Just when we've fallen in love with Chilean sea bass, a group of chefs has risen to warn us we could love it to death.

Only a few years ago, this was a fish living in obscurity in deep, cold ocean waters off South America and with the unappetizing name of Patagonian (or Antarctic) toothfish. But like an aspiring Hollywood starlet, its name was changed and it became a hit. No one cared that Chilean sea bass wasn't really a bass and didn't always come from Chile. With its white, moist flesh, it took leading roles in top American restaurants.

Now, the popularity of this fish threatens to become its downfall. For the last two years, the United States and other countries concerned about overfishing and exploitation of this species have regulated the harvest of Chilean sea bass and confiscated illegal catches -- when they could.

But environmental advocates warn that the regulation isn't enough, that the documentation

that U.S. agencies require can be forged easily, and that unless diners "take a pass on Chilean sea bass," as the campaign slogan goes, the species will die off.

Some 500 American chefs have pledged not to serve or sell the fish until its population stabilizes. Their campaign is coordinated by the nonprofit National Environmental Trust and supported by other environmental groups.

One of those chefs is Nora Pouillon, owner of two popular Washington, D.C., restaurants -- Nora and Asia Nora. She was the spokeswoman behind a campaign two years ago to boycott North Atlantic swordfish for the same reasons she's now concerned about Chilean sea bass.

"You want them to be able to reproduce a couple of years before you catch them," Pouillon says of the fish.

She stopped serving swordfish when the steaks became smaller and smaller. It didn't take much to put two and two together, she said, and figure out the swordfish weren't getting a chance to live to adulthood.

While some chefs questioned whether such boycotts of fish make a difference, Pouillon is convinced they do.

"Seventy percent of the sales [of Chilean sea bass] in the United States are to restaurants," Pouillon says.

While the regulation of swordfish harvesting has improved because of the boycott, she says, she still does not serve the fish, and would like to see more regulation of the size of fish caught.

Whether Chilean sea bass or swordfish, she says, "I think you can live without it."

Chilean sea bass is not classified as endangered, but large, unreported catches from illegal fishing make it difficult to manage the population, according to a fact sheet put out by the U.S. departments of Commerce and State. Legal fishing goes on in defined management areas, but the amount of fish caught illegally may be twice that caught legally.

And then, there's the concern about catching fish that are too small and too young, says Andrea Kavanagh, a spokeswoman for the National Environmental Trust, based in Washington.

The toothfish/Chilean sea bass needs to be about 8 years old before it can reproduce, Kavanagh says, but some illegally caught fish are younger and smaller than that.

"People ask, 'Can you farm-raise it like other sea bass?'" Kavanagh says. "No, because first of all, it's not a sea bass, and second, it lives in very cold, deep water."

Now, there are some chefs, restaurant diners and home cooks who need to hear no more than that to take a pass on Chilean sea bass.

Why risk overfishing this species, they might say, when there are plenty of other fish in the ocean?

Well, for one thing, there aren't plenty of fish with such rich flesh. Pouillon and others recommend halibut, but you have to be careful not to overcook it. Chilean sea bass is not as vulnerable to that common mistake.

"We have a tendency to overcook the majority of seafood," says Dana Spatafore, general manager of Graul's Markets. Chilean sea bass has a high oil content that keeps it from succumbing to the dryness that plagues most overcooked fish. That, and the mild, sweet flavor, keeps the fish popular in his stores despite the price of $16.99 per pound, he says.

At Tapas Teatro in Baltimore, the Chilean sea bass goes into the paella, or is grilled and served with spinach. Chef Antonio Baines says the restaurant buys its seafood from a reputable supplier who takes "every precaution" to follow the law. He has no plans to stop serving Chilean sea bass.

And Michael Marx, owner of Blue Agave in Federal Hill, plans to continue to serve his signature dish of plantain-encrusted Chilean sea bass served with mango-habanero sauce.

Sea bass not only doesn't taste "fishy," its texture is almost meaty, he says. Marx says he has occasionally had shipments that he felt were subpar, when fisheries were "grabbing anything that was out there" to meet the demand. He sent those shipments back, he says. And he has had to face price increases of $3 per pound, without changing the price on the menu.

But he says he's not convinced the species is in danger or that chefs can make much difference if it is.

"What would it take for me to take it off the menu? The only reason would be if the quality changed," he says.

Cooking tip

Both Chilean sea bass and halibut lend themselves well to a simple preparation.

Either fish can be seared in an oil-coated, oven-proof frying pan 2 to 3 minutes on each side, then baked in a 400-degree oven. Chilean sea bass should be baked for 10 to 12 minutes. Halibut should be checked after 4 minutes.

Halibut With Peppers, Red Bliss & Fingerling Potatoes

Serves 4

4 teaspoons olive oil, divided use

1 medium onion, thinly sliced

2 teaspoons minced garlic

2 green peppers, seeded and julienne

1 red pepper, seeded and julienne

1 yellow pepper, seeded and julienne

1 cup white wine

2 to 3 tablespoons assorted herbs such as thyme, oregano and rosemary

sea salt and freshly ground black pepper

1 1/2 pounds halibut fillets, cut into 4 portions, seasoned with salt and pepper

small bouquet of assorted herbs such as thyme, oregano and rosemary, for garnish

Preheat the oven to 450 degrees.

Heat 2 teaspoons of the olive oil in a medium saute pan. Add the onion, garlic and peppers and saute for about 3 minutes, stirring frequently. Add the wine and herbs and season to taste with salt and pepper and bring the mixture to a boil. Spoon the pepper mixture into a baking dish large enough to accommodate the four fish fillets in 1 layer.

Clean the saute pan and heat until nearly smoking. Add the remaining 2 teaspoons of olive oil and immediately sear the seasoned halibut fillets for 1 to 2 minutes. Remove with spatula and place on top of pepper mixture, seared side up. Bake 7 to 10 minutes or until desired doneness.

Serve with steamed or boiled new potatoes and a dollop of aioli (optional), and garnish with bouquet of fresh herbs.

-- Nora Pouillon

Mango-Habanero Sauce

4 mangos, soft and ripe

2 shallots, minced

1/2 habanero pepper, minced

2 tablespoons vegetable oil

1 1/2 cups vegetable stock (or water)

juice from 3 limes

kosher salt to taste

Peel, slice and chop mangos in large dice. In a saucepan over medium heat, saute shallots and habanero until translucent. Add mango and stock. Cook over medium heat for about 10 minutes or until mango is soft. Add to food processor or blender and puree. Add lime juice and salt to taste. Strain through medium-hole strainer.

Plantain-Encrusted Sea Bass

Serves 6

3 green plantains

2 cups vegetable oil

1/2 pound Chilean sea bass, cut into 6 four-ounce portions (may substitute halibut)

1 cup flour

4 large eggs

Mango-Habanero Sauce (recipe below left)

Salsa de Frijoles (recipe follows)

Peel plantains and slice thinly. In a large saucepot, heat oil (reserve 3 tablespoons to saute) over medium-high heat. Place plantain slices in hot oil a few at a time. Fry until lightly browned. Drain and cool on paper towel.

Preheat oven to 400 degrees. Place plantain chips in food processor and chop to medium-fine. Lightly coat fish portions in flour.

Beat eggs with fork or whisk until well mixed. Dip each piece of fish in egg mixture thoroughly. Then, roll in plantain crumbs until well-coated. In an oven-proof saute pan, over medium-high heat, sear both sides of fish (lightly brown). Add 1/2 cup of water to pan and finish in oven at 400 degrees for approximately 8 to 10 minutes, depending on thickness.

To assemble, drizzle Mango-Habanero Sauce on plate, place fish on sauce and top fish with Salsa de Frijoles.

- Michael Marx

Salsa de Frijoles

1 cup cooked black beans

1/2 cup jicama, diced

2 tablespoons cilantro, chopped

2 serrano peppers, minced

1 teaspoon sherry vinegar

1 tablespoon olive oil

kosher salt to taste

Mix well in bowl and garnish fish with salsa.