GALAPAGOS ISLANDS, Ecuador -- On these wild islands where giant tortoises lumber up erupting volcanoes, a battle over a wormlike delicacy is threatening to close the window on evolution that Charles Darwin opened more than a century ago.
Fishermen fleeing poverty have inundated this living laboratory and harvested millions of sea cucumbers, prized in Asia as a food and aphrodisiac. But in their quest to make a living, they have clashed with scientists and nature, taking hostages, killing the endangered giant tortoises for which the islands are famed and threatening death to ecologists who would scuttle their livelihood.
Scientists warn that the migration has reached critical mass and that, if the influx is not slowed soon, Darwin's legacy will be lost forever.
"This is a historic moment for the Galapagos," said Felipe Cruz, who retired as director of Ecuador's National Park Service last year over the government's paralysis in halting the fishing. "The sea cucumber problem is a symptom of a disease. And the disease is increased human presence on the islands."
Although tens of thousands of binoculars-wielding eco-tourists annually descend on the Galapagos, 15 years of tourism have not done one-tenth the damage the fishing boom has, scientists say.
For each of the past five years, the population of the islands has jumped 8 percent. Since 1992, when Asian demand exploded for the bottom-dwelling sea cucumber, hundreds of fishermen have sailed clandestinely into the archipelago, leaving social and environmental devastation behind.
In the past 15 months, nearly 100 endangered tortoises -- believed to have one of the longest life spans of any creature on Earth -- have been killed for their meat by fishermen camping illegally on the archipelago 600 miles off Ecuador. Coves and beaches untouched by humans for centuries are littered with human waste and trash. A 1994 fire started by fishermen raged through more than 20,000 acres of Isabela Island and threatened tortoise nesting sites before it was brought under control.
In January, the clash turned violent. Ecuador's army intervened to free scientists and their families held hostage for three days by fishermen enraged over plans to close a lucrative sea cucumber fishery.
Since then, ecologists have received death threats, and dozens of fishermen are defying a moratoriumimposed while government authorities study the impact of the fishing. The fishermen are selling their catch in mid-ocean to Ecuadorean dealers.
Having repeatedly extended the two-month ban, Ecuadorean officials appear ready to admit that they are powerless to enforce any prohibition or limits on how many creatures are pulled from the sea.
The government opened the fishery in October 1994 as an experiment, limiting the annual catch to 550,000 sea cucumbers. Two months later, after about 7 million had been harvested, the government banned further cucumber fishing, triggering the standoff with angry fishermen, known as pepineros.
For decades, scientists and a tiny population of lobster and grouper fishermen had lived harmoniously.
Today, the sounds of home building fill Puerto Ayora, the biggest town on the archipelago's 16 main islands. With fishermen drying the ill-gotten sea cucumbers on their roofs, the two groups rarely talk to each other anymore.
For the poor new immigrants who have swelled the population of the islands from 4,000 in 1982 to more than 12,000 today, the financial stakes are high. Ecuador is among the poorest countries in South America, and before the sea cucumber boom, fishermen in Ecuador's waters rarely made more than the minimum monthly wage -- $71.
By hauling up sea cucumbers, and then processing the spineless, wart-covered creatures for export to Asia, fishermen say they can make an average of $100 a day.
With industry and farming banned on the islands and tourism limited, fishermen say they have no option but to exploit the waters for profit. International treaties limit island agriculture to acreage controlled by the Ecuadorean government.
"The only way out is the sea, and what it holds," said Adolfo Aurelio Flores, 44, head of the fishermen's cooperative on the island of Isabela. He spoke outside the new, two-story concrete-block house he is building with money earned from sea cucumber fishing.
Isabela, where many of the recently arrived fishermen live, is eight hours by boat from the main town of Puerto Ayora, where authorities are based without a single patrol boat. Showing off his sea cucumber catch and taking a journalist aboard his boat with no fear of reprisal, Flores said he plans to continue harvesting until he pays off his house.
"I think that the conservationists have to take into account that if they don't allow the development of any other industry, there is no way for us to survive. How are we going to feed our kids? Do we have to turn to delinquency, to stealing? We need to live."
Conservationists agree that the fishermen's options are limited. Some want them to leave. Most favor a moratorium on sea cucumber fishing while scientists determine an annual catch that will not wipe out the species. Environmentalists say only strict enforcement will make such limits stick.
Ecuador plans to announce a solution later this spring, but it's not likely to please environmentalists. One high-level official said the government is leaning toward granting the fishermen the right to continue harvesting the sea cucumbers.
"Ecuador simply doesn't have the resources, although we want to protect the islands, to enforce a fishing ban in thousands of miles of open ocean," said Oscar Aguirre, subdirector of fisheries for Ecuador.
"We're seeing a mountain of people immigrate here who, if they don't have alternatives, will keep exploiting the resources. The problems are not easy to solve."
Ecuador has never appealed for help from international organizations to protect the islands. And while dozens of environmental organizations and hundreds of scientists worldwide have been sounding the alarm over computer networks, they say there is little they can do.
When describing the importance of this equatorial Eden to the study of evolution, scientists reach for religious comparisons.
"The Galapagos is to marine biologists what Jerusalem is to the Jews, what Mecca is to Muslims," said Elliott Norse, chief scientist with the Washington-based Center for Marine Conservation. "It is a rare window on evolution -- a place to look at the world evolving without the heavy hand of man. Once you upset the supremacy of nature there, the world loses that unique window forever."
Formed, like Hawaii, as the tips of volcanoes pushed above the sea's surface, the islands are among the few places in the world isolated and unadulterated enough to study Darwin's famous theory that plants and animals evolve by naturally selecting the strong and weeding out the weak. The Galapagos, never attached to a mainland, are the best of them, researchers say.
The influence of humans is so recent that the indigenous species -- a fantastic variety of albatrosses, bluefooted boobies, lava lizards, swimming marine iguanas and other living things seen nowhere else in the world -- have no fear of people.
Darwin journeyed to the islands aboard the research ship Beagle in 1835, and his observations became the basis for his paradigm-shaking work, "The Origin of Species."
Today scientists are doing what Darwin thought impossible. They are studying the evolutionary process not through fossils but in real time, in the wild: evolution in the flesh. Scientists say the research is important because the survival of the species may depend on understanding how Homo sapiens came to be and adapted to a changing world.
"We're talking about one of the few truly wild places left on earth," said Craig MacFarland, president of the Charles Darwin Foundation for the Galapagos Islands, based in Virginia. "What's at stake here is Darwin's legacy and the question of how to preserve it and allow very controlled use by man."