The common name "grouper" is slapped on more than two dozen species of fish now swimming around the Atlantic Ocean, including mutton hamlets, speckled hinds, coneys, Jewfish and scamps. But when Charleston eaters encounter grouper on menus and in seafood cases, they're usually dealing with red, black or gag grouper. Whether those species count as sustainable depends on who's doing the assessing.

According to Seafood Watch, the buying guide administered by the Monterey Bay Aquarium, "red grouper is a critical conservation concern" and "the gag grouper stock status would normally be classified as poor." Atlantic black group stocks are more robust, but since all three fisheries are generally lumped together for management purposes, Seafood Watch suggests eating mahi mahi or striped bass instead.

But Shelley Dearheart, coordinator for the Sustainable Seafood Initiative at the South Carolina Aquarium, says her organization has reached a different conclusion.

"Red and black grouper are probably the two (groupers) we'd recommend most readily," Dearheart says. "Neither are considered overfished stocks and overfishing is not occurring either. They are all caught with hook and line gear, so bycatch and habitat destruction are minimal, as well."

Here are seven more things to know about grouper before reaching for a lemon wedge:

1. Grouper's popularity is partly attributable to its mild flavor; it's often described as "a fish for people who don't like fish." Both red and black groupers have lean, white flesh, but red grouper is leaner, sweeter and not quite as firm as black grouper. Taste-wise, gag grouper and black grouper are very similar, so gag grouper is sometimes marketed under the black grouper name.

2. The average grouper weighs about 15-20 pounds, but the annals of recreational fishing are rich with tales of much bigger groupers that didn't get away. Because groupers can live as long as 40 years, there are many instances of them growing to more than 500 pounds. Last summer, a Mount Pleasant fisherman reeled in a 48.5-pound gag grouper, tying the South Carolina state record.

3. In the Arab world, groupers are known as hamours. The same name is applied to greedy businessmen who devour their rivals in much the way that fast-growing groupers munch on shrimp, crab and other sea creatures

4. Groupers are protogynous hermaphrodites, which means they start out as females then switch to malehood after maturity. Male groupers surround themselves with harems of a dozen females; if a harem is lacking a male fish, one of the females will change her sex.

5. Although grouper is pretty on the plate, the fish is slow and stout, with a large mouth turned down into what looks like a perpetual frown.

6. Grouper is suitable for an array of cooking methods: It can be fried, blackened, broiled, baked, grilled, poached, steamed or baked. And since grouper's so mild, it easily absorbs flavors.

7. Like most fish, grouper is high in protein and low in fat, making it a healthy choice. But the environmental advocacy group Natural Resources Defense Council lists it as a high mercury fish, along with bluefish and canned tuna, so eaters at risk for mercury exposure should consider monitoring their consumption.