Researchers encounter rare, 1,419-pound leatherback sea turtle off California coast –

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Capturing and tagging a 1,419-pound leatherback sea turtle, it turns out, is a delicate operation.

In mid-October, after an airplane crew first spotted its green-black form in a patch of sea nettles 5 miles off Half Moon Bay, the chartered research vessel Sheila B. approached the giant marine reptile slowly from behind. Standing at the bow was veteran sea turtle tagger Scott Benson, holding a large hoop with an equally large net attached to it.

“We try to be really sneaky about this,” said Benson, marine scientist for the National Marine Fisheries Service. “We have to have it lined up perfectly so that the boat and the turtle are all going in exactly the same direction.”

With the boat and turtle aligned, Benson managed to encircle him with the hoop and enclose him in the net. Once he was secure, Benson and other researchers looped a rope around the turtle’s shoulders to gently guide him onboard, through specially designed hydraulic doors at the bow.

Benson has spent two decades studying endangered Western Pacific leatherbacks, which migrate 6,000 miles from Asia to devour up to a third of their weight in jellyfish along the California coast in summer and fall. More recently, he’s had the extra job of reporting their presence in Dungeness crab fishing zones to the state because of new rules that protect the animals from risk of entanglement in fishing gear.

The commercial crab season, due to start Monday, was delayed indefinitely after Benson and others observed leatherbacks and whales between Point Arena in Mendocino County and Monterey Bay last month.

Researchers tracking endangered Pacific leatherback sea turtles came across the same giant reptile twice in five years, this time in October near Half Moon Bay. George Shillinger of Upwell is on the far left, and Scott Benson of National Marine Fisheries Service on the far right.

Researchers tracking endangered Pacific leatherback sea turtles came across the same giant reptile twice in five years, this time in October near Half Moon Bay. George Shillinger of Upwell is on the far left, and Scott Benson of National Marine Fisheries Service on the far right.

Provided by National Marine Fisheries Service

Leatherbacks were around when dinosaurs walked the Earth, yet most Californians were perhaps unaware of their presence until they impacted the crab fishery. Only 55 now return to state waters to forage, according to Benson. Unlike whales, the prehistoric-looking creatures with a soft carapace and leathery skin are extremely difficult to spot from a boat.

The turtle Benson captured last month was the heaviest he’d ever encountered, weighed on a scale designed for cattle they installed in the boat. He had eaten so well that his shoulders and neck bulged with fat, and the ridges in his carapace had filled out. Even more surprising: Benson recognized him as Bumpy, an animal he and researchers had caught in 2016 and nicknamed for marks on his carapace that indicated a ship injury.

“The population is declining and fairly quickly. So how many times are we going to get to see some animal after it goes back and forth across the ocean a few times?” he said. “It’s very encouraging to see just the survivorship that this animal has.”

Leatherback sea turtles are protected under the federal Endangered Species Act, and the distinct population that forages off California, called the Western Pacific leatherback sea turtle, was added to the state’s endangered species list last month. That population has declined by 80% in 30 years, according to a report Benson coauthored in Global Ecology and Conservation, and faces a number of threats, including ship strikes, illegal poaching and loss of nesting habitat in Indonesia, the Solomon Islands and Papua New Guinea. The other population, called the Eastern Pacific leatherback sea turtle, nests from Baja Mexico to Costa Rica.



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