The federal government is proposing a ban on swimming with dolphins in Hawaii – a move that may crush the dreams of many tourists, but will allow the marine mammals to finally get a good day’s sleep.

The proposed rule would bar people from swimming or approaching within 50 yards of the Hawaiian spinner dolphin. The dolphins are an increasingly popular attraction for tourists, who pay for chartered tours of the bays the dolphins frequent.

Spinner dolphins are nocturnal, foraging in the deep ocean at night and returning to shallow waters to rest during the day, said Susan Pultz, the chief of conservation planning and rule-making for the National Marine Fisheries Service.

“When you get the numbers [of tourists] we’re seeing, they’re constantly disturbed all day long. That’s their resting period,” said Pultz.

“As we all know, if you don’t rest day after day after day, it does affect your fitness.”

Spinner dolphins continue swimming while they are sleeping, so people may not be aware they are waking the cetaceans up.

The predictable habits of spinner dolphins have been taken advantage of by commercial tour operators, who know exactly where and when to find the resting creatures.

“At some locations, up to 13 tour boats have been observed jockeying for position on a single dolphin group, with up to 60 snorkelers in the water,” the rule reads. “In addition, organized retreats centered on dolphin encounters, dolphin-assisted therapy, and dolphin-associated spiritual practices have flourished in certain areas.”

Pultz said her agency has observed changes in dolphin behavior due to the increase in human interaction, including dolphins avoiding people, increasing their aerial behavior, and leaving bays when too many boats were present, all of which require them to expend extra energy.

“We see all the time boats going right through the pods, separating the moms and the calves,” she said. “It’s just not a good situation at all.”

Victor Lozano, the owner of Dolphin Excursions in Oahu, said he welcomed the new regulations.

“It’s long overdue. We’re ready for it,” Lozano said, emphasizing that he wanted to see the regulations enforced against boats and swimmers alike.

Lozano has been providing boat tours for 23 years and said that the behavior of people toward the dolphins had gotten out of control, which he blamed on the desire for “self-gratifying selfies”.

“People chase the dolphins with the selfie sticks,” he said. “You go on safari – you don’t go out to the lion and try to pet it.”

Harassing spinner dolphins – or any marine mammal – is already illegal under the Marine Mammal Protection Act. The proposed rules would clarify that getting within 50 yards of a spinner dolphin is considered illegal harassment.

The government has previously passed specific regulations barring people from approaching within 100 yards of humpback whales in Hawaii and Alaska and killer whales in the Puget Sound. This would be the first rule addressing swimming with spinner dolphins.

The proposed rule now enters a 60-day public comment period, and Pultz said it would probably not be finalized for a year.

Katie Paki, who works on a boat offering dolphin and whale-watching tours on Maui, said her company did not allow its customers to swim with dolphins anyway.

“They get to see them and take pictures form the boat,” she said. “It’s a dolphin experience. You’re just not swimming with them.”