Five people died after a whale-watching boat with 27 people on board sank off Vancouver Island and a rescue mission was hunting through the night, Canadian authorities said.

The vessel made a distress call late on Sunday afternoon on what was a clear and sunny day in the tourist community of Tofino, a popular destination for whale-watchers on Canada's West Coast, the Joint Rescue Coordination Centre said.

British Columbia Coroner spokeswoman Barb McLintock said five were dead so far.

The boat was partially submerged 12 nautical kilometres west of Tofino. 

Tofino's mayor described the mood in the town as tense but commended residents for their aid in the rescue effort.

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

Valerie Wilson, a spokeswoman for the Vancouver Island Health Authority, said 18 people were taken to Tofino General Hospital and were listed in stable condition.

Of those 18, she said, three were transferred to other hospitals. Some of the 15 who remained in Tofino have already been discharged, she said.

"There may be other discharges through the evening," she said. She did not have any fatality numbers.

Search and rescue operation

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

Boats from the nearby Ahoushat First Nation arrived first on the scene, said aboriginal Councilor Tom Campbell. He was on the waterfront and watched as rescue personnel brought several survivors ashore.

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

Campbell said his cousin pulled at least eight people from the water into a rescue boat.

John Forde, who runs The Whale Centre, another whale-watching operation, responded to the call for help and was told the search was 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 time dragged on without finding more survivors.

The ship that went down was the 20-metre Leviathan II, operated by Jamie's Whaling Station, Forde said. He said he had no idea how it could've sunk.

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

Forde said Jamie's Whaling Station was one of the first of its kind off Vancouver Island and had been around for many years.

Jenn Hamilton, a spokeswoman for British Columbia Emergency Health Services, said five ambulances were dispatched and several off-duty paramedics went to the dock to help.

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

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

Tofino fishing guide Lance Desilets said at least 12 rescue boats were already out on the water when he arrived on the scene.

"I saw a lot of personal belongings, a long diesel slick and the top 10 feet of the Leviathan II sticking out of the water," Desilets said. "It's a sad day for our community and the search and rescue people are doing the best that they can."

Joe Martin, a member of the Tal-o-qui-aht tribe, was near the dock when rescue boats went out.

The ship was on the far side of Vargas Island in Clayoquot Sound, an area that Martin said can get really rough, but was not on Sunday.

"It wasn't even blowing hard," he said. "This is the largest boat in Tofino and I was really surprised that it went down."

Source: Agencies