Two people are dead and another three are in stable condition after their 8.5-metre-long catamaran sank in the waters northwest of Tofino, B.C., off Vancouver Island.

A distress call came in around 1:20 p.m. PT on Sunday. According to the Joint Rescue Centre in Victoria, five people were in the water until 2:50 p.m. off Bartlett Island near Vargas Island, which is northwest of Tofino.

It could not confirm if the victims were wearing survival suits or life jackets.

Sub-lieutenant Melissa Kia of the rescue coordination centre said the mayday call came from a person aboard the vessel.

Moderate to rough seas

The person who made the call said the vessel was taking on water and those aboard were abandoning it.

Kia said the waters off Bartlett Island were described as moderate to rough, with average water temperatures between eight and 10 degrees this time of year.

Pilots from the Atleo River Air Service, along with pilots from Tofino Air, flew planes to the area to look for the victims. The pilots were the first to spot them.

"We had an airplane that was doing tours and we postponed the tour and went out," said Jason Bertin, operations manager for Atleo River Air Service.

A helicopter and plane also flew to the site from CFB Comox. The Canadian Coast Guard dispatched vessels to help as well.

The victims were rescued minutes later by two privately-owned boats, Kia said.

Survivors cold but stable

Coast Guard spokesperson Dan Bate said the boats linked up with the coast guard, and an off-duty paramedic provided CPR to one passenger while a Coast Guard Rescue Specialist tried to resuscitate another.

He says all five people were taken to shore Sunday afternoon, but health officials later confirmed that two of them had died.

Bate said the other three passengers were cold but in stable condition on Sunday evening.

Bate said in a release that the catamaran was a, "fishing vessel engaged in halibut fishing off Bartlett Island."

The catamaran has not been recovered, said Kia. It might not be, depending on the depth of water where it went down, she added.

She said the rescue coordination centre does not know the cause of the sinking.

Bertin said the vessel was located in waters "very close" to where the whale watching vessel Leviathan II capsized in October 2015 with 27 people on board. Six people died in that incident.