It’s not easy being green.

I flashed on Kermit the Frog this weekend as I tucked into a flaky, tender, deep-fried red snapper at Rudy’s Taste, a Guatemalan/Mexican/Caribbean joint on Ashland. (And if you’ll allow a brief, fishy digression, the presentation here is something awesome: a ten-inch whole fish–gills, teeth, eyes, and all–the skin scored into a little checkerboard pattern and fried to a reddish-gold crisp, nestled between piles of rice and grilled veggies. Not for the first time did I kick myself for not having a camera phone. If I don’t get one soon they’re going to take away my membership in the food nerds’ club.)

Anyway. The snapper was delicious. Until about halfway through something floated up from the memory banks: “Oh, crap. It’s endangered.”

Until Al Gore makes a movie about it, the global overfishing crisis seems doomed to remain the pet cause of impassioned small-interest groups. It’s hard to relate to fish. They aren’t very personable: they’re mute and cold-blooded and finned. Their habitat is largely invisible to humans. They’re a good low-fat, tasty source of protein–not to mention those trendy Omega-3 fatty acids. And unlike penguins, or polar bears, they don’t have much of a cute factor working on their behalf. But the subject’s come up for me twice in the last week, in two interviews I did with two very different chefs, both of whom used almost identical language to make their point: If we don’t do something now, the ocean’s supply of seafood will be gone in 40 years.

The estimate of 40 years comes from an article published in the November 3, 2006, issue of Science. (If you’re not a member of the American Association for the Advancement of Sciences or don’t want to pay $10 to access the whole thing, here’s a good summary from the Washington Post.) Unsurprisingly, the fishing industry disputes the findings, arguing that adequate steps have already been taken to end deep-sea trawling and dredging and stimulate aquaculture. As Lucy Seigle, of the Guardian, discovered, it’s all overwhelmingly complicated–if the world’s seafood stock is in crisis, where are all those glistening tuna steaks coming from?

The day after the snapper incident, guilt rising in my gorge, I dug out a copy of Charles Clover’s The End of the Line: How Overfishing is Changing the World and What We Eat. It was published here last year after coming out in England in 2004, and despite the fact that the title relies on the apparently inevitable pun common to most articles about this stuff (cf. the Guardian, the Post), it’s an exhaustive and exhortatory piece of investigative journalism. Here’s how Clover describes trawling:

“Imagine what people would say if a band of hunters strung a mile of net between two immense all-terrain vehicles and dragged it at speed across the plains of Africa,” he begins, conjuring a horrific image of rhinos and wildebeests caught in its snare. “Picture how the net is constructed, with a huge metal roller attached to the leading edge. This rolling beam smashes and flattens obstructions, flushing creatures into the opposing filaments. The effect of dragging a huge iron bar across the savannah is to break off every outcrop and uproot every tree, bush, and flowering plant, stirring columns of birds in the air. Left behind is a strangely bedraggled landscape resembling a harrowed field.”

It’s not exactly a fun read, but if you’re into this stuff it’s invaluable. At the back there’s an appendix that functions as a consumer guide, breaking down seafood into “fish to avoid” such as Atlantic cod, Chilean sea bass, and, yes, red snapper; “fish to be wary about” (shrimp, some tuna); and “fish to eat with a clear conscience,” including herring, mackerel, tilapia, and, thankfully, Pacific salmon. A similar guide (PDF) is available in a handy pocket-size format on the Shedd’s Web site, part of the aquarium’s Right Bite program–itself modeled on the Environmental Defense Network’s Oceans Alive campaign. The Shedd’s guide also flags certain species with a cheery note about mercury and other contaminants.

Now go on–enjoy your sushi.