Guest Post by Dan Shapley of The Daily Green
When it comes to buying fish, the choices have rarely been easy for a shopper trying to make a sustainable choice. There are different stocks of fish (some healthy, some depleted, some clean and some polluted) caught in different ways (some sustainable, some destructive) and then there are farmed fish (some farmed sustainably, some highly polluting, or even polluted). It's confusing enough that there are several guides to buying sustainable seafood published to make the decision-making easier.
But for salmon, one of America's most popular fishes, the choice has been relatively straightforward: wild Alaskan salmon may be more expensive, but it's more sustainable. It's caught from a healthy wild stock with sustainable methods, is free of contaminants, and avoids the problems with farmed salmon, which can not only pollute local waters near the farm but also be polluted themselves because of the fish meal they're fed.
That's true ... but. There's always a "but." Of course it's just not that simple -- not according to a new report by Ecotrust, an environmental think tank of sorts based in Portland, Ore., which worked with the Swedish Institute for Food and Biotechnology and Canada's Dalhousie University on what they call the "world's first comprehensive global-scale look at a major food commodity from a full life cycle perspective."
In other words, the researchers wanted to get to the bottom line when it comes to the environmental impact of a single food. They chose salmon -- a food that they acknowledged has a low impact relative to other foods, but which is nonetheless a popular food with a measurable impact on the global environment, when you take into account climate change, ozone depletion, loss of critical habitat and ocean acidification. (Importantly, the researchers were concerned primarily with global-scale environmental problems, and not local pollution, local stocks of fish nor the human health impacts of nutrients or contaminants in fish.)
The result: The traditional fish market questions -- farmed of wild, organic or conventional -- don't matter as much as we all thought. What does, or does not matter:
Frozen or Fresh
"Air-freighting salmon, and any food, results in substantial increases in environmental impacts. If more frozen food were consumed, more container ships would be used to ship food. Container ships are by far the most efficient and carbon-friendly way to transport food. Globally, the majority of salmon fillets are currently consumed fresh and never frozen. In fish-loving Japan, which gets much of its fish by air, switching to 75 percent frozen salmon would have more benefit than all of Europe eating locally farmed salmon."
Wild or Farmed
"Contrary to what is widely perceived, the vast majority of broad-scale resource use and environmental impacts (energy inputs, GHG emissions, etc) from conventional salmon farming result from the feeds used to produce them. What happens at or around a farm site may be important for local ecological reasons but contributes very little to global scale concerns such as global warming.... Reducing the amount of animal-derived inputs to feeds (e.g. fish meals and oils along with livestock derived meals) in favor of plant-based feed inputs can markedly reduce environmental impacts.
"In general, salmon fisheries result in relatively low global-scale environmental impacts. However, substantial differences exist between how salmon are caught. Catching salmon in large nets as they school together has one tenth the impact of catching them in small numbers using baited hooks and lures."
Organic or Conventional
"Growing organic salmon using fish meals and oils from very resource intensive fisheries results in impacts very similar to conventional farmed salmon production."
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