HONOLULU — Federal regulators are proposing to ban swimming with dolphins in Hawaii, a move that could imperil one of the Aloha State’s most popular tourist activities and the industry that has sprung up around it.

The National Marine Fisheries Service says spinner dolphins — the playful nocturnal species that humans in Hawaii routinely frolic with — are being deprived of rest during the day and becoming stressed out.

Swimming with dolphins is popular with visitors and some locals, with dozens of companies on Kauai, Oahu, Maui and the Big Island operating dolphin tours daily.

The proposed rule could shut down or greatly disrupt the industry as it now operates. That’s because the ban would cover waters out to 2 nautical miles, which is where 98 percent of Hawaii’s spinner dolphins rest after they’ve spent the night feeding. Tour companies take customers to these close-to-shore waters to find dolphins.

There has to be a middle ground between the dolphin tour operators and what federal regulators are proposing, said Richard Holland, CEO of Dolphins and You, which takes about 80 customers on tours to waters off Oahu’s Waianae Coast each day. Customer reviews of his business on social media and other online sites often mention how their lives have been changed by going on a tour, he said.

“If you’re doing work that helps people — that enlightens them, inspires them, makes them feel good — that’s a good thing. There’s no need to take that away,” Holland said.

Ann Garrett, assistant regional administrator of the National Marine Fisheries Service’s protected resources division for the Pacific Islands, said dolphins have been found to be burning calories at a higher rate because they are forced to be vigilant as people approach their pods.