03/12/2014 21:08 EDT | Updated 05/12/2014 05:59 EDT

Sea lions rescued from slow death in Fanny Bay, B.C.

A Vancouver Aquarium marine mammal rescue team, in partnership with Fisheries and Oceans, has successfully disentangled California and Stellar sea lions spotted on log booms in the Fanny Bay area of Vancouver Island.

Over two days, aquarium staff says the team managed to use darts to immobilize several animals, including one that was tangled in plastic packing strap.

Aquarium head veterinarian Martin Haulena says they are seeing sea lions getting wrapped up in all sorts of ocean debris more often.

This rescue effort, which was filmed by the aquarium, was no different.

"It's a packing strap," says Haulena in the video, while looking at the injured sea lion. "Those are becoming the most common injury we see with entanglements around here."

The animals swim into the discarded plastic and, in most cases, are destined to die a slow and painful death.

'Rescue is tough and takes planning'

To rescue the animals, aquarium staff first had to tranquilize the animals with a special dart gun.

"I like to be around 60 to 70 feet, a little closer if possible," says Haulena. "We have a very nice dart gun. It's a very expensive Danish gun and it's very very accurate. But I'm very conservative, especially when working around groups of animals."

The video shows Haulena firing the dart gun, then cutting the deadly strap off of one of the sea lions.

"We've taken blood, looked for exposure to different disease, also looked for signs of inflammation on him," he says. "We've scrubbed out the wound as well as possible. It does look nasty but they're really good healers as long as you can get rid of that problem."

Haulena waits to make sure the sea lion comes out of its sedation, and then it goes back in the water hopefully to make a full recovery.

Disentangling technique is new and rare

Haulena is one of only a few veterinarians in the world — and the only one in Canada — who has experience immobilizing sea lions with an anaesthetic drug delivered by a dart.

The Aquarium says it took 15 years to develop an effective combination of drugs and protocols to safely dart sea lions and remove entangled gear.

Last fall, Haulena and marine mammal consulting biologist Wendy Szaniszlo, along with a large Vancouver Aquarium crew, whale watch operator Brian Gisborne, DFO, and Parks Canada, successfully disentangled two animals for the first time in the Barkley-Clayoquot region.