Dolphin Stranding Update: Tentative Cause of Unusual Mortality Event Determined
Published August 27, 2013
The National Oceanic and Atmospheric Administration (NOAA) has determined, though preliminary tissue sampling, that the cetacean morbillivirus is to blame for the unusually high number of Atlantic bottlenose dolphins stranding along the East Coast in recent months.
To date, 97 percent of the dolphins tested (32 of 33) are suspect or confirmed positive for mobillivirus. This is the same virus that caused over 740 marine mammals to strand in a similar event back in 1987-88, the last time a massive die-off of bottlenose dolphins along the Atlantic Coast like this was observed.
What is the morbillivirus?
Cetacean morbillivirus is a naturally occurring pathogen in marine mammal populations. It is not infectious to humans. At this time, there is no vaccine that can be easily deployed to stop the spread of the virus in wild, migratory dolphin populations; other than the animals natural ability to build antibodies to the virus.
Recently declared an Unusual Mortality Event (UME) by the federal government, these strandings have now reached numbers over nine times the historical average for the months of July and August for our region.
Although we have established a tentative cause, the UME investigation is still ongoing and stranding teams from New York to Virginia will continue to further evaluate tissue samplings and genetic sequencing. It may be years before we can truly confirm the cause for these strandings.
How is the National Aquarium involved in this event?
National Aquarium’s Animal Rescue team responded to a live stranded bottlenose dolphin last Tuesday, August 20 at Assateague Island National Seashore. After a health assessment of the animal, veterinary staff recommended humane euthanasia due to the poor health of the animal. A full necropsy (animal autopsy) was performed by Aquarium staff to determine an underlying cause of stranding. Tissue samples have been submitted as part of the UME, and results are pending.
I have also been assisting the UME Incident Management Team with drafting a weekly Incident Action Plan that outlines objectives for response in the affected areas, staff and equipment assignments, formulating safety plans, and addressing gaps in coverage that arise during response. The Incident Command Structure is very effective when coordinating response to events such as this that cover a broad area and involve multiple government and non-government organizations.
Our team will continue to work closely with regional stranding partners and the federal government to help implement this plan and document this event for future research/learning.
As we continue to closely monitor this situation, stay tuned to the blog for updates!