QUITO, Ecuador — The Galapagos Islands, the natural laboratory that Charles Darwin used to develop his theory of evolution, are now the scene of a man-made struggle for survival of the fittest between fishermen and conservationists.

Fishermen on the Galapagos archipelago, angry about limits on their lobster catches, have ransacked the Charles Darwin Foundation's research stations and harassed tourists in recent months. They even took giant Galapagos tortoises hostage, kidnapping them from a breeding center.

The hundreds of fishermen halted their protests in mid-November after the government met their demands by loosening limits on lobster trapping, increasing the quota to 80 tons from 50 tons and extending the fishing season through the end of the year.

But the struggle didn't end there. Now, Environment Minister Rodolfo Rendon said Wednesday, the fishermen are demanding "absolute liberty to fish, to use highly destructive methods, such as long-line fishing, and absolute freedom to fish for shark fins," currently an illegal practice in Galapagos waters.

The Galapagos archipelago, 600 miles west of the Ecuadorean mainland, is Ecuador's main tourist attraction. Its species of plants and animals, found nowhere else in the world, have unique characteristics that were made famous by Darwin, the 19th century naturalist. The foundation bearing his name is a main promoter of conservation of the island chain's delicate and threatened ecosystem