TOFINO, B.C. -- A harrowing rescue operation off the west coast of Vancouver Island was underway Sunday night where a whale watching ship with 27 aboard board sank sending those aboard into the water, some to their deaths.

Lt.-Cmdr Desmond Craig, a spokesman with the Joint Rescue Co-ordination Centre said four people were pulled out of the water without vital signs, but he couldn't confirm if those people had died.

Both British Columbia's Emergency Health Services agency and the mayor of Tofino, Josie Osborne, said at least three people were dead

"Everybody's heart is just breaking for what's going on here and wanting to be as helpful as possible," Osborne said in a phone interview late Sunday.

Coast Guard vessels and search and rescue aircraft were searching for people on the boat who were unaccounted for. The helicopter and aircraft being used in the waters off the community of Tofino had equipment to search in the darkness.

"The Cormorant helicopter has bright lights and the Buffalo aircraft can launch flares so with that and the vessels on the water...that's enough to cover the area," Craig said.

Craig could not immediately say how many people on the boat remained unaccounted for.

The rescue centre said the vessel made a mayday call late Sunday afternoon on what was a clear and sunny day in the tourist community.

Boats from the nearby Ahoushat First Nation were the first on the scene, said aboriginal Coun. Tom Campbell.

He was on the waterfront and watched as rescue personnel brought several of the survivors ashore.

"Their looks tell the whole story," he said on the phone from Tofino. "You can't describe looks on people that are lost. They look totally lost -- shocked and lost."

Campbell, who wasn't on the water, said he cousin pulled at least eight people from the water into a boat on Sunday afternoon.

John Forde who runs The Whale Centre, another whale watching operation in the community, responded to the call for help and was told they were looking for four or five missing people.

"It's a pretty sad situation when you're doing a grid pattern to an area hoping to see something," he said adding that it didn't look hopeful as the time dragged on without finding survivors.

Campbell said the First Nation was holding a meeting to discuss launching further rescue operations in the morning.

Brandon Hilbert from Tofino Water Taxi said local companies all pitched in to help in the rescue effort.

The ship that when down was the 20-metre Leviathan II, operated by Jamie's Whaling Station, Forde said.

He said he had no idea what might have happened.

"Over the course of a season and years we take out thousands and thousands of people on these trips in conditions similar today. I have no idea what the issue was or what actually happened.

Forde said Jamie's was one of the first such whale watching operations on the west coast of Vancouver Island and had been around for many years.

When contacted an employee of Jamie's who answered the phone would not take any questions.

"I hope you can understand that all of our focus and energy is on the passengers and crew right now and we don't have any information and we will be releasing it when the time is appropriate," the unnamed person told The Canadian Press.

This isn't the first accident for the whale watching company.

In 1998 one of their vessels capsized during an excursion, sending all four people on board into the water. The operator and one of the passengers died.

The Transportation Safety Board confirmed it was investigating Sunday's incident.