Under the Marine Mammal Protection Act of 1972 (as amended), an Unusual Mortality Event (UME) has been declared for bottlenose dolphins in the Mid-Atlantic region from early July 2013 through to the present day. A much higher number than usual of strandings of Bottlenose dolphins has occurred in New York, New Jersey, Delaware, Maryland and Virginia.
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© Marine Mammal Stranding Center
Bottlenose dolphin stranding in NJ
These Bottlenose dolphin strandings are more than seven times the historical average for the month of July for the Mid-Atlantic Region. All age classes of bottlenose dolphins are involved and strandings range from a few live animals to mostly dead animals with many very decomposed.

As yet, there are no unifying gross necropsy findings although several dolphins have presented with pulmonary lesions. Preliminary testing of tissues from one dolphin indicates possible morbillivirus infection, although it is too early to say whether or not morbillivirus may be causing this event.

Probably infectious disease

Based on the rapid increase in strandings over the last two weeks and the geographic extent of these mortalities, an infectious pathogen is at the top of the list of potential causes for this UME, but all potential causes of these mortalities will be evaluated. Work is underway to determine whether an infectious agent affecting these dolphins is present in collected tissue samples.

25 years since last major event when more than 740 dolphins died

It has been 25 years since the 1987-1988 bottlenose dolphin morbillivirus mortality event that occurred along the mid-Atlantic coast, involving more than 740 animals and spanning from New Jersey to Florida. That massive die-off, along with a humpback whale mortality event in 1987 off the coast of Massachusetts and the 1989 Exxon Valdez oil spill prompted Congress to formally establish the Marine Mammal Health and Stranding Response Program with the specific instructions for the UME Program as Title IV of the MMPA.

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