KEA'AU, Hawai'i — Police believe the flashing blue lights of a patrol car spooked a would-be sea-turtle poacher into abandoning his 150-pound prey by a Big Island roadside.

The female green sea turtle was protected by passers-by until officers from the state Department of Land and Natural Resources arrived. They later tagged and released the turtle into the Wailoa boat harbor.

"She was healthy, her shell was intact, and she was very responsive when we put her on the ramp," said John Kahiapo, aquatics education specialist for the department. "She crawled into the water and swam vigorously toward the open ocean."

Dead or alive, all sea turtles in Hawai'i are legally protected. Green sea turtles, also known locally as honu, are listed as a threatened species.

"Sea turtles have played important roles in the environment and culture of Hawai'i," said Peter Young, chairman of the department. "They are listed and protected under the U.S. Endangered Species Act and wildlife laws of the state of Hawai'i."

It's illegal to harass, disturb, harm, kill or keep sea turtles in captivity without a permit, or to sell any sea turtle parts or products, Young said.

The female turtle, estimated to be more than 20 years old, was first reported to Big Island police in Puna at 4:52 a.m. on July 28. Officers found the turtle next to the road near an entrance to Kea'au High School.

Police had been monitoring traffic near the school early that morning and suspect that the reptile had been discarded from a vehicle when someone coming up from the lower Puna beach area saw the officers' flashing blue lights.

The fines and penalties for harming or even disturbing a green sea turtle aren't light — adding up to a potential $12,000 and a year in prison on a first offense under state law alone.

Under state law, a first conviction brings a $250 to $2,000 fine or a prison term of up to a year, or both. On a second offense within five years, the fine goes up to a minimum of $500. There also is a $5,000 fine for each specimen of a threatened species knowingly killed or removed from its original growing location. An additional $5,000 administrative fine also can be levied for each plant or animal taken, killed, injured or damaged in violation of state law.

Federal fines range from up to $500 to $50,000 for each violation.

Once a valuable food source for Pacific islanders, the turtles get their name from the color of the fat under their skin. While their numbers have declined dramatically, researchers say there are promising signs of the species' recovery over the past several decades since protection began in 1978.