The underwater scuffle between the two divers is apparently the product of a long-running conflict over the aquarium fish industry.

Environmentalists want to shut down the industry in Hawaii, but collectors who gather aquarium fish gather and sell them for a living.

A video released this week shows one diver ripping the air regulator out of the mouth of an activist who was filming him. The diver says she was able to get the regulator back in her mouth and kept breathing, but says that could have killed a less experienced diver.

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