Bottlenose dolphin swim alongside a fishing boat June 18 in the Gulf of Mexico miles off the coast of Panama City, Fla. Boat captains say the marine mammals are getting increasingly aggressive in their quest for food, with some taking fish off hooks, a pesky stunt that rarely happened just a few years ago.

Panama City, Fla. ? Miles offshore, a fight is raging between angry anglers armed with guns and bombs and bottlenose dolphins, the marine mammals popularized in movies and TV shows like “Flipper.”

Boat captains say dolphins, known for their toothy grins and playfulness, are growing increasingly aggressive in their quest for food, with some taking fish right off the hook — something that rarely happened just a few years ago.

In response, fishermen are pulling out everything from pipe bombs to .357-caliber Magnum pistols to fend them off — and breaking a federal law against harming the sea mammals.

The head of a national fishing organization, Bob Zales II, said the problem of bottlenose dolphins stealing fish has gotten “tremendously worse” in the last year. So have stories of retaliation by angry boat captains and ordinary anglers, who are paying hundreds of dollars for even short fishing trips because of high fuel prices.

“You have people who are getting so frustrated they’re shooting at them,” said Zales, of Panama City, who has fished for more than four decades and is president of the National Association of Charter Boat Operators.

The captain of a Florida-based fishing boat is serving two years in prison after pleading guilty earlier this year to making pipe bombs and tossing them at dolphins, which are protected by federal law.

Two other captains have pleaded guilty to shooting at the animals in the Gulf of Mexico, home to tens of thousands of dolphins, in the last three years. And four dead dolphins washed ashore with bullet wounds near San Diego, Calif., in 2007. Authorities offered a reward in the shootings, but no one was charged.

It’s dangerous for dolphins to compete with people for fish, regardless of whether anglers fight back. Forty-six of the animals are known to have died along the Florida coast since 2005 after either swallowing recreational fishing gear or becoming entangled in lines, according to NOAA’s National Marine Fisheries Service.

Marine experts and boat captains agree there’s a problem, but they differ over why some animals have become so brazen.

Stacey Hortsman, dolphin conservation coordinator with the National Marine Fisheries Service in St. Petersburg, Fla., said studies have linked the dolphins’ behavior with people feeding dolphins, often from sightseeing tours that are common in many resort areas. Dolphins learn to hang around people for food handouts, she said.

“It’s a very complex management issue for us because it is such a widespread problem,” said Hortsman.

Zales blames the problem on state and federal fishing limits enacted in recent years to protect against overfishing of species like red snapper.

Rather than saving fish, he said, the rules cause many anglers to throw back large numbers of undersized ones — oftentimes right into the jaws of waiting dolphins.

“With us having to throw fish back, (dolphin) literally now live in different places where we go fish,” Zales said. “They know they have a free meal.”

Dolphin expert Randall Wells said anglers shouldn’t release fish around dolphins. But regulations require anglers to throw back undersize and excess fish without accounting for the presence of the mammals.