A rare sighting of the endangered leatherback turtle off the B.C. coast is an opportunity to celebrate — but also to reflect on the danger of plastic waste in the oceans, a marine biologist says.

Earlier this month, two Vancouver Island men captured photos of the enormous sea turtle. It was one of fewer than 135 sightings recorded in B.C. waters since the 1930s.

The leatherback is one of the largest reptiles on the planet and can grow to the size of a Smart car. Instead of a shell, the turtles have a thick, collapsible leather-like back that allows them to dive to extreme ocean depths of up to 1,270 metres.

The turtles, which travel from Indonesia to feed on jellyfish, have seen their populations decline drastically in recent years, in part due to frequent entanglement in plastic pollution, according to the the Department of Fisheries and Oceans.

Turtles confuse balloons with jellyfish

In Jackie Hildering's experience, marine species are often the first to bear the brunt of environmental problems and leatherbacks are no exception, as many are found with plastic in their stomachs.

Hildering, a researcher with the Marine Education and Research Society, said many people in B.C. may not even know the species exists in local waters, but that even small actions such as releasing a balloon into the air without thinking about where it might land can have an impact on the turtles' survival.

"One of the powerful things to realize is that they can't discern plastics and balloons from their jellyfish prey," she told Jason D'Souza, host of CBC's All Points West.

Leatherback turtles in Canada have been designated as an endangered species under the Species at Risk Act. The species has lost 70 per cent of its numbers in the past 15 years.

Tracking jellyfish

A major challenge in tracking and restoring leatherback populations in B.C. waters is first tracking their food source, the jellyfish, said Lisa Spaven, a scientist with the DFO's Pacific Biological Station.

Marine biologists rely on fish surveys to include jellyfish population data, including density and location. Jellyfish are hard to track and scientists are still figuring out whether leatherbacks prefer areas with a high density of small jellyfish or a low density of large jellyfish, Spaven said.

Hundreds of jellyfish float beneath the surface off Canada's West Coast. They are the food source that draws the leatherback turtle across the ocean from Indonesia. (Keith Holmes/Hakai Institute)

"We're still trying to get a handle on the currents and where the jellyfish are. There's a lot of work yet to be done," she said.

Funding for leatherback conservation was not approved by the DFO this year according to Spaven but her department continues to carry out habitat protection work in Indonesia, where nests are at risk from predators such as wild pigs.

'​Smallest needle in the biggest haystack'

Former Vancouver Canucks defenceman Willie Mitchell and photographer Jeremy Koreski spotted the turtle on Aug. 6 just west of Tofino, B.C., and forwarded their photos to Hildering.

Hildering said the men recognized the turtle as a leatherback but, like many in B.C., did not know how important the sighting was.

"​I don't think they knew that I would fall off my chair when they sent the photos, I don't know that they knew they found the smallest needle in the biggest haystack," she said.

Leatherbacks are "living dinosaurs" that "belong in B.C. waters," Hildering said, and their presence is a reminder of the wide variety of species B.C. coastal waters should support under optimal conditions.

"It's a testament to how rich our waters are supposed to be."

With files from All Points West

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