In the darkness of a hot, tropical night, convicted thief Rolando Sandoval flashes his eyes out to sea, recalling the fear he first sensed when he heard he was being sent to Coiba.
"I knew I had done wrong. But this? I felt as if I was being sent to hell before I had died," said Mr. Sandoval, who was sentenced three years ago for his role in a lottery ticket scam.
Coiba Island is Panama's penal colony, a dense jungle in the Pacific Ocean, three hours from the mainland by boat, and ringed with sharks. It is a place of exile for murderers and rapists.
As the oppressive wind blows through Coiba's crumbling prison cells, prisoners whisper macabre stories of past cannibalism by inmates.
It is the world's largest island prison after Australia, which served as a penal colony during the late 18th and early 19th centuries.
Panama's former military dictator Manuel Noriega, inspired by French Guiana's notoriously brutal penal colony, Devil's Island, sent political prisoners to Coiba for torture during his rule in the 1980s.
It is not surprising that the graves of prisoners who died on Coiba are nameless.
But when Mr. Sandoval arrived on the island to serve his sentence, his initial reaction was one of disbelief, not fear. "I saw prisoners playing chess in the shade of the palm trees, chatting and drinking coffee, and the atmosphere was very pleasant," he said.
Things have indeed changed on Coiba. After the end of military rule in 1989 and pressure to clean up the island, plans are under way to tap its newfound status as a national park.
The nearly 500-square-kilometre island was made a national park by decree in 1991. But it was only in April that the Panamanian government passed legislation formally securing Coiba's status as a protected area and giving police two years to close the penal colony.
There are also plans to open the island to more tourism, on the model of Ecuador's Galapagos Islands.
"We would like around 30,000 visitors a year to enjoy the island's truly incredible ecosystems," said Lider Sucre, the director of the Panama City-based conservation group Ancon.
Coiba is the largest island in Central America, 85 per cent of it being virgin tropical forest. That makes it the biggest virgin-forested island in the Americas. About 80 per cent of the nearly 30,000-square-kilometre park is oceanic, filled with whales and rare tropical fish.
Coiba is perhaps best known among conservationists for a variety of rare wildlife, including bottle-nosed dolphins, the brown-and-white Coiba spinetail bird (the only bird of its kind in the world), and Panama's last cluster of scarlet macaws. Coiba also is home to 17 species of crocodile and 15 species of snake.
Although Coiba Island is still a high-security prison, only the penitentiary's menacing headquarters, a cellblock known as Central and two beachfront prison camps are operating.
Under General Noriega, the island, which was made a penal colony in 1919, played host to about 3,000 prisoners spread over 30 prison camps. Today, there are just 75 detainees.
"We have reduced the number of inmates since the 1990s," Coiba prison chief Frank Pinilla said. "The island's status as a national park is more important now."
The newest threat to Coiba is the increasing number of commercial fishing boats from Panama and neighbouring Costa Rica, which trawl for sharks along the island's coast.
"The sharks make excellent shark-fin soup for restaurants in the United States," said Clemente Nunez, the national park's director. "About 100 boats come to fish here every month, damaging the unique Pacific coral and depleting the shark community."
While the number of park rangers and coast patrols is increasing, the island faces further environmental degradation unless funding is increased, the Ancon conservation group says.
Coiba's national park is run on a $15,000 (U.S.) budget, a woefully small sum, Ancon says. "The penal colony scared people off from settling on Coiba, protecting the island's wildlife. But now as both locals and poachers know it is safer, we could see growing marine and bird-life degradation," Mr. Sucre said.