ALONG the rivers of the Amazon rain forest, people still recount legends in which pink dolphins are magical creatures that can turn into men and impregnate women.
Brazilian musicians write songs about them, singing lovingly about the "eye of the river dolphin".
But for Ronan Bencio Rego, a fisherman in this tiny settlement, pink dolphins are both his rival — and his prey.
Standing on the muddy banks of the great river, he said he had killed river dolphins many times before, to use as bait to catch a particular type of catfish that is sold to unsuspecting consumers in Brazil and Colombia.
"We want to make money," said Rego, 43, the president of the community, explaining that two dead dolphins could yield about $2,400 (1,450) in catfish sales in a single day of fishing.
But bait is not the only objective. Though the pink dolphins are protected by law, the fishermen see them as competitors for the catches that feed their families, and their frustration sometimes boils over. "I have harpooned some just to be mean," Rego said, lifting a harpoon to demonstrate how he would spear dolphins at close range.
The illegal slaughter of dolphins is rising, threatening one of the symbols of the Amazon and illustrating the challenge of policing environmental law in such a vast territory. Hundreds, if not thousands, of the estimated 30,000 river dolphins plying the Amazon region are dying every year.
Dr Miguel Miguis, 41, a Portuguese researcher who studies river dolphin populations, said the high rate of killings could lead to their extinction.
"They (the people] are killing their culture, their folklore," Miguis said. "They are killing the Amazon."
Upriver, in the biological reserve of Rio Trombetas, where river dolphins swim in an Amazon tributary teeming with piranhas and crocodiles, the dolphin population has fallen to a little over 50 earlier this year from about 250 in 2009.
"I am really worried about what is happening," Miguis added.
Brazil's environmental laws strictly prohibit the killing of dolphins and many other wild animals. Violators could face up to four years in prison. But enforcement in the vast Amazon is a huge challenge for Ibama, the Brazilian environmental protection agency, which has 1,300 agents covering the entire country. The Brazilian Amazon alone is larger than India.
Fishermen in Igarap said agents from Ibama had never visited their community of about 350 people.Luciano Evaristo, the director of environmental protection with Ibama, acknowledged a growing problem with the killing of river dolphins in the Amazon related to high demand in Colombia for the catfish, and he vowed to crack down on the practice.
Using dolphin meat as bait for the catfish "is horrible, and Ibama will stop this," Evaristo said. "When Ibama gets there, many people will be arrested."
Yet here in the heart of the Brazilian Amazon, many people are indifferent about the killings. At an open-air market in Santarm, street traders sell genitals removed from dead dolphins as good luck charms for sex and love. Jars of oil from river dolphin fat sit alongside oil from anacondas and crocodiles. The dolphin oil potion, which sells for about $25 a small bottle, is used to treat rheumatism, one female trader explained.
Legends aside, the slaughtering of Amazonian dolphins has become a serious concern for Brazilian officials. Ibama is planning to investigate the possibility that Brazilian fishermen were involved in an organised criminal operation linked to Colombia.
"The consumer has no idea what he is buying and consuming," said Fernando Trujillo the scientific director of the Omacha Foundation, an environmental group in Bogot. "And they have even less of an idea that dolphins are being killed to catch this fish."
Andrs Garca, 31, who runs a fish stall in the Paloquemao market in Bogot, said he would stop selling the catfish if he knew it was being caught with dolphin meat. "More than one of us would say no to this practice," Garca said. "The dolphin is an animal threatened with extinction. I wouldn't want to support something like that."
Miguis, the Portuguese biologist, has been on a crusade since 2005 to protect the river dolphins and identify their killers. He and some of his students identified several small settlements near Santarm where fishermen had turned to killing pink dolphins to attract the catfish. The fishermen sell them to local fish-processing plants, which export the catfish to Colombia and other countries.
Fishermen in Igarap claim they got the idea from Colombian fishermen. A few years ago, a group of Colombians near the triple frontier with Peru and Brazil taught at least two Brazilians a special technique in which they submerge a gloved hand into the water holding pieces of dead dolphin bones. The catfish, attracted by the dolphins' strong odour, quickly latched onto the bait, fishermen said.
The fishermen soon discovered that the catfish was a potential bonanza. "In just two hours we would be making more than $60," Rego said. "It was fast."
Rego and other fishermen claim they stopped slaughtering dolphins about a year ago, fearing action by the authorities, and now used pig meat to catch the catfish instead. But two fishermen's wives said many continued to kill dolphins, sometimes in front of their homes. "I saw many die here," said Silvia Rego de Santos, 31.In Igarap, veteran fishermen like Edilson Rocha, 58, recount stories of their battles with the pink dolphins.
To the fishermen, the dolphins are abundant in the river and should not receive special environmental protection. They say the dolphins cause a nuisance by getting caught in their nets as they try to feed on shoals of fish.
"We don't like him; we are his enemy," said Rocha, minutes after hoisting a stingray from the river with a hand-held fishing line. "I killed one when I was waiting for the fish to bite," he continued. "He kept coming closer and the fish were leaving, so I harpooned the dolphin. I couldn't stand it any more."