The Straight Dope - What's better, farm-raised salmon or wild?

Are upscale restaurants serving ugly fish?

On the one hand, I want to eat farm-raised salmon because wild salmon is being depleted by overfishing. On the other hand, I hear there are all sorts of pollutants in salmon farms, and farm-raised fish are full of antibiotics. So which is better, farm-raised or wild?
— Judith
I've heard most fish served in fast-food eateries is an ugly whiplike critter from the waters off New Zealand. I don't eat at such places but wonder how far up the restaurant scale these things travel. How many fish once considered garbage are now served with a more palatable name?
— Chris Schneider, La Jolla, Calif.
Chris, meet Judith — fellow sufferers in a world running out of fish. The difference is Judith seems to recognize our plight and you don't. Since your need is more urgent, we'll eradicate your ignorance first.
Let's begin with your idea that the discriminating diner eats only attractive fish. This is an unusual culinary concept. One concedes that the hoki, the New Zealand fish you refer to, is probably not something you'd want to see in a tank at the dentist's office. (It's long and skinny with undersized fins and is reminiscent of an eel.) However, having had one plopped on my plate, I'm not going to tell the waiter: This critter is far too homely to satisfy my appetite — please spear me something cuter. The hoki has firm flesh high in omega-3 acids and makes a fine fish sandwich at McDonald's. Equally important, unlike more comely fish, there are (for now) a fair number of them left.
That's the basic problem, you see. Remember the cod, seemingly infinite in number and fished for centuries in the North Atlantic? The fishery collapsed in 1992, the victim of rapacious factory fishing and shortsighted management. The number of cod today is something like 1 percent of what it was in the 1960s. Forty thousand people were thrown out of work. It's not known when, if ever, the fishery will recover.
Similarly, the West Coast salmon fishery failed in 2008. The Atlantic bluefin tuna has been reduced to about 15 percent of preindustrial numbers, and fishing has been scaled back; some think even the lower catch will destroy what remains. In a 2006 paper, researchers led by Boris Worm of Canada's Dalhousie University reported that 30 percent of world fisheries had collapsed, with catches falling below 10 percent of the original yield. They projected the remaining commercial fish species would be exhausted by midcentury, meaning no more wild fish, pretty or not.
Given dwindling supplies, it's not surprising that you're running into a bit of bait and switch. The FDA recently determined that 37 percent of fish and 13 percent of other seafood was mislabeled. As much as 77 percent of so-called red snapper is anything but. The FDA has established guidelines for fish labeling, but thanks to industry lobbying there are plenty of exemptions. This has led to some surreal mislabeling: Importers started selling Vietnamese catfish under the brand name Cajun Delight. Other species have been given more appealing monikers as well. The rock crab, once a garbage catch, was reborn as the peekytoe crab. The channel catfish has become the Southern trout, dolphinfish is now mahi mahi, and the Patagonian toothfish is now the Chilean sea bass. The Malabar blood snapper was renamed scarlet snapper. The fish known as orange roughy used to be called the slimehead.
So, are less desirable fish finding their way into fancy restaurants? Yes, because increasingly that's all there is left.
As for you, Judith, I've got some bad news and some worse news. The bad news is that, as you've heard, farmed salmon is problematic. Studies from around the world have found that farm-raised salmon contain more cancer-causing PCBs and dioxins than wild ones do, typically originating in their feed. In some cases, the levels of contaminants are so high that by EPA guidelines you shouldn't even have one serving a month — it’s more like one every five months in the case of some northern European farmed salmon. Researchers estimate that the risk of cancer from contaminants is about three times higher for farmed salmon compared to wild.
Salmon farming is rough on the environment, too. Farm runoff has been linked to increased mercury levels in wild fish nearby. Fish parasites can run rampant in salmon farms and spread into the wild. Fish feces, copper, and zinc can contaminate the waters surrounding salmon pens.
Even the good stuff in farmed salmon comes with problems. Yes, farmed salmon contain more oil overall than wild, including heart-friendly omega-3, but a much greater percentage of the oil is in the form of not-so-healthy omega-6.
The worse news is you'd better get used to it. Commercial salmon fishing is gone in the Atlantic, and things don't look promising in the Pacific. In a perfect world, wild salmon would be a better choice than farmed. But we had a perfect world as far as fishing was concerned, and we used it up.
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