resource use and greenhouse gas, acidifying and eutrophying emissions (such as phosphates) produced by salmon farms in Norway, the UK, Chile and British Columbia, Canada, the main salmon-farming countries.
As aquaculture has spread throughout the globe, production skyrocketed from a yearly 500 tonnes in 1970 to 1.5 million tonnes today. The environmental consequences are excessive energy use, contaminated coastal waters and depleted pelagic stocks, New Scientist reports.
Scientists studied the environmental impact of salmon farming throughout the supply chain in all four nations. Feed, mainly consisting of soy, fish and animal protein, was associated with the most environmental damage, according to Nathan Pelletier of Dalhousie University in Halifax, Nova Scotia and colleagues.
Farms in the UK consumed the most energy, emitted the largest amount of greenhouse gases and did worst on water acidification and material resource use (mainly fish for feed) of all the countries per tonne of salmon produced. Norway scored best.
"We found a 35 per cent difference in feed use per tonne of salmon produced between Norway and Chile, the least efficient region," Pelletier stated.
Norway has managed this chiefly because it uses a feeding system that produces very little waste. If all fish farming countries adopted Norwegian methods, the industry's greenhouse emissions would drop by 10 per cent, he said.
At the same time, Norway could halve its emissions if it resorted to more sustainable fish feed. Pelletier recommends that farms utilise plant-based salmon feed rather than animal-based (as long as soy-based feed does not involve deforestation to grow the legume).
Based on their results, the researchers will draft detailed recommendations on regulating the industry and help design eco-labels for consumers.
Related articles:
- Offshore salmon farms take heat from environmentalists
- Aquaculture's rapid growth poses new challenges
- Farmed salmon 'cleaner' than pork, beef: study
By Natalia Real
editorial@fis.com
www.fis.com
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