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Virus, polluted waters cited in major dolphin deaths

Hundreds of dead and dying dolphins are washing ashore in Spain, France and Italy. The mammals are victims of a virus that some scientists believe is linked to the heavy pollution of the western Mediterranean. The authorities in the three countries are reporting numerous strandings, and observers in aircraft and boats have spotted many other carcasses afloat.

The dolphins are also drifting ashore here along the rocks and beaches around Toulon, some dead, some still alive but dying.

"They look normal, beautiful, but they shiver like a person with a bad flu and they die quickly," said Jean-Michel Bompar, a doctor in Toulon.

Scientists who have just concluded laboratory tests said the animals had been infected with a virus similar to one in 1988 that killed some 18,000 seals in the North Sea, about one-fifth of the seal population in those waters.

They said the disease induces pneumonia and attacks the liver. Because there is no known cure for this strain of the morbilli virus, they expect many more dolphins to die.

The epidemic has worried and angered specialists who argue that this is one more loud warning signal coming from the deeply polluted waters around Europe.

Autopsies have revealed that so far all the dolphins tested were highly contaminated with chemical pollutants, including metals and highly toxic polychlorinated biphenyls, or PCBs.

While these substances have been linked to a drop in fertility in marine mammals, specialists said this week they feared they may also have weakened the dolphins' defenses against disease.

"We found extremely high levels of PCBs, ranging between 480 and 2,800 (parts per million)," said Alex Aguilar, a professor of biology at the University of Barcelona. The compound is considered dangerous for humans above 50 parts per million. But he said scientists were still searching for a link between the stress of pollution and the dolphin epidemic.

At universities in Milan and Genoa, Italy; Montpellier, France, and Valencia, Spain, environmentalists this week were also linking the disease to a general degradation of the Mediterranean ecosystem.

That degradation has already killed off once-rich fishing grounds, reduced the once-abundant Mediterranean monk seal colony to a few hundred survivors, spawned enormous pollutant-fed algae blooms around Italy and caused large fish kills.

Researchers at several institutions said they have no clear answers for the spread of the virus. But most agreed that uncommonly mild winters and decades of pollution coming from industries, ships and cities appeared to have created unusual conditions that favored the spread of disease.

The death of striped dolphins, the most common type in this region, was first noticed on the east coast of Spain, off Valencia, in early August and appeared in Barcelona by September, according to researchers interviewed along the Spanish coast. But the real shock came, researchers said, when Spanish, French and other specialists met at a conference in southern France on Oct. 15.

"Everyone reported a large number of strandings," said Bompar, who belongs to a university network in France that records beached marine mammals. "We realized there was a large epidemic that was expanding."

Along France's Mediterranean coast, where on average 50 dead dolphins appear per year, he said, more than 50 had been found just in the past two weeks. "There are so many we are losing track," he said.