Cursed with succulent meat, green sea turtles have suffered an enormous decline since Europeans arrived in the Americas.

Sailors stacked them on their backs on ships, keeping them alive as a steady source of food during long voyages. Beginning in the 19th century, commercial fisherman sent thousands of them to Europe for soup. Early settlers walked the beaches to dig up their eggs.

The federal government declared green turtles an endangered species 27 years ago, imposing protection measures. And this year, a record number of the huge reptiles crawled up the beaches of southeast Florida, dug nests and laid eggs, according to draft government reports. While scientists remain concerned about the species' future, they say the increase may show that years of work to protect the turtles are finally bearing fruit.

"We may have more turtles out there than we've ever had before, at least in recent years," said Gary Popotnik, a biologist at the Merritt Island National Wildlife Refuge, where green turtles dug a record 206 nests along a six-mile stretch of beach. "I'm sure it's the protection measures."

In Broward County, researchers counted 255 green turtle nests, breaking the previous record of 200 nests in 1998, according to a draft report by Nova Southeastern University's Oceanographic Center, which monitors the nests for the county. In Palm Beach County, the number of nests hit 1,960, way up from the previous record of 1,278, according to the county's Department of Environmental Resources Management. Farther north, biologists report similar increases along the dark, undeveloped beaches that tend to attract the huge reptiles.

Biologists are cautious about drawing firm conclusions from the numbers. They say the increase could reflect weather changes, a temporary spike in the food supply or other factors that would offer no encouragement about the species' future. They note that the greens remain endangered, vulnerable to a host of natural and artificial threats.

"The population is still small," Popotnik said. "We could get hit by a hurricane in the middle of nesting season and take out all their nests. That's one of the reasons we can't let our guard down. They're a long way from being to full recovery. It will probably be decades."

Robbin Trindell, biological administrator of the Florida Fish and Wildlife Conservation Commission, said the cause of the increase is unclear but that it could well be the result of efforts to protect the turtles. Even poor countries, where sea turtles are a source of food, have imposed conservation measures.

"There's a lot more environmental awareness," she said. "Developing countries are working hard to protect their sea turtles."

Green turtles continued to be harvested in U.S. waters through the 1960s, until the federal government banned the turtle trade, she said.

Since then, the government has imposed several other measures to protect them. Fishing fleets in U.S. waters were required to install turtle-exclusion devices to prevent sea turtles from drowning in their nets. Beach barriers in many places were removed. Many local governments imposed lighting restrictions along beaches to prevent bright lights from disorienting hatchlings or scaring off females that want to lay eggs.

Green turtles grow up to 400 pounds and can live up to 70 years. They eat seaweed and other vegetation. Like other sea turtles, they crawl up on beaches at night to dig nests and lay eggs. But not much more is known about them.

"They're one of the great mysteries of nature," Popotnik said. "When they're not nesting, we're trying to figure out where they go."

The other species of sea turtles that nest in Florida, loggerheads and leatherbacks, showed decent numbers, but didn't break any records, according to officials in Broward and Palm Beach counties. But thanks to the increase in green nests, each county broke its records for total number of sea turtle nests.

Whatever the source of the increase, biologists are happy with what appears to be good news about an endangered species.

"It's quite a significant increase," said Carly Pfistner, environmental coordinator in Palm Beach County's Department of Environmental Resources Management. "We're incredibly pleased with that. Something is going on, but it's too early to say what it is."

David Fleshler can be reached at dfleshler@sun-sentinel.com or 954-356-4535.