“He has no intention of harming or disturbing in any way these mammals who grace the ocean,” DeLima said.

The ruling, issued May 31, found Cho violated the Marine Mammal Protection Act by “leapfrogging.” That’s when tour boats repeatedly offload swimmers in the path of dolphins as the animals swim along the coast. The ruling found dolphins were swimming below the surface at the beginning but came to the surface in the presence of the tour boat and people.

The judge, Christine Donelian Coughlin, also found Cho circled the dolphins with his boat, generating a significant wake. The dolphins began leaping and spinning in the air after this activity, which Cho described as doing “donuts,” the ruling said.

Hawaii’s spinner dolphins get their name from their aerial acrobatics. The behavior is sometimes playful, but it can also be an attempt to alert other dolphins to danger. The ruling found the dolphins in this case were leaping in response to harassment from Cho’s boat.

Garrett, who is the assistant regional administrator of the National Marine Fisheries Service’s protected resources division for the Pacific Islands, said her agency has issued verbal and written warnings to tour operators over the years.

But this is the first fine.

“We’re hoping that it will send a message that there are activities that are disturbing the dolphins,” she said. “Some of the tour operators — we would like to see them behave in a different way.”

Garrett’s office last year proposed requiring swimmers to stay at least 50 yards from spinner dolphins in Hawaii out of concern tours are stressing the animals and depriving them of the rest they need. The rule would likely have a major effect on dolphin tours, which have become a popular way for tourists to view Hawaii wildlife.

NOAA is currently reviewing feedback it received on the proposal. It’s also working on an economic analysis conducted to determine how the proposed rule would affect businesses. It expects to finalize a rule within the next 12 months, Garrett said.

Cho is manager and owner of Auwana Hawaii, LLC which does business as Adventure X Boat Tours on the Kona side of the Big Island.