An Auckland man who leapt from a boat into the water near two orcas in what appears to be an effort to "body slam" the animals has been fined by the New Zealand Department of Conservation (DOC).
A video shared to Instagram in February shows the man jumping onto an adult male orca and a calf that were swimming near the vessel off the coast of Devonport, Auckland.
At one point in the video the man can be heard yelling "I touched it" and "did you get it?"
A group of people aboard the vessel can be heard laughing and cheering as they watch and film the situation.
The DOC said the actions on video seemed to be a deliberate attempt to touch or "body slam" the orcas, and displayed a "shocking and stupid attitude to protected marine mammals".
Concerned members of the public notified the DOC of the incident, and the department was later tipped off to the video posted online.
The man was then identified and handed a $NZ600 ($550) infringement fine.
DOC Principal Investigation Officer Hayden Loper said the 50-year-old Auckland man showed reckless disregard for his own safety and that of the animals.
"The video left us genuinely stunned," Mr Loper said.
"As well as the initial attempt to dive onto the animal, the man stays in the water and then swims toward it again in a second attempt to touch it.
"This is stupid behaviour and demonstrates a shocking disregard for the welfare of the orca. It is extremely irresponsible.
"Orca are immensely powerful animals, and this really could have ended horribly – with either the startled whale being injured, or the man responsible being harmed by the aggravated animal."
The man's actions were a "very clear breach" of laws protecting marine mammals, Mr Loper said.
Orcas are classified as whales under New Zealand conservation legislation, and it is illegal to swim with whales, or disturb or harass any marine mammal, he said.
Mr Hayden said the case was the third in recent years where social media content had led to a "successful prosecution" for the DOC.
There have been incidents in which wild orca, which are apex predators, have been perceived to have attacked humans, the DOC said.
Any sudden moves near them significantly risk the chance of people being harmed.
In a recent incident off the coast of Spain, orcas sank several small vessels.
Between 150 and 200 orcas are estimated to live around the waters of New Zealand, and their status is classified as "nationally critical".
Boat strikes and noise pollution from vessels pose a threat to the species, the DOC said.