For many, the experience is a commune with ancient powerful forces, pure ecstasy in the form of oneness with nature. For others, it is a rare educational experience.

But for the National Marine Fisheries Service, latching onto a dolphin's back to ride a wave is "harassment," and it wants the thousands of people swarming to Florida and Hawaii each year to swim with the dolphins to knock it off.

"These animals aren't water toys or pets — they need to be afforded the same respect as their terrestrial counterparts," said Trevor Spradlin, a marine mammal biologist for the National Marine Fisheries Service, which has proposed a new regulation that would label swimming with wild dolphins, as well as whales, porpoises, sea lions, or seals, a form of harassment.

"These animals are trying to rest, avoid predators, digest their food, but they're being harassed by people who are trying to get up close and personal with them," Spradlin said.

The National Marine Fisheries Service, a bureau of the Commerce Department, is finding some unlikely allies. Fred Jacobs, a spokesman for Sea World, said his organization backs the proposed regulations, which would clarify the existing Marine Mammal Protection Act to make interaction with marine animals a violation punishable with fines up to $20,000 and jailtime as much as one year.

"Whether it is a dolphin, a whale or any animal in the wild, we discourage anyone from interacting with them," Jacobs said. "Anyone who comes to our facilities will not walk away with any other message."

But some animal advocates say it is tourist attractions like Sea World and the large number of organizations that sponsor swims with dolphins that worsen the problem.

"I blame the media. I blame Sea World," said Naomi Rose, a marine mammal scientist with the Humane Society of the United States.

Rose said images of "Flipper" and the amazing stunts animals are forced to do at theme parks — along with the "new age types" and other business operators who "chronically" interact with dolphins — have led people to believe that their interaction is benign, when in fact it is extremely disruptive.

"My concern with a lot of people is that they interpret 'harassment' through their own lenses. They assume that because they want to be with the dolphins so badly that the dolphins want to be with them. That's a mistake."

Dolphin riders say they take great care not to injure or bother the dolphins, and even if the federal government crafts a law, it may have trouble stopping dolphins from wanting to swim with their human playmates.

"Who is going to tell the dolphins they can't swim with us anymore?" asked Joan Ocean, who has written several books about dolphin communication and has led seminars on dolphin telepathic communication and interactivity with people.

Ocean, who is based in Hawaii, where she swims each day with the dolphins in the lagoon outside her back door, admits that some people pursue dolphin pods and engage in rough play. But, she said, that can be stopped through education.

"Our mission is to educate people, tourists particularly, about a natural, enriching experience of interacting with dolphins in the wild," echoed Michel Atlas, founder of the Human Dolphin Institute in Panama City, Fla., which runs dolphin interaction seminars for adults and children.

Atlas said his organization, which serves about 1,000 tourists each five-month swimming season, completely agrees with the federal government's desire to outlaw the harassment of dolphins, but he doesn't think the activities he sponsors should be placed in that category.

"The dolphins come to say hello to people whether they are being fed or not," he said. "They come to us, and if they do, we put people in the water."

The public comment period for the proposed regulation ended April 1, Spradlin said. The agency will consider the more than 500 letters of feedback before deciding whether to issue a final rule, which could be written as early as this summer.