BEVERLY - Today's pirates have dropped the skull and crossbones, but they're still out there sailing the high seas. Except instead of gold, they're after illegal fish.

Chilean sea bass, to be specific.

These tasty menu items live in the freezing waters off Antarctica and are on the brink of endangerment from overfishing. With such a high demand, especially in the United States, restaurants easily pay $18 a pound, and poachers go to extreme measures to ship them to America through the black market.

One of the leaders in the fight to stop them is Beverly resident Andy Cohen, who works for the National Marine Fisheries Service in Gloucester. He was honored recently for his role in putting these poachers behind bars.

How does he do it?

"The easiest way is when someone rats on someone else," Cohen said. "But the Southern Ocean is the biggest body of water on the planet, and it's very remote."

There exists in the international fishing industry a growing network of informants, intelligence officers and undercover agents - as Cohen was once - working to identify and infiltrate illegal fishing operations and bring these high-seas pirates to justice.

Posing as a criminal trying to purchase Chilean sea bass from unmarked vessels around the world, Cohen has arrested about a dozen poachers. Over the last 10 years, the National Marine Fisheries Service has convicted more than 50.

The felony carries a maximum sentence of five years in jail and a $250,000 fine - per incident. And there's usually more than one. The risk, however, is worth it.

"You can make as much money as a poacher as you can in the drug world - but it's harder to get caught," Cohen said. "If you see someone running down the street with a bag of heroin, a lightbulb goes off in your head. If you see a fish truck going down the street, you don't think twice about it."

He remembers one poacher who paid a $10 million fine.

"It makes me wonder what his net worth is," he said.

Now, Cohen has a desk job at the Fisheries Service office in Gloucester, and he was recognized for his help in developing an electronic tracking method that makes poached Chilean sea bass easier to identify when they're mixed in with legally harvested fish on their way to buyers. He also communicates with organizations around the world to share news and information.

"When you have such a specialized, worldwide syndicate like this, it's like a pyramid," Cohen said. "There's one guy on top, and he's a target of all our efforts."

Toothfish, anyone?

The Chilean sea bass is not a sea bass, and it's not from Chile. Its scientific name is the Patagonian toothfish, but 10 years ago when it was gaining popularity, some restaurant entrepreneur in California dubbed it the Chilean sea bass to make it sound more appetizing, Cohen said.

Yet it didn't need much help.

"In my opinion a bad Patagonian toothfish tastes better than a good codfish," he said. "And you can't ruin it. It can sit in a boiler for hours, and it still tastes good."

The meat is white, with a great texture and a mild flavor that goes with any sauce, said George Carey, who owns Finz on Pickering Wharf in Salem.

"It was originally recommended as a substitute for other fish that were being overfished, like cod, haddock and striped bass," he said. "The Chilean sea bass first started showing up in higher-end restaurants, mostly because there were chefs that were paying attention."

It became a trendy delicacy overnight. Finz used to serve the entree, but took it off the menu in 2001 when word began to spread about the fish's dwindling population.

"There are enough other choices out there that are local, fresh and sustainable," Carey said. He, along with many other restaurants around the country, pledged to "Take a Pass on Chilean Sea Bass" through the National Environmental Trust, a nonprofit that launched a public campaign to teach Americans about the hazards of eating "a long-lived, slow-growing fish that doesn't reproduce until it has evaded long-line fishing hooks for 10 years."

The United States is, by far, the largest market for Chilean sea bass, Cohen said. Nobody is quite sure why, but he has a theory.

"We're a rich country and willing to pay for a premium product," he said. "People in other parts of the world may not have the discretionary income to do that."

After working with 51 other countries around the world to stop illegal poaching, however, he believes it's finally under control, or at least getting there.

"At one point, we couldn't keep up with it. Now I'm confident most of the fish here is legal," he said.

The government has been successful not only in catching the criminals, but developing a case that's strong enough to convince a federal court to bring them to trial, and then have them convicted.

"You've got to sell it," Cohen said. "You've got to make it look sexy, and sometimes it's hard to make fish look sexy, but these guys do it."