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 grown "tremendously worse" in the past 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, 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 past three years. And four dead dolphins washed ashore with bullet wounds near San Diego, California, 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, Florida, 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.
"It's an area where the various fishery agencies need to come together and find a solution," said Wells, a researcher at Mote Marine Laboratory in Sarasota, Fla.
A federal agent who investigates reported attacks on dolphins said he hasn't noticed an increase in violence against them. But he said no one really knows the extent of the problem because so many confrontations likely occur 20 to 30 miles offshore in deep waters.
"That far out, the bodies are never going to wash up on shore," said Allan Coker, who works with NOAA's fisheries law enforcement office in Niceville, Fla.
Coker helped investigate a case last year when an informant reported that the captain of a 60-foot commercial fishing boat based in Panama City was making pipe bombs to toss at meddlesome bottlenose dolphin.
"When he was offshore and dolphins approached he'd light one and throw it in the water," said Coker. "The deckhands said it would rock the whole boat."
Authorities don't know if any dolphins were killed, but a judge sentenced Capt. Garry Alvin Key, 51, to two years' imprisonment in March after he pleaded guilty to illegally possessing explosives and taking or attempting to take marine mammals.
Two other captains, one from Florida and another from Alabama, have been placed on probation and fined $1,000 each since 2006 after admitting they shot at dolphins stealing fish from their boats. One used a .357-caliber Magnum, court records show.