Steep decline seen in giant sea turtles seen

Scientists were documenting stranded sea turtles on California’s beaches nearly 40 years ago when they noticed that leatherbacks — massive sea turtles that date to the time of the dinosaurs — were among those washing up on shore. It was strange because the nearest known population of the giants was several thousand miles away in the waters of Central and South America.

Their mysterious presence led researchers to a startling discovery. A subset of leatherbacks that hatches on beaches in Indonesia, Papua New Guinea, Vanuatu and the Solomon Islands were migrating 7,000 miles across the Pacific Ocean to the cold waters off the U.S. West Coast, where they gorged on jellyfish before swimming back. The epic journey stunned scientists.

“There are birds that go farther, but they fly. There’s a whale shark that might swim a little further, but it doesn’t have to come up for air. This animal is actually pushing water all the way across the Pacific Ocean,” said Scott Benson, an ecologist with the National Oceanic

and Atmospheric Administration’s fisheries service in Monterey, who has studied the turtles for decades. “It’s just a majestic animal.”

But now, just as scientists are beginning to fully understand the amazing odyssey, the turtles are disappearing — and fast.

In less than 30 years, the number of western Pacific leatherbacks in the foraging population off of California plummeted 80% and a recent study co-authored by Benson shows a 5.6% annual decline — almost identical to the decline documented thousands of miles away on nesting beaches. About 1,400 adult females were counted on western Pacific nesting beaches, down from tens of thousands of turtles a few decades ago, and there are as few as 50 foraging off California, Benson said.

If nothing changes, scientists say, the leatherbacks — creatures that can weigh half as much as a compact car and have 4-foot-long flippers — could be gone from the U.S. West Coast within three decades, a demise brought on by indiscriminate international fishing, the decimation of nesting grounds and climate change.