Green sea turtles are not built for life in the chilly North Pacific, but that's where one found itself on Saturday — washed up and hardly moving on a beach in Pacific Rim National Park Reserve near Ucluelet, B.C.

The endangered turtle — hypothermic and stunned by the cold — was spotted by a park visitor near the high-tide mark on Wickaninnish Beach, said Jennifer Yakimishyn, a resource management officer with Parks Canada.

Park staff "treated it like a patient," gently lifting the hefty reptile on a stretcher made of tarps and blankets, to transport it to safety for treatment at the Vancouver Aquarium, she said.

The turtle arrived in critical condition but is "on track" for improvement, said Dr. Martin Haulena, the aquarium's head veterinarian.

Green sea tutle

The rescued turtle at the Vancouver Aquarium on Monday, where its temperature is being carefully monitored during warming. It's also received antibiotics, fluids and care for wounds on its shell. (Meera Bains/CBC)

Treating a cold turtle

The treatment? Warming up, slowly and carefully.

"Reptiles are cold-blooded and they completely depend on their external environment to control their body temperature," said Haulena.

So for an animal that normally lives in warmer water off Mexico or Hawaii, the cooler B.C. waters led to hypothermia, also known in reptiles as "cold-stunning," he said.

"Everything slows down: heart, respiration rates. They can't swim. They can't forage. They get weaker and weaker."

The turtle was admitted for treatment with a body temperature of 11.2 degrees Celsius and is being warmed just a couple of degrees a day, until it reaches normal at 20 degrees or more, the Aquarium said.

"The sea turtle is doing as expected. When these guys strand, whether it's the sea turtle or the fur seal, they don't strand because they're healthy, by any stretch."

The Aquarium is also treating an emaciated Guadalupe fur seal "in very critical condition" that was rescued near the same beach last Wednesday. That species is normally found off Mexico's Guadalupe Island.

Guadalupe seal

This Guadalupe fur seal, native to Mexico, was rescued off the coast of Vancouver Island last Wednesday. (CBC)

El Niño visitors?

It's not clear why the turtle travelled so far north, but Haulena said strandings like these are more common in El Niño years, when a temporary shift in weather patterns brings warmer water to the coast of B.C.

"Those are species we associate with slightly warmer water, more tropical areas," said Haulena.

Green sea turtles can weigh up to 150 kg and are found around the world in tropical and sub-tropical waters. The females migrate large distances — hundreds or thousands of kilometres — to lay eggs on the same beaches where they were born, according to the U.S. National Oceanographic and Atmospheric Administration.

It's not clear whether the turtle found last weekend is male or female, the Aquarium said.

Sea turtles have stranded in the Pacific Rim park before, said Yakimishyn, including two green sea turtles in 2011 that did not survive.

She encourages any visitor that sees a stranded animal to report it but stay away.

"Everybody wants to go see it, but it's always important to keep your distance, because these are stressed animals that may also carry disease," she said.

Green Sea turtle

Green sea turtles are found worldwide in tropical and sub-tropical waters and can grow to 150 kg. They are considered endangered worldwide by the International Union for Conservation of Nature. (Shutterstock)

With files from Meera Bains