A filmed underwater confrontation between an environmentalist who wants to shut down the aquarium fish industry in Hawaii and a collector who gathers the fish and sells them for a living has put a spotlight on a long-running conflict over the business.

The video shot off the west coast of Hawaii island May 8 shows a collector quickly swimming about 30 to 40 feet toward a diver, who is filming the collector, and ripping out the diver’s air-supply regulator. A snorkeler watching from above filmed the scene with another camera.

The state Department of Land and Natural Resources, which oversees state waters, said it is investigating "complaints by two parties involved in an incident" but declined to provide further details.

Rene Umberger, whose regulator was ripped out of her mouth, said she followed her training and calmly retrieved the regulator, gave it a gentle first breath to test whether it was functioning and resumed breathing. The regulator was torn, but it wasn’t taking in water and was working, she said.

"That’s your life-support equipment. Doing something like that to someone — you potentially cause them to die," said Umberger, who leads a Maui-based group called For the Fishes. "I was shocked."

The act could have killed a less experienced diver, said Umberger, who has been a dive instructor for 30 years and has been on more than 10,000 dives. She likened the act to attempted murder.

Umberger said an enforcement officer from the Department of Land and Natural Resources told her the aquarium fish collector had filed a complaint against her for harassment. She hasn’t been served with the complaint, Umberger added.

The state hasn’t charged the aquarium fish collector with any violation. The activists, who released the video this week, identified the collector as Jay Lovell.

His telephone number isn’t listed, and he couldn’t be reached for comment. But his brother Jim Lovell, who also collects aquarium fish, said the activists were harassing divers and provoked an incident.

"From what I understand, Jay was getting scared" of what was going on, Jim Lovell said. His brother was trying to do his job, he said.

Makani Christensen, an Oahu scuba spear fisherman who said he spoke to the brothers, said activists are trying to disrupt the work of fishermen.

"The fish go away. You can’t work under the stress when you have eight different divers around you," Christensen said.

Fishermen off the Kona Coast, where the incident occurred, account for 75 percent of the aquarium fish caught in Hawaii. Aquarium fish collecting is legal off Kona, but fisherman must avoid certain places and collect only certain species. The incident occurred in Keawa­iki Bay, where collecting is allowed.

Environmentalists say the aquarium fish trade strips coral reefs of fish that eat algae and otherwise support a healthy marine ecosystem.