Federal wildlife officials raised a formal alarm on Thursday over the deaths of scores of bottlenose dolphins in waters off the east coast, saying that a fast-spreading infection could be attacking dolphin populations from New York to Virginia.
At least 124 of the mammals have washed onto beaches since July, all of them dead or dying, a spokeswoman for the National Marine Fisheries Service said in a conference call with journalists. In July alone, 89 dolphins were beached, seven times the usual number.
The agency, which is responsible for monitoring and protecting marine mammals, declared the deaths to be an “unusual mortality event,” opening the way for federal help in finding the cause.
Experts said anyone who finds a stranded dolphin should not touch it, should keep pets away and should alert the authorities.
Tests on one dolphin carcass have uncovered possible signs of morbillivirus, an infection similar to canine distemper that ravaged East Coast dolphins over a 10-month span in 1987 and 1988. More than 700 dolphins were stranded from New Jersey to Florida during that outbreak, one of the worst on record.
But news reports state that other dolphins stranded this summer had pneumonia, and officials said that it could take weeks to pin down the precise cause, if one is found.
Unusual mortality events are declared when a marine mammal die-off is judged unexpected, large and in need of immediate attention. Investigators have failed to find a cause of death in roughly half the 60 mortality events declared since the first one in 1991.
This summer’s strandings represent only a tiny slice of the four discrete populations of dolphins in the area. By the agency’s best guess, nearly 20,000 of the animals live in separate southern and northern migratory groups near the coast, more than 81,000 live in deep waters off the continental shelf and a group of about 785 live in the Pamlico Sound off the coast of North Carolina.
Experts cannot say with certainty which populations have been hit by the deaths. There are undoubtedly more dead or sick animals at sea that have gone undetected, officials said.
The bulk of the deaths, at least 64, have occurred off the coast of Virginia. At least 18 strandings have been recorded in New York waters and 26 off New Jersey.
