California has added the Pacific leatherback sea turtle to its endangered species list, guaranteeing more protections for a rapidly dwindling population.The California Fish and Game Commission voted Thursday to add the turtles under the state's Endangered Species Act. The world's largest turtle species have been on the federal endangered species list since 1973. But scientists now know more about how crucial California is to their survival, according to Catherine Kilduff, an attorney with the Center for Biological Diversity.A subpopulation of leatherback sea turtles hatch on beaches in Indonesia. Once fully grown, they swim nearly 6,000 miles (9,656 kilometers) to eat jellyfish off the California coast. Adult leatherback sea turtles weigh an average of 1,000 pounds (453 kilograms).Scientists say these sea turtles have declined by about 5.6% in California each year for the past three decades. About 50 sea turtles visit the California coast each year, compared to about 178 turtles in the 1990s, according to the Center for Biological Diversity.Adding turtles to California's endangered species list will make them a conservation priority for state agencies. It will also increase the state's cooperation with federal agencies to protect the sea turtle population.“Leatherbacks that forage for jellyfish off the California coast will now receive greater protection in our state from entanglement in fishing gear, giving them a better chance at survival,” said Todd Steiner, executive director of Turtle Island Restoration Network. “We are hopeful this action will put these ancient, gentle giants on a path to recovery.”