Are the Mid-Atlantic Dolphin Strandings the Result of a Contagious Virus?

Written by on August 19, 2013 in Marine Life, Whales & Dolphins

UPDATE Nov 8 — Dolphins are heading south for the winter, leading to a significant drop in dolphin deaths in New Jersey. NOAA, however, warns that the number of deaths will increase in southern states, as the disease is expected to travel with the migrating animals. The cause of this Unusual Mortality Event is a measles-like virus called morbillivirus. Learn more here.

UPDATE Sept 9 — As part of the Cooperative Enforcement Program, NOAA’s Office of Law Enforcement was able to allocate funds to state partners to increase patrols in certain areas along the east coast. By increasing patrols, responders will be able to respond to new strandings much faster and will be able to collect fresh samples which will aid the ongoing investigation.

UPDATE Sept 5 — Marine mammal rescue centers that have been dealing with UMEs on both coasts recently learned that they won’t be receiving federal financial help next year. In the past, $4 million has been available to members of the marine mammal stranding network but this year, NOAA was forced to but its $5.1 billion budget by seven percent, resulting in cuts to marine mammal rescue programs.

UPDATE Aug 29 — The Christie Administration recently directed additional state resources towards the investigation of bottlenose dolphin deaths in the Mid-Atlantic. The Administration is now providing the use of a Department of Agriculture lab for testing which will greatly benefit the Marine Mammal Stranding Center. Learn more here.

UPDATE Aug 26 — In a new statement, NOAA writes “To date, 32 dolphins tested from all five states are either suspect or confirmed positive for morbillivirus.” The good news is that scientists are now pretty sure what the cause is, but the bad news is that if it really is a virus, there’s no way to stop it from spreading.

UPDATE Aug 23 — Oceanus Magazine posted a video today about how scientists study marine mammals with technology designed for humans. This video is particularly interesting now because of the UME in the mid-Atlantic. Researchers discuss the necropsy process and how they are able to determine the overall health of the animal and the cause of death. Take a look: Marine Mammals Meet Modern Medicine.

An Unusual Mortality Event (UME) has been declared for bottlenose dolphins in the mid-Atlantic region. The event began in July as dolphin strandings increased in New York, New Jersey, Delaware, Maryland and Virginia.

Bottlenose dolphins.

Bottlenose dolphins. Photo credit: NOAA.

Bottlenose dolphin strandings in July were more than seven times higher than the historical average and the numbers continue to rise through August. As of August 12, there were already more than 35 strandings in New York alone (compared to only 6 in August last year). The majority of the dolphins were already dead when found. The few that were found stranded alive died soon after.

The strandings have involved dolphins of all ages. Necropsy findings have not revealed a definite cause of death yet but due to the number and location of strandings, an infectious pathogen is at the top of the list of possible causes.

Tissue samples from at least one dolphin indicate a possible morbillivirus infection but it is too early to say if that is the cause of this event, but it has happened before. The 1987-1988 morbillivirus mortality event spanned from Florida to New Jersey and involved over 740 animals.

Morbillivirus in cetaceans is similar to distemper in dogs which causes breathing problems, brain swelling and other symptoms and often ends in death. Check out this post to learn more about the possibility of the UME being caused by this contagious virus.

To learn more, take a look at the FAQs for the current UME and listen to the following clip from NPR.

Or read this post from CNN: Dolphins dying by the dozens along East Coast.

Copyright © 2013 by Marine Science Today, a publication of Marine Science Today LLC.

About the Author

About the Author: Emily Tripp is the Publisher and Editor of She holds marine science and biology degrees from the University of Miami's Rosenstiel School of Marine and Atmospheric Science and a Master of Advanced Studies degree in Marine Biodiversity and Conservation from Scripps Institution of Oceanography. When she's not writing about marine science, she's probably running around outside or playing with her dog. .


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