As evening falls over Sierra Leone's Banana Island archipelago, bats stream from their beachside roosts to circle in their thousands over the jungle village of Dublin.
Below them a struggle is playing out over an unexpected commodity — the lowly sea cucumber, a fleshy, sausage-shaped creature that scavenges for food on the seabed.
It is a struggle that is familiar to many in the West African country.
Sierra Leone's resources — diamonds, gold, fish and more recently iron ore — have been extracted and exported in great quantities throughout its history, yet the country remains one of the poorest in the world.
While the Banana Islanders have no use for sea cucumbers, in China they are prized for their medicinal properties and as a natural aphrodisiac.
Growing demand — currently estimated at around 10,000 tons per year — has depleted stocks around the world, leading traders to search ever further afield for new harvesting grounds.
Locals say when the first Chinese traders arrived in Sierra Leone four years ago to harvest the island's little known, red-spined variety of Stichopus sea cucumbers, they called themselves investors.
When prices skyrocketed, the islanders hoped the windfall would both make them wealthy and bring development to the village.
Moses Taylor, a former village chief known locally as Lord Moe, recalls the visitors' promises with bitterness.
"They said they would build water pumps in the street, they said they would build street lights," he said, sprawled in a flower bed smoking cheap cigarettes. "They said they would build community centers. But they did nothing for us."
"They just used us and dumped us like rubbish," said Abu Bakar Kanu, a cucumber diver smoking marijuana with friends down the street.
The locals say after it became clear the development promises were not likely to be met, they banned diving with the oxygen tanks and air-compressors that they themselves cannot afford, and called on all cucumber buyers to pay 200,000 Leones ($46) to the chief before they could operate.
Local cucumber dealer Reginald McCarthy said these rules have been ignored.
"Now they come from Kent with boats and oxygen," he said. "You can't stop them."
Chinese traders running their export businesses out of Tombo village on the mainland a few kilometers away did not want to talk to the press about the locals' complaints. But Mohamed Bangura, who works for one exporter who asked to be identified only as Cham Jr., denied they were breaking any laws.
Cham's father was one of the first to export sea cucumbers from the Banana Islands, and is also one of those accused by the islanders of reneging on their promises.
Bangura acknowledged that the villagers' expectations had not been met, but contended the region was still better off. He noted that his company had supplied a generator to Tombo village, for example.
"The islanders are the main beneficiaries of our trade," he said.
Without access to international markets and lacking the capital to start sea cucumber trading operations of their own, the locals say they feel powerless, however.
Sea cucumber diving is a lucrative option compared to the meager earnings offered by a fishing industry hard hit by illegal and unregulated foreign trawlers.
Abu Bakar, who is in his 20s, has been diving since the beginning of the cucumber windfall. Selling his catch to Chinese buyers enabled him to invest in land on the coast to the south of the capital, Freetown.
"We thank God the sea cucumber has pushed us forward," he said.
Diving must take place in the dark, when the slug-like echinoderms emerge from their daytime resting places.
"The sea cucumber knows only darkness," said Lord Moe.
Every night during the season — which depends on the tides and light from the moon — Matthew Ray pushes off with a team of divers in a rickety, brightly painted canoe from a beach beneath a towering cotton tree.
After a half-hour boat ride through water glowing yellow with bio-luminescent organisms he reaches the cucumber fields, where collectors, sporting wetsuits and waterproof flashlights, dive for hours on end.
The work is arduous and repetitive. Many of the men use marijuana and other drugs to ease their burden. On one recent trip a man intoxicated with the ethoxylated alcohol, Tomadol, capsized a boat, prompting panicked bailing to keep the team afloat.
This particular trip yielded just two sea cucumbers, which were hastily boiled and salted to be stored until Matthew has enough to sell to his Chinese buyers and Sierra Leonean middlemen.
The going price is 150,000 Leones ($35) for a 7-kg bucket. How much they are resold for is not clear but Selina Stead, professor of Marine Governance and Environmental Science at Newcastle University, said by the time they reach the wholesale markets of Guangzhou, dried sea cucumbers similar to the Sierra Leone variety can fetch as much as $133 a kg.
Sierra Leone's government says conditions are generally improving in the country, pointing to a set of impressive economic indicators. The economy grew by 15.2 percent in 2012 on the back of an iron-ore bonanza. Projections for 2014 are not far below that, at 14 percent, according to the World Bank.
China has been a big part of that boom, with trade predicted to hit $2 billion this year.
But many Sierra Leoneans say they still have yet to see the benefits in their daily lives.
The jobs created by the major mining companies have had little impact on Sierra Leone's unemployment crisis, and firms have faced criticism from civil society over importing too many foreign workers and contracting foreign companies to do jobs local companies could have done.
Life expectancy remains at just 48 years and the country ranks 177th out of 187 countries on the human development index.
The sandy streets of Dublin village, once trodden by slaves destined for the Atlantic trade, reinforce the point that very little of the sea cucumber wealth has remained on Banana Island.
Decaying clapboard houses, built in the distinctive style of the returning slaves who arrived in Sierra Leone from the late 18th century, lie scattered through the bush. The only street lights are rusting wrought-iron relics left behind by early Portuguese settlers.
Clean water is scarce and electricity is enjoyed only by the few who can afford to run costly diesel generators.
There are also concerns that the sea cucumber boomlet may already be busting.
Victor Sawyer, the official in charge of sea cucumber research at Sierra Leone's Environmental Protection Agency (EPA) in Freetown, said the government intends to regulate the sector but has yet to conduct basic research.
"We don't want to get into a situation where it is overexploited. But we don't know the growth rate; we don't know the stock. We don't know anything now," he said.
Abu Bakar, one of the few islanders to have enjoyed modest profits from the trade, agrees the supply appears to be dwindling.
"Now it is not easy to find them," he said. "We strain a lot."