Boaters in Alaska saw a strange sight on Thursday: A six-meter-long killer whale lay on the shore, stuck in a crevice.

Someone on a boat spotted the orca on Prince of Wales Island near the coast of British Columbia, Julie Fair, a spokeswoman for the National Oceanic and Atmospheric Administration, said in an email.

The first call to the U.S. Coast Guard came around 9 a.m. about the whale stranded on the rugged coast at least three feet above the tide line.

Soon, Chance Strickland, the captain of a private yacht in Alaska, and his crew anchored and came ashore to spray the whale with sea water. The fog kept the whale cool and chased away birds that had gathered in the trees nearby, waiting to eat the orca alive.

Mr Strickland and his crew hoped the 13-year-old whale would swim and return to the sea at low tide that afternoon. Mr. Strickland could hear the orca calling the killer whales swimming in the area.

“I don’t speak much whale, but it didn’t seem like that much,” he said.

People on other boats stopped with water and buckets to water the orca. Mr Strickland and his crew gave the whale a wide berth in case it fluttered around, he said.

“Tears came out of my eyes,” he said. “It was pretty sad.”

Mr Strickland left the island after wildlife officials came to relieve him and his crew, he said.

The tide finally came around 2 p.m. local time, NOAA said, and the seawater eventually rose so high that the whale, known as the T146D, swam again.

“It moved a little slowly at first and meandered a little before swimming away,” said Ms. Fair.

It was a happy ending for the whale, which returned to the sea about six hours after being discovered on the shore. The Canadian authorities confirmed that the orca was a Bigg killer whale of the “continuous west coast” population.

The stranding occurred just one day after a strong 8.2 magnitude earthquake off the coast of Southwest Alaska. However, the quake, the largest in the country in 50 years, did not cause the whale to become stranded, NOAA said.

Toa, an orphaned baby killer whale, suffered a different fate than T146D after washing ashore in New Zealand this month. Although conservationists fed the whale in a makeshift pool and volunteers searched the coast for days to find Toa’s family, the orca eventually died.

In one of the world’s largest whale strandings ever recorded, Australian rescuers last year rescued 108 of the 470 whales that landed on a wide, secluded sandbar in the rugged harbor of Macquarie, Tasmania.

Live whale stranding is uncommon, but does happen from time to time, experts said.

Five whales, including T146D, have been recorded as stranded on the west coast in the past two decades, said Jared Towers, a researcher with Fisheries and Oceans Canada, a government agency, and Bay Cetology, a killer whale research organization.

“These whales would hunt seals or sea lions and just make a mistake and basically get stuck and then the tide would go out,” he said.

Every whale but one survived stranding, he said. While a stranded orca is on the shore, it is at risk of overheating, being crushed by gravity, or being attacked by birds or bears.

Mr Towers said it was difficult to say how long the whale would have survived if the tide hadn’t come. He said he heard about a whale that had waited 11 hours for the water to rise. Since T146D was still a teenager, his body was small enough not to be crushed by gravity, he said, adding that he survived the stranding with only superficial cuts and abrasions.

He said the whale may have been waiting for the tide to come in after getting stuck in the rocks. Instead, however, the tide fell, so that the orca was separated from other whales in the area for a few hours.

“There’s a pretty good chance it will meet you now, and it just leads a normal life after spending some time out of the water,” he said.