A woman walking along a California beach reported witnessing a man and his daughter mutilating the carcass of a dead seal, raising concerns about illegal activity and marine mammal protection laws.

Rashelle Diaz said she and a friend were enjoying a walk at Point Pinos Beach in Pacific Grove when they noticed a man and a younger lady bent over, sawing or hacking away at something.

Diaz said “he was decapitating a seal he had already skinned, and separated the skull from the body”.

Diaz confronted the man, informing him that his actions were illegal.

“90 per cent of the locals in Monterey are aware of that … you cannot go near a seal alive or dead, it’s the law,” she said.

The man claimed he had a permit for marine biology research, but Diaz noted he lacked proper safety equipment and identification.

“This man is in flip-flops, huge hunting filet knife. You know, he’s got a hoodie on, some camo shorts. Not professional looking at all.”

Despite her warnings, Diaz said the man continued his actions and left with a seal skull in a plastic bag.

The Monterey Bay National Marine Sanctuary emphasised the importance of not possessing any part of a marine mammal, dead or alive.

Milos Radakovich from the sanctuary said: “People get this thing about getting a piece of marine mammal. It’s not often you see it. And, of course, it is highly illegal.”

In the state of California, possessing parts of marine mammals such as baleen, fins, hair and bones requires a research or educational permit.

For the general public, possessing any part of a marine mammal could lead to serious consequences.

Advocates recommend contacting the Moss Landing Marine Lab if you encounter a dead marine animal.

“The Moss Landing Marine Lab should be called. If there’s a dead animal, they will pick them up and necropsy them. Try to evaluate, possible cause of death or whatever it is,” Radakovich said.

Diaz contacted authorities, but without a licence plate for the man’s vehicle, no further action could be taken.