A vegetarian fishery

The novelist Paul Greenberg had a terrific op-ed about sustainable fisheries in last week's NY Times. Take a look, if you haven't already. The key premise behind the popular sustainable seafood guides - that we should eat and farm 'vegetarian' fish - is rarely articulated this well:

"... go vegetarian, in a manner of speaking. Farmed fish have gotten a bad name in recent years — even while our production of them has grown to rival the wild fish harvest, as the Food and Agriculture Organization reported this week. This is mostly because the farmed fish we eat in the West are carnivores. Raising carnivores like salmon requires the capture of wild prey fish that wild fish also consume. By eating farmed carnivores we rob Peter to pay Paul, stealing the food source for wild fish and feeding them to farmed."

That's why farmed tilapia and carp are deemed OK by the Monterey Bay Aquarium seafood guide (and others) but farmed salmon is not. Farming salmon is like using (carnivorous) wolves rather than (vegetarian) cattle as livestock.

Greenberg applies a similar argument to some threatened pelagic (open-ocean) fisheries:

"... don’t eat the big fish. Dining on a 500-pound bluefin tuna is the seafood equivalent of driving a Hummer. Ten pounds of little fish are required to produce one pound of bluefin and all the pollutants contained in a tuna’s prey “bio-concentrate” in a tuna’s flesh, making it a particularly compromised animal, chemically speaking. And because it takes so many little fish to make a big fish, the sea can sustain only a relatively small amount of large fish."