What started as a road trip for a San Diego State graduate student has turned into an international campaign to revive a population of sea turtles thought to be wiped out of the eastern Pacific Ocean.

A few months of research in Baja California proved that hawksbill turtles hadn’t disappeared. Instead, over the eons, a remnant group has traded the open ocean for the muddy mangrove estuaries of Central and South America.

The discovery provides a dramatic example of biological adaptation and offers hope for the turtles — if pivotal wetlands can be protected from development and poachers.

“We pinch ourselves all the time,” said Alexander Gaos, a doctoral student in a joint ecology program at SDSU and the University of California Davis. “Only three years ago people thought they were gone, and now look at us.”

Gaos, 34, runs the multinational Eastern Pacific Hawksbill Initiative and has co-written a chapter in a forthcoming book about sea turtles with his wife and fellow conservationist, Ingrid Yañez. He has gained the admiration of pioneering scientists such as Jeffrey Seminoff, an international authority on sea turtles at the National Marine Fisheries Service in La Jolla.

“In my 24 years working with turtles, I have to say that this hawksbill stuff is the most exciting journey of discovery,” Seminoff said. “It went from a situation where they were written off to one where … there is a viable opportunity to try and recover them.”

Hawkbill turtle habitat in Gulf of Fonseca, Honduras. — Michael Liles

Hawksbills are among the large turtles that ply the world’s oceans; they can migrate for thousands of miles. The prehistoric-looking creatures can grow to 200 pounds, and they are distinctive for beakish mouths that allow them to reach into coral reefs for food.

They’ve been killed for their striking shells, which are turned into combs, rings and other curios. Like other sea turtles, hawksbills and their eggs are a valuable food source for seaside villagers.

People from El Maculis, El Salvador, follow a tagged hawksbill turtle to the water. Conservationists say without community support, the hawksbills are likely to disappear. — Ingrid Yañez

The combined effect was such that Conservation International recently listed the eastern Pacific hawksbill as one of the world’s most endangered turtles despite the recent mangrove findings. They were largely deemed unrecoverable in the region — until Gaos and Yañez went looking for adventure.

In 2007, they left their jobs with a turtle conservation program in Costa Rica and set out in search of hawksbills. What struck them was how leatherbacks had become the face of turtle conservation campaigns even though hawksbills were just as bad off and maybe worse.

They scanned the scientific literature, which barely mentioned hawksbills in eastern Pacific even though are they faring well elsewhere. A report by Seminoff did say there were turtles in the Gulf of California.

Gaos cobbled together a few thousand dollars for a Ford F-150. Yañez — about six months pregnant — joined him for a tour that started in Cabo San Lucas and covered 1,500 miles.

Along the way, they stopped in fishing towns and asked about hawksbills. After their child was born, the couple returned to the spots in Baja where word-of-mouth suggested they would find the rare creatures. After a couple months of diving and netting, they recorded 10 juvenile hawksbills with photos, tissue samples and measurements.

“We were flabbergasted,” said Gaos, who had hoped to find just one hawksbill so he could tell colleagues and donors about it. “Ten blew our minds. Before that, we thought there was a good possibility we would end up writing a paper saying there were no hawksbills left. This early discovery really solidified our desire to form the Eastern Pacific Hawksbill Initiative and to become the centralized hub for hawksbill data in this part of the world.”

In 2008, Gaos presented his hawksbill findings at an international sea turtle symposium in Loreto, Mexico. He had more questions than answers: Why did he only find juveniles in the gulf? Where were the nesting spots? He still can’t answer the first question, but he has solved the second one.

An inexperienced researcher from El Salvador showed up at the same meeting and said he had come across 80 hawksbill nests. Seminoff and Gaos were still buzzing with excitement when they returned to San Diego. There, Seminoff received an email from a scientist in Ecuador asking for identification tags to use on hawksbills.

A skeptical Seminoff balked and asked for photos. He soon got those images, which confirmed the presence of hawksbills and helped cement the need for the nonprofit initiative.

“It wasn’t just a guy and his wife, but it became all these representatives saying they would provide information,” Gaos said.

The series of field reports prompted Gaos and Seminoff to visit Central America, where another surprise awaited them: The hawksbills were nesting in mangrove estuaries that resemble overgrown riverbanks more than the broad, sandy beaches where sea turtles nest worldwide. That helped explain why the creatures had evaded detection by scientists for so long.

Gaos, Yañez, Seminoff and several others published their findings in August in the Biology Letters journal. In evolutionary terms, they said, the mangrove nesting could be a recent adaptation and the turtles there could be a unique branch of hawksbills.

Gaos’ conservation projects include paying locals to protect the eggs instead of gathering them for food, a tactic that helps both animals and residents. “They know the turtles better than anyone,” he said. “If they are not on our team, we are not going to get a fraction of the eggs that are laid.”

Eggs brought to conservationists are incubated in protected areas.

Gaos also is trying to establish an eco-tourism industry in which visitors pay for the chance to work with the turtles in their native habitat, and improve land conservation safeguards. The overall initiative runs on about $100,000 this year, an impressive sum just four years after Gaos and Yañez started looking for answers.

“(Gaos) went from sort of a junior biologist to a monster fundraiser,” Seminoff said. “He’s an absolute rock star. … It’s as if these discoveries were just waiting to happen and they needed the right person to be ready for discovery by the greater scientific community.”

While the accolades grow, Gaos said he’ll continue working every conceivable angle to secure more protections through habitat reserves, government support and help from villagers. “What we need to do in the next five years is consolidate these projects so that they are going to be around for years to come,” he said.

Mike Lee: (619) 293-2034; mike.lee@uniontrib.com