A sea lion with a net around its neck and its mouth taped shut has been rescued in British Columbia.

A sea lion has been freed off the coast of Vancouver Island after becoming so entangled in a net that rescuers say it may not have eaten for weeks or months.

The Vancouver Aquarium Marine Mammal Rescue Society said in a statement that the complex operation at the Race Rocks Ecological Reserve was one of the most serious predicaments the team faced.

The rescue society says an adult male sea lion was spotted Oct. 20 with a gill net wrapped tightly around its snout, neck and inside its mouth, preventing it from feeding, resulting in severe injury and exhaustion.

After 48 hours of planning and coordination, the society’s chief veterinarian tranquilized the sea lion with a dart, after which it entered the water and was tracked by a drone operated by the federal fisheries department until it could be safely approached.

The mesh was embedded so deeply that standard instruments could not be used and surgical scissors were required to cut the tangle within 75 minutes, the statement said.

The society says the sea lion was given antibiotics, painkillers and sedatives were withdrawn before it was spotted swimming away and then pulled onto a rock “showing signs of recovery.”

The society’s senior manager Lindsay Akhurst says the rescue was one of the most heartbreaking but also rewarding she has been involved in.

“Even experienced rescuers were saddened by the scale of this animal’s suffering. The net was so tight and cut so deep into his neck that his mouth was completely closed,” she said.

“The sea lion couldn’t eat for weeks or even months. We knew we had to act quickly.”

Dr Martin Haulena, the society’s chief executive and chief veterinarian, stressed the importance of preventing such incidents.

“Rescue operations like this highlight the ongoing problem of marine debris. While we are grateful that this sea lion is recovering, we need to focus on preventing these entanglements from occurring in the first place.”