From New York to Virginia, dead dolphins have been washing ashore in unusually large numbers this summer. As of Aug. 20, nearly 300 stranded bottlenose dolphins had been reported in the region, according to the National Oceanic and Atmospheric Administration, nearly seven times more than normal in some places.
As experts continue to investigate the cause, the leading contender is an infection called morbillivirus. Related to human measles and canine distemper, the virus seems to cause sporadic epidemics among dolphins. Many years, there are no detected cases, but when the virus hits, it can hit hard. The last epidemic struck off the Atlantic coast in the winter of 1987-88, killing more than 740 animals from New Jersey to Florida.
For now, there is no official announcement to confirm that morbillivirus is the culprit in the current outbreak, though experts involved in the investigation say that the virus has been confirmed in at least some of this year’s stranded dolphins.
“It’s no secret at this point,” said Perry Habecker, a large animal pathologist at the University of Pennsylvania’s School of Veterinary Medicine in New Bolton. His team has been analyzing tissues from dolphins that are washing up in New Jersey. “Morbillivirus is accounting for some of these deaths.”
Every year, at least some dead dolphins wash up onto beaches. Some get hit by boat propellers. Others get caught in fishing nets. Still others succumb to viruses, bacteria, lungworms, fungal infections and other diseases.
From 2007 to 2012, according to NOAA data, between 88 and 113 dolphins washed ashore in the area of the current East Coast die-off. As of last week, the current tally is 299, with a large spike since early July.
In New Jersey, there are usually between half a dozen and dozen strandings each year, said Bob Schoelkopf, founding director of the Marine Mammal Stranding Center in Brigantine, N.J. So far this year, there have been 74 dead dolphins found on the state’s beaches. In Virginia, there were 45 strandings last month, compared to the state’s annual average of just seven in July.