Federal authorities are investigating a group of swimmers who are alleged to have been caught on camera harassing a pod of dolphins Sunday in violation of federal law, officials announced this week.
A video drone deployed by officers with the state Department of Land and Natural Resources recorded the 33 swimmers "aggressively pursuing, corralling, and harassing the pod" in Hōnaunau Bay on Sunday morning, officials alleged Tuesday.
The 39-second clip, which the agency posted online, appears to show over a dozen of the swimmers pursuing 11 dolphins. The dolphins eventually split off into two directions, and some of the swimmers turn around and appear to stop pursuing some of them.
The allegations could violations of the Marine Mammal Protection Act, a law enacted in 1972 that makes it illegal to harass wild marine mammals, including dolphins, whales, seals and sea lions.
The act stipulates two levels of harassment, according to the National Oceanic and Atmospheric Administration: one referring to "any act of pursuit, torment, or annoyance" that could injure a marine mammal and another referring to "acts that have the potential to disturb (but not injure) a marine mammal" by disrupting their breeding, feeding and other routines.
The spinner dolphins involved in the incident are also protected by a specific rule published in 2021. It prohibits swimmers and vessels from coming within 150 feet of the dolphins within 2 miles of the Hawaii shoreline, said Katie Wagner, a NOAA spokesperson.
Spinner dolphins — smaller members of the species known for leaping and spinning out of the water — may be sleeping even when they appear to be awake and moving through the water, The Associated Press reported. That's because half of their brains remain "awake" while they swim, helping them breathe and remain on the surface of the water.
NOAA warns that disturbing spinner dolphins could disrupt their daytime rest, negatively affecting their health and reproduction and leading them to become aggressive or avoidant.
Officers with the Hawaii agency's Division of Conservation and Resources Enforcement, who were conducting what officials described as a "routine patrol" in the area, deployed the drone after they spotted the swimmers from land Sunday, DLNR Senior Communications Manager Dan Dennison said.
The officers alerted the swimmers to the alleged violation while they were still in the water and then met them on land, where they initiated a joint investigation with the NOAA Office of Law Enforcement, the news release said.
The swimmers have not been publicly identified.
It was not immediately clear what kind of penalties they could face. NOAA guidelines say people prosecuted in violation of the Marine Mammal Protection Act could face civil penalties of up to $11,000 and up to a year in prison.
Officials urge people to observe wild dolphins from a distance of at least 150 feet by land or sea and to avoid circling, entrapping or swimming with them, NOAA guidelines say.