MONTEREY — California’s Central Coast hosts a menagerie of marine life, from sea nettles to swordfish. And, just like on land, marine scientists say, there are seasonal visitors: Leatherback sea turtles regularly stop by between May and November, though their numbers are shrinking.
Leatherback sea turtles roam across the Atlantic, Pacific and Indian oceans on migratory journeys between nesting sites and feeding grounds. In the Pacific, some aim for California’s Central Coast, between the Russian River and Monterey Bay, to feast on the jellyfish that live there. Now, though, there are fewer leatherback visitors to California’s waters than in years past. Western Pacific leatherbacks — the group that includes the turtles that visit California — are critically endangered, thanks to accidental capture, egg harvesting, and beach development and erosion.
But there are some things we can do to help, according to Scott Benson, a marine ecologist at the National Oceanic and Atmospheric Administration based at Moss Landing Marine Laboratories.
“This comes down to our behavior, the things we choose to buy,” Benson said in a seminar on Saturday. “It’s in our hands.”
Benson’s lecture was part of Whalefest Monterey, an annual event hosted by Monterey’s Fisherman’s Wharf Association. This year’s festival took place on Saturday and Sunday.
“A lot of people live near the ocean, look at it every day, but don’t understand what’s going on underneath,” said symposium program manager Antoinette Saylor. The goal of Whalefest Monterey is to change that, she said, by presenting educational booths and activities and showcasing marine research.
Instead of a hard shell, leatherback sea turtles sport a flexible carapace of cartilaginous plates that fit together like jigsaw-puzzle pieces, Benson said. The leatherbacks that visit California begin their lives as silver-dollar-size hatchlings on the beaches of Indonesia, Papua New Guinea and the Solomon Islands, and can grow to weigh up to 2,000 pounds as adults, Benson explained. While adult leatherbacks tend to follow groups of jellyfish, the ecologist noted that young turtles get pushed around by ocean currents, and many die after ending up in areas where food is scarce.
Those that find themselves in places with plentiful supplies of jellyfish — including the Central Coast of California — will remember that bounty in future years and return to it between trips back to the western Pacific to breed.
That cross-ocean odyssey takes about a year, Benson said. And it’s during that crossing that the turtles face one of the biggest threats to their survival: hooks and nets meant for other species, especially swordfish. Humans also hunt leatherback eggs and adults directly, Benson said, and the loss of nesting sites to beach development and erosion — exacerbated by rising sea levels — has driven Pacific leatherbacks to being critically endangered.
The population has dwindled to about 1,400 adults, according to the International Union for Conservation of Nature. At one major nesting beach in Indonesia, the number of leatherback nests declined by about 78 percent between 1984 and 2011. The number of leatherbacks visiting the Central Coast each year is dropping at a similar rate, Benson said, and it was not high to begin with: In the 1990s, an average of 180 leatherbacks visited California each year.
The U.S. has tried to reduce the danger of accidental capture by limiting fishing in critical areas. That means fishing for swordfish in the U.S. is safer for western Pacific leatherbacks than in other countries — fewer turtles are accidentally killed, Benson said. Because of that, one way to help protect the species is to avoid buying swordfish that’s not fished in the U.S.
Diana Guerrero, of Pacific Grove, who attended the seminar, said she hadn’t realized how frequently leatherback sea turtles ply the waters of California’s Central Coast. And at restaurants, she said, “I always ask where the seafood comes from.”
Still, a leatherback turtle “doesn’t care whose political waters it’s in,” Benson said. “This is going to require an international effort if we are going to save these animals.
“They are ocean ambassadors,” he added. “They connect us to the rest of the Pacific Ocean.”
Contact Emily Benson at 408-920-5764. Follow her at Twitter.com/erbenson1.
