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[NicoleRussell]

By James C. McKinley Jr. The New York Times


SUNDAY, FEBRUARY 19, 2006



MEXICO CITY The Mexican authorities are investigating the mysterious deaths of eight whales found washed ashore along the Sea of Cortez last month, an unusually large number that suggests some common cause.
The whales come from several plankton-eating species and apparently died at sea in November and December, biologists said. But they do not show any signs of having been caught in long-line fishing nets, which sometimes suffocate the mammoth animals. Nor have biologists found any signs of a toxic spill or outbreak of disease that would account for their deaths.
"Right now, it's a mystery," said Luis Fueyo, an assistant federal prosecutor for environmental crimes, who is overseeing the investigation. "We have a puzzle."
The first sign something was wrong came on Jan. 4, when the remains of two humpback whales were spotted on the shore near the town of El Dorado in Culiacán state.
Scientists determined they had died in early November. Since then, six more giant bodies have turned up, among them a third humpback, a minke whale, a fin whale and a baby gray whale. Three bodies were discovered on Jan. 18 during an aerial search of the Sinaloa coast.
The discovery of the carcasses set in motion a frantic search for forensic evidence. Biologists tracked currents to determine if all the whales might have been in the same place when they died, even though they ended up scattered over a 800-kilometer, or 500-mile, coastline.
The investigators also looked for signs of disease or poisons, both natural and synthetic. It was slow going. All of the bodies were badly decomposed. Only the baby gray whale provided enough tissue to test for diseases or poisons.
On Friday, environmental officials announced that those tests had found no evidence of a toxic algae bloom, other poisons or infections.
Nor have the investigations turned up signs of mistreatment by fishermen.
The deaths occurred just as about 2,000 gray whales from the Pacific began arriving in the Sea of Cortez, where they spend every winter as part of a centuries-old migration pattern. Mexican officials say they usually find about 10 dead whales a year; nine in the space of two weeks have set off alarm bells.
Environmentalists say the Sea of Cortez, one of the world's richest fisheries and most diverse marine habitats, is poorly policed and substantially overfished, because the Mexican government has granted more and more permits for trawlers to use long-line nets.
The deaths of so many whales has prompted urgent calls from some environmental groups for quick action to find the cause.
Besides the whales, two dolphins and an olive ridley sea turtle have also washed up dead in the same region.
"I'm worried," said Homero Aridjis, a poet and naturalist who heads the Group of One Hundred, an environmental organization. "We are just starting the year and already we seem to see a dead whale every day. Something is happening there and it needs to be investigated."
Fueyo, however, said none of the bodies showed signs of wounds from nets on their fins, nor signs of other trauma that might have been caused by fishing boats.
Biologists also did not find the usual telltale massacres of fish and sea birds that would accompany a toxic bloom of algae or another release of poisonous materials.
"What's happening is totally irregular," Fueyo said.