Rescue personnel mount a search for victims of a capsized whale-watching boat park on a wharf in Tofino, B.C., Oct. 25, 2015.
Britain's Foreign Office has confirmed the five victims of Sunday's whale-watching accident were British citizens.
The whale-watching boat carrying 27 sightseers sank late Sunday, apparently after hitting rocks near Tofino, killing five people and sending 18 others to hospital.
"It is with deep sadness that I can confirm five British nationals have lost their lives when the whale-watching boat they were on sank off Western Canada on Sunday," Foreign Secretary Philip Hammond said in a statement.
"My thoughts are with the family and friends of all those affected by this terrible accident. Consular staff in British Columbia are supporting the family members of those who have died and we will remain in close contact with Canadian authorities as further information becomes available."
Local fishermen raced to the reef at the first sign of trouble Sunday and were credited with rescuing many of those struggling in the cold water. But after hours of searching, the mission was declared concluded with one person unaccounted for late Sunday night. That case was turned over to the RCMP as a missing persons investigation, said a recorded update from the joint rescue co-ordination centre.
Among the injured, three were taken by ambulance to other hospitals on Vancouver Island and were in stable condition. The remaining 15 stayed at the Tofino hospital, and some were discharged, said Val Wilson, a spokeswoman for the Vancouver Island Health Authority. She said she did not know what the injuries were.
Fishing guide Lance Desilets was shocked when he got to the accident site.
The Leviathan II, a 20-metre-long vessel used by Jamie's Whaling Station and Adventure Centres to take tourists on nature cruises around Clayoquot Sound, was partially resting on the bottom – and the surface of the water was covered with floating, personal debris.
"There were purses, jackets, all kinds of stuff on the water ... It's terrible. I'm beside myself," he said.
"It was brutal."
The tour boat's operator thanked first responders for their work and said his company was co-operating with investigators.
"It has been a tragic day. Our entire team is heartbroken over this incident and our hearts go out to the families, friends and loved ones of everyone involved. We are doing everything we can to assist our passengers and staff through this difficult time," Jamie Bray, owner of Jamie's Whaling Station and Adventure Centres, said in a statement.
Joe Martin, a member of the Tal-o-qui-aht First Nations, said members of his family were among the first to arrive at the scene of the accident.
He said Marcel Martin, Carl Martin and Don Williams Jr. were coming back from a fishing trip when they heard emergency calls on the marine radio.
"They knew the Leviathan II had been near Plover Reef because they saw it earlier, and then they couldn't see it anymore," he said of the whale-watching boat.
The three fishermen raced to the reef, and Mr. Martin said they told him they heard a whistle blowing and saw about nine people alive in the water, being helped into another rescue boat.
"They went to get two bodies out of the water and they were so close to the rocks they were getting washed up there themselves," he said. "They got two in and then a third body floated up. So they got three."
He said the experience had left the three men shaken.
"They are going to need some help [emotionally]," he said.
Marcel Martin said he didn't feel up to talking about it when contacted later.
The Transportation Safety Board of Canada said in a statement it is deploying a team to Tofino to investigate the accident.
Boats from the nearby Ahoushat First Nation were the first on the scene, said aboriginal Councillor Tom Campbell.
Mr. Campbell, who wasn't on the water, said his cousin pulled at least eight people from the water into a boat.
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.
Mr. Campbell said the First Nation was holding a meeting to discuss launching further rescue operations in the morning.
Mr. Desilets said he rushed to the scene as soon as he heard emergency broadcasts over the marine radio.
He added that when he got to Plover Reef, there were a dozen boats trying to help. Mr. Desilets said he pulled in what personal items he could find, then returned to Tofino.
Mr. Desilets, who runs Lance's Sport Fishing Adventures and is on the water constantly, said Plover Reef is a popular spot for tour boats to stop because of the marine life there.
"My guess is they were watching sea lions. I guess they got too close and hit the rocks," he said.
"It's rugged and rocky. There's quite a substantial tide change ... Waves were crashing against the rocks and the tide would have been pulling you out," he said.
Transportation Safety Board spokesperson Julie Leroux said three to four investigators are en route to Tofino and expected to arrive later today. Some are from Ottawa and the others from the B.C. regional office.
"Once the investigators are on site, they will collect data. They will conduct interviews with the crew members and the passengers. They will look at the weather conditions at the time of the accident. They will ask for the maintenance history of the vessel," she said.
Boats operated by Jamie's Whaling Station were involved in two previous accidents, including one in which two people died in the same area.
In March 1998, a whale-watching vessel, the Ocean Thunder, was near Plover Reefs when it was swamped by large waves which threw all four people onboard into the sea.
One passenger and the operator, who hadn't fully zipped his floater suit, drowned. The two survivors suffered from hypothermia.
The Transport Safety Board investigation concluded that "the operator did not fully appreciate the conditions the boat would meet at the time of the accident in the turbulent waters in the vicinity of reefs."
Two years before, in August 1996, the Sharp Point, another vessel owned by the same company, was on its way to pick up passengers when it ran aground while at full cruising speed on the north shore of Flores Island.
The operator, who suffered multiple head injuries, had probably fallen asleep at the helm, the safety board concluded.
"Because excursion-craft owners wish to optimize the tourist market during the whale-watching season, these craft are operated from early morning until late daylight hours. At such times, the single operator is taxed to the limit and can be overcome by fatigue and the monotony of the operation," the investigation report said.
Prime-minister-designate Justin Trudeau said in a statement he was "shocked and saddened" to hear of the sinking of the Leviathan: "We thank all those, including our search and rescue officials, who responded swiftly with courage and professionalism. I know firsthand of this coastal area's natural beauty and the many people who visit here from all around the world. My thoughts and prayers are with the passengers, the crew, and their families at this most difficult time. We will continue to offer them support in the days ahead."
The whale-watching company was founded by Mr. Bray, who was one of the pioneers of what has become a popular tourist pastime.
Mr. Bray started the business in 1982, going from 400 whale-watchers to 12,000 per year in the early 1990s, according to a travel article published in an Ontario regional newspaper.
Many of Tofino's whale-watching excursions take place on smaller inflatable Zodiac boats, but the Leviathan II used by Jamie's Whaling Station accommodates many more passengers.
Reached at his home in Port Alberni, Bruce Adams, a captain who has worked for Mr. Bray's whale-watching company, said he was "heartbroken" by the news, and declined to comment further about what might have happened.
With reports from Greg McArthur and The Canadian Press
Editor's note: An earlier digital version of this story incorrectly stated the scene as Plover Point. This digital version has been corrected.