A sea lion suffering from gunshot wounds to the head has been taken to the Vancouver Aquarium Marine Mammal Rescue Centre for treatment.

The aquarium says this the second time in the span of 18 months that it has responded to such an incident.

It says in a news release that on Thursday a team of seven people went to a beach on the west coast of Vancouver Island, where an adult male Steller sea lion had been reported unresponsive but alive for several days.

Megan Strobel, a veterinary fellow at the aquarium, says preliminary exams show at least one bullet lodged in its skull and that the animal is possibly blind so it won't be able to live in the wild.

At about eight to 10 years old, the aquarium says the sea lion weights between 300 and 350 kilograms, which is considered underweight for a healthy adult male of its species.

Martin Haulena, head veterinarian at Vancouver Aquarium, says shooting the sea lions is a serious animal welfare issue.

"It is unacceptable to shoot sea lions," he says. "Based on his body condition, this individual has been suffering for many weeks."