BENEATH the moonlight, as she slowly emerges from the sea, a loggerhead turtle cuts a mysterious figure on the foaming shoreline. On steamy summer nights from Virginia to Texas, thousands of these puzzling creatures are poking their scaley, barnacled shells out of the surf. ``It looks a little like an invasion of tiny army tanks,'' says Larry Woods, curator of the Juno Beach Turtle Museum here. He is on the beach at 7 o'clock each morning to make sure the nocturnal turtle visits have gone smoothly.
Digging their flippers in the sand, the loggerheads inch their 300-pound bodies across the beach to deposit some 100 leathery eggs the size of Ping-Pong balls in three-foot sand pits - their gift to the future. It is the only reason a turtle comes out of the water.
But not all is well with the turtle, Mr. Woods is quick to point out. Sea turtles have rapidly become an endangered species. From the Caribbean to the Atlantic, and from the Mediterranean to the Pacific, whole populations of these giant reptiles are disappearing.
It is a story of accident and exploitation, a clash with humans - and a phenomenally fast fall for a species as old as the dinosaur.
Sea turtles are most at risk during the summer when they swim ashore to nest. They get tangled in fishing nets and become easy prey for hunters.
At one time, the world's oceans were brimming with turtles. Centuries ago, ships' logs said the Caribbean was so full of them one could be guided toward an island by the clacking of their shells knocking together.
Earlier this century, ``you couldn't row a boat in front of nesting beaches,'' says Jim Richardson, a turtle expert at the University of Georgia. ``Turtles would kick the oars out of the oarlocks.''
No one knows exactly how many sea turtles exist today, since they are sea travelers. But on Mexico's Rancho Nuevo beach, where 40,000 Kemp's ridley turtles nested en masse on a single day in the 1940s, only 400 or 500 nest today. South Carolina's barrier islands have registered an alarming 26 percent decline in loggerheads nesting just in this decade, says Sally Murphy, the state's chief turtle biologist.
Georgia's Cumberland Island National Seashore, nesting beach for 150 turtles 25 years ago, gets only about 20 nesters a year now, Mr. Richardson says.
In Indonesia and Malaysia, hunters who once found their shores flush with quarry, must head out to sea. In the Maldives and Cayman Islands, wild turtles have literally vanished.
Recent efforts in the United States to rescue the sea turtle have spawned perhaps the biggest wildlife debate since the 1978 brawl over the snail darter and Tennessee's Tellico Dam.
The major turtle killer in US waters is the net of shrimp fisherman, according to environmentalists. After years of pitched debate between them and the shrimp industry, Congress bought the environmental argument - ordering shrimpers to put ``turtle excluder devices'' (TEDs) in their trawling nets. Legislators believed the step could save 12,000 turtles a year from drowning.
The regulation took effect May 1. But after massive civil disobedience by shrimp fishers, it was scrapped, at least temporarily. Atlantic fishermen on the whole complied with the regulation, but thousands of fishermen in the Gulf of Mexico are fighting it tooth and nail (see story at left).
Worldwide, the chief threat to the turtle is international trade. Sometimes legally, but often not, African, Asian, and Caribbean turtle hunters supply Asia's huge appetite for turtle-shell jewelry and turtle leather accessories. The eating of turtle eggs and meat has helped deplete populations, too.
``The sea turtle,'' says Michael Weber of the Center for Marine Conservation, with a sigh, ``is probably the most salable animal in the world. All its parts can be sold for meat, soup, or shell.'' It was not long after World War II that the turtle market began to grow out of control.
Japan is the motor driving international turtle trade. It consumes some 28,000 hawksbills - the turtles with the prettiest shells - a year for jewelry, hair ornaments, and eyeglass frames, reports TRAFFIC, an arm of the World Wildlife Fund that monitors trade in endangered species.
Japan's fondness for turtle-skin purses, shoes, and belts is almost as strong as that for jewelry. The trade has decimated Mexico's olive ridley and Pacific green turtle nesting colonies.
Some 23,000 more hawksbill and green turtles have been sold to Japan each year to be stuffed and hung as wall ornaments.
It is not as though the world has failed to notice the plight of the turtle. Japan reportedly is ending the stuffed-turtle trade under pressure. And there are some treaties and laws intended to help endangered animals. But so far, there has been little success enforcing the measures.
In the US, the Endangered Species Act, the prime animal protection tool, ``is strong on paper,'' says Michael Bean, chairman of the Environmental Defense Fund's animal protection program. ``The problems are with the willingness of the agencies responsible for implementing the legislation to use their authority effectively.''
TED regulations in the Gulf were enforced only about 2 of the 11 weeks they were in effect. Commerce Department spokesmen say suspension of the rule leaves time to develop a program that is enforceable. Environmental groups are concerned the action sets a precedent and ``punches a hole in the endangered species act for all wildlife,'' says Steve Moyer, a lobbyist for the National Wildlife Federation.
Some other countries also have laws - rarely enforced - to protect wildlife. But the chief international means for preserving turtles is the Convention on International Trade in Endangered Species (CITES), an agreement signed by 100 countries to limit trade in endangered plants and animals. The record on compliance is not good.
TRAFFIC has identified a number of major violators of the agreement's provisions on turtles. Indonesia, Hong Kong, Malaysia, Panama, Belize, Ecuador, Nicaragua, Honduras, Tanzania, and Kenya are engaging in large-scale turtle selling, TRAFFIC says. Dozens more violate CITES to a lesser degree, it says.
Jeffrey Canin, a biologist with Greenpeace, and other ecologists are especially worried about Mexico, which has not signed CITES, and Indonesia, perhaps the world's two most important turtle-nesting countries. Both have regulations governing wildlife, but reportedly are sliding backward on actual protection.
Environmentalists acknowledge it is difficult to tell third-world countries they should restrict turtle hunting. Turtles are a cheap, local source of food; one animal can provide a poor family's major source of income in a year. But ecologists insist that nations must learn to take fewer eggs and turtles today if they are to have any turtle supply in the future.
Seven turtle species still roam the seas, some in greater numbers than others. They range from the half-ton, jellyfish-eating leatherbacks, which explore earth's colder oceans, to the tinier 80-pound Kemp's ridleys, which stick mostly to the warm Caribbean. The worst off are the Kemp's ridleys and hawksbills, shallow-water lovers that forage in close proximity to man. The Kemp's has been so decimated that it has earned a place on the list of the world's 12 most endangered species.
Although the numbers of turtles continue to fall, there are rays of hope for them. Scientists are studying sea turtles more closely and are beginning to collaborate with scientists from other countries, a step considered essential to preserve such a migratory animal. They are trying to get turtles to nest on safer beaches.
In the US, an ambitious effort to create a sea turtle sanctuary is taking shape along a densely nested 20-mile stretch of Florida's Brevard and Indian River counties. The US House of Representatives has just set aside $3 million to begin acquisition. Biologists say the sanctuary is crucial to preserving the loggerhead turtle since, after Oman, Florida's east coast is the world's largest nesting ground for this species.
But it is also in Florida and other alluring vacation spots that the future challenges to sea turtles will be most acute, environmentalists predict. Dense developments along their balmy beaches already are crowding turtles out of traditional nesting sites. Bright lights of condominiums, homes, and hotels are believed to entice hatchlings inland instead of toward the sea, resulting in thousands of turtle deaths on roads and in storm drains each year. Revetments to protect homes and hotels from stormy seas also wall off turtles from nesting sites.
It is not known if scientists' efforts to introduce turtles to safer beaches will be successful. Turtles nest on the beaches on which they were hatched. So the effort goes into the new generations - transplanting eggs to new beaches. Some of these turtles won't begin to nest for 15 to 30 years.
Turtles are also in need of cleaner oceans. Now they are beginning to choke and die on plastic bags (which can look like jellyfish), tar balls, and discarded monofilament lines.
Some biologists think sea turtles have survived some 150 million years because they live at sea, a more stable culture than land. But it may be the land culture that finishes them off. In the years ahead, man's choices on how he will develop beaches and use coastal waters and reefs will shape the turtles' future.