LOS ANGELES, United States (AFP) — US federal officials are seeking a ban on swimming with Hawaii’s spinner dolphins, saying the encounters popular with tourists are harming the nocturnal creatures’ sleeping habits.

The proposal by the National Marine Fisheries Service of the National Oceanic and Atmospheric Administration (NOAA) would ban swimming with Hawaiian spinner dolphins or approaching the animals within 50 yards (45 metres).

The measure would affect highly popular excursions that allow tourists to swim with the marine mammals or get near them by boat.

“We are taking this action because spinner dolphins in the main Hawaiian islands are experiencing intense pressure from swimmers and other ocean users looking for a dolphin encounter,” Ann Garrett, of the NOAA’s Fisheries Office of Protected Resources, told reporters earlier this week.

The playful and naturally curious creatures hunt for fish, shrimp and squid in deep waters offshore by night, and rest during the day in shallow waters.

They swim back and forth while resting with half of their brain alert while the other half rests.

Officials say the creatures have faced intense pressure in recent years from dolphin-viewing activities that disrupt their resting time.

Garrett said that her agency fears the chronic disturbance can negatively affect the mammals’ health and reproductive success.

“By reducing disturbance to Hawaiian spinner dolphins, we hope to prevent long-term negative effects to (them) and to protect the sustainability of the local population,” she said.

Garrett said her agency would consider public comment on the issue for 60 days and hold a number of community meetings in September before making a final decision within a year.

The proposed ban would be implemented within two nautical miles from shore of all main Hawaiian islands and in designated waters between the islands of Maui, Lanai, and Kahoolawe, where the dolphins are found throughout the day.

Although there is no firm count on the number of dolphins in the Hawaiian islands, the most recent estimate puts their number at 3,350, according to NOAA.

Victor Lozano, owner of Dolphin Excursions in Oahu, said the proposed regulations were welcome because many tour operators and individuals run amok in the waters as they seek out the dolphins with no regard for their well-being.

“I am all for the no-swim ban,” he said. “Some tour groups have no clue about the behaviour of dolphins and some people swim out toward them.”

However, he questioned how federal officials could enforce the ban on boats coming within 50 yards of the animals.

“What if I am sitting there and the dolphins come around me,” he said. “How do you manage that?”