After they crawl to the water as hatchlings, earth’s sea turtles — loggerheads, greens, hawksbills, olive ridleys, Kemp’s ridleys, flatbacks, and leatherbacks — ply the seven seas, belonging to no nation. Males never touch land again. Loggerheads in the surf at Baja hatched under Japanese sand. Leatherbacks seen off California have traversed 6,000 miles of Pacific from nesting beaches in Indonesia. Some greens in Florida hatched in West Africa.

A Kemp’s ridley sea turtle nests in south Texas. U.S. NATIONAL PARK SERVICE

All seven species have traded ability to retreat into their shells for water speed. Forelegs that have evolved into flippers propel them faster than any human ever ran. The aptly named leatherback has even traded away its shell. Like dinosaurs, many of which were its contemporaries, it can heat its blood — “earth’s last warm-blooded monster reptile,” ecologist Carl Safina calls it in his book Voyage of the Turtle. It swims above the Arctic Circle and dives to at least 3,900 feet — deeper than sperm whales. The world’s heaviest reptile, it can weigh more than 1,900 pounds. The last natural land predator of adult female leatherbacks may have been Tyrannosaurus Rex.

Humanity has reduced sea turtles by something like 95 percent. Sources of mortality to which turtles evolved no defense include butchering for meat, egg taking, oil spills, drowning in nets, entanglement and hooking by longline fishing gear, lighting that draws hatchlings away from the star- and moon-lit sea, trash that mimics food and blocks digestive tracts, and two futile responses to sea-level rise brought on by global warming — beach renourishment with unsuitable sand and seawalls that block access.

“We’re losing nesting habitat,” says David Godfrey, director of the Gainesville, Florida-based Sea Turtle Conservancy, citing seawall permits and beach-renourishment funds his state hands out like Halloween candy. There’s a direct threat to sea turtles from global warming, too. Turtle sex is determined by egg temperature. Almost all loggerheads hatched in Florida are female, but in the cooler climates of South Carolina and Georgia about 40 percent are male. So warming in those states could extinguish most East Coast reproduction.

Adult female leatherbacks in the Pacific are down to an estimated 2,300 from 90,000 in 1980. In the North Pacific loggerheads declined about 80 percent from 2001 to 2011. The situation is no less desperate in the Indian Ocean.

Leatherback turtle nests on Florida beaches are up from 27 in 1989 to a record 641 in 2014.

But while there’s cause for despair, there’s also cause for hope. The main source of that hope is the U.S. Endangered Species Act (ESA) under which all sea turtles are protected. It has set a global example, inspiring action by some other nations, particularly in the Western Hemisphere. And in the U.S., the act has mandated mitigation measures for the main sources of sea-turtle mortality and established draconian penalties for harming sea turtles.

Though sea turtles are still grievously endangered, dramatic population increases in some waters demonstrate that recovery is possible everywhere. For example, a study published in the journal Global Ecology and Biogeography found that “six of the major green turtle nesting populations in the world have been increasing over the past two to three decades following protection from human hazards such as exploitation of eggs and turtles [suggesting] that the green turtle is not on the brink of global extinction.” Under new protections, hawksbill have reappeared off Honduras, El Salvador, and Nicaragua; and nesting is up substantially in places like Brazil, Barbados, and the West Indies. Leatherbacks are doing much better in Costa Rica and Panama. On Florida’s monitored beaches leatherback nests have increased from 27 in 1989 to a record 641 in 2014.

I feel the hope in places like the Archie Carr National Wildlife Refuge on Florida’s east coast where density of sea-turtle nests is greater than any beach in North America. On a foggy July night, Godfrey and I dive onto refuge sand when a dark form materializes in the wash. We can’t move for fear of spooking her. She’s a green turtle, well over 300 pounds. She kicks sand eight feet in the air, half burying me, then brushes me with a flipper after finishing her nest. When the Milky Way finally appears, we can make out turtles hitting the beach like landing craft. A loggerhead, toting an ecosystem of barnacles, moss, and shrimp-like creatures, hauls out and nests beside me. When she heads back I caress her carapace, my fingers leaving five trails of phosphorescence.

So intense is government and NGO outreach and so intimidating are ESA sanctions that it’s now almost unheard of for an American to harm sea turtles. Floridians, who host 90 percent of the nation’s nesters, adore them. Citizen groups patrol beaches, identifying species, reporting strandings, monitoring nesting. Notices to protect sea turtles and dim lights festoon public buildings. Virtually all the state’s green and loggerhead nesting sites are protected by county and municipal lighting ordinances.

In poorer nations, sea turtles and their eggs are still quick sources of food and money.

“Many more countries are enacting laws,” says Godfrey. “People are getting trained on how to protect and monitor. All along the Caribbean coast, in Mexico and into Central America it’s hard to find a significant nesting beach where there isn’t a local, national or international group that has people on the beaches.”

But in poorer nations sea turtles and their eggs are still quick sources of food and money, even when there are laws to protect them. Laws are meaningless without enforcement, and in most of the world there is little or none.

On a blistering June day in 1995, I squatted on the sand of Padre Island National Seashore in South Texas while the Park Service’s Donna Shaver dug up ten-minute-old Kemp’s ridley eggs the color and size of ping-pong balls. Taking pains to maintain their orientation, she placed them in a cooler full of sand from the nest site. Final count: 104. Two hours later they were in an incubator. This was a last-ditch effort to save a species that had declined from 40,000 nesters seen on a single day in 1947 at Rancho Nuevo on Mexico’s Gulf coast to about 700 annually four decades later. Extinction seemed imminent.

The nest we found that day 19 years ago was an early result of a decade-long, multi-agency project that transported 22,507 eggs from Rancho Nuevo to Padre Island where they were hatched in controlled conditions and released into former habitat.

Drowning in shrimp nets was — and still is — a major source of mortality for Kemp’s ridleys and other turtles. In 1980 the National Marine Fisheries Service (NMFS) unveiled, but did not mandate, its Turtle Excluder Device (TED) — a slanted metal grid that passed shrimp into the net but shot big stuff like trash and turtles out through a trap door.

Louisiana responded to the advent of TEDs by passing a law in 1987 prohibiting state agents from enforcing federal regulations to protect sea turtles. It’s still on the books. “Perhaps some species were just meant to disappear,” offered Louisiana’s then governor, Edwin Edwards. “If it comes to a question of whether it’s the shrimpers or the turtles, bye-bye turtles.”

On July 1, 1989 NMFS finally made TEDs mandatory, then suspended the regulation two weeks later after violent protests by shrimpers in which they blockaded harbors with their boats, rammed moored boats, fired guns, and threatened to blow up the tank in which young ridleys were being raised for later release. I met a TED manufacturer who’d had his car shot up. I saw stuffed turtles hung in effigy and real turtles, bashed and hacked. In 1994, after more delays and retreats, NMFS required shrimpers to deploy TEDs year-round; but not until 2003 did it require TEDs big enough to pass leatherbacks.

Longline fishing, in which baited hooks hang from miles of rope, are taking a devastating toll on turtles.

Some shrimpers sewed their TEDs shut, and enforcement was and is spotty. Still, Kemp’s ridley nests in Texas increased from six in 1996 to 209 in 2012. The species appeared to be on its way to recovery. But in 2013, Texas nests fell to 153 and in 2014 to 119. The BP oil spill and an increasingly popular method of shrimping called “skimming” are suspects.

Skimmer nets are pushed rather than dragged. And early on shrimpers who used them convinced NMFS that they should be excused from deploying TEDs because they emptied their nets before turtles drowned and didn’t catch many anyway. Both claims were swiftly proven false. When NMFS finally proposed TEDs for skimmers in 2012, the industry voiced shrill complaints, and the agency backed off.

It’s not just shrimp nets that kill sea turtles. Around the globe longlines, in which baited hooks hang from as much as 60 miles of rope, are taking a devastating toll. One study suggests that at least 200,000 loggerheads and 50,000 leatherbacks are caught annually. They don’t always drown; many are released with varying degrees of injury.

A study of six Costa Rican longlining vessels from 1999 to 2010 found that the most common catch after mahi-mahi was not a fish but the olive ridley turtle. Nine were caught per thousand hooks, indicating that the entire fleet caught almost 700,000 during the 11 years.

Longline fishing gear entangles sea turtles, such as this leatherback. PHILIP MILLIER

Shallow-set longlines for swordfish are especially lethal to loggerheads, which eat the bait, and leatherbacks, which get snagged by their enormous flippers.

But NMFS has gradually implemented regulations that, while not perfect, set the bar globally and are being adopted, at least to some extent, by other nations. U.S. shallow-set swordfish longliners operating in turtle habitat must now complete extensive training, carry turtle-hoisting and hook-cutting gear, bait with fish (which turtles pick at) rather than squid (which turtles swallow whole), and use large G-shaped “circle hooks” which reduce snagging and either can’t fit into a turtle’s mouth or usually impale it through the jaw rather than gut. Observers, required on many U.S. vessels, find that these measures can reduce leatherback snagging 83 percent and loggerhead hookings 90 percent while increasing swordfish catches 16 percent.

Canadian longliners targeting Atlantic swordfish haven’t implemented anything close to this kind of mitigation and, as a result, annually drown hundreds of loggerheads and leatherbacks. Yet the Marine Stewardship Council (MSC), the largest certifier of supposedly environmentally friendly seafood, granted the Canadian fishery its stamp of approval in 2012. This outraged the environmental community and undercut deserving MSC-certified operations such as the Canadian harpoon swordfish fishery, which has never killed a turtle, and Day Boat Seafood of Lake Park, Florida, which goes above and beyond U.S. regulations.

Day Boat’s co-founder, Scott Taylor, told me this: “We’re extremely upset by that certification. Canadians have no domestic market. All their swordfish comes to the U.S., so they trash our market. And here we are trying to meet this higher standard.”

While the fate of sea turtles remains much in doubt, there at last is reason for cautious optimism. The above-mentioned local recoveries will likely accelerate. If history repeats itself in the Gulf of Mexico, threats of lawsuits by NGOs will frighten NMFS more than histrionics from the industry, and the agency will require TEDs on skimmers. Trawl-towing shrimpers in the U.S. and other nations are learning that TEDs boost profits by increasing efficiency. The Canadians are clearly feeling the heat and may respond.

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And on December 1, 2014 NMFS announced that it will prohibit surface longlines in 26,858 square miles of the Gulf of Mexico from April through May and 5,679 square miles off North Carolina from December through April. The intent is to protect depleted bluefin tuna, but the closures will greatly benefit sea turtles.

When I feel despair I focus on an image I collected September 16, 2013 while fishing off Rhode Island — two mature leatherbacks within a mile of each other, each so close to my boat I could hear them breathe and count the spots on their ridged backs.

When you encounter a sea turtle in New England you’re supposed to call it in to the Sea Turtle Sighting Hotline. “Hey,” I told the receptionist, “I saw two leatherbacks on the same day. A record, right?”

“Well, no,” she said. A commercial fishermen had just called in 11.

