Last week, the National Oceanographic and Atmospheric Administration (NOAA) declared an unusual mortality event in the Mid-Atlantic. For the month of July, dolphin mortalities were higher than average for the states of New York, New Jersey, Maryland, and Virginia. Stranding responders in these areas are working very hard to keep up with the number of dolphins washing ashore, and have been working to perform necropsies (animal autopsies) on as many dolphins as possible. During a necropsy, biologists look for signs of external or internal injuries, signs of disease or illness, and take routine tissue samples for laboratory analysis. Virginia has already collected over 100 bottlenose dolphin carcasses this year, which is about 20% more than their average for a whole year.
NOAA is compiling data that is being provided by the stranding networks and comparing it to historical numbers. This information will help NOAA determine if there is a widespread trend or if there are common factors across the affected areas. The last time a well-documented die-off took place was in 1987 when more than 740 bottlenose dolphins died in a range from New York to Florida. It took several years to compile test results and determine that the culprit was a measles-like virus known as morbillivirus. While it is unknown what is causing the present day die-off, biologists are not ruling out biotoxins, bacteria or viruses as a possibility. Charley Potter, a marine mammal biologist with the Smithsonian Institute is assisting the Virginia Aquarium with investigating the dolphin deaths, and is concerned that this event could be similar to the 1987 event, but it is still too early to tell.
Stranding networks play an important role in supporting the NOAA Fisheries Service through an array of unique research and monitoring opportunities to fulfill NOAA’s core mission. The national stranding network is a successful public/private venture for monitoring marine mammal strandings. Marine mammals are important indicator species of the ocean health, so monitoring their health through strandings is important for understanding the health of our oceans and the impacts of human activities in a time of significant development and change. The stranding networks and NOAA will continue to work together to investigate incidents such as this, and more information will be released as it becomes available.
What can you do to help during this event?
- Report any live marine mammal strandings or mortalities to the local stranding response facility. In Maryland, call the Natural Resources Police at 1-800-628-9944.
- If you do find a stranded dolphin, wait for directions from the local stranding responder – do not touch the animal or try to return it to the water. Doing so could cause more harm.
- Make a donation to a local stranding response organization. Events like this require a lot of basic equipment, supplies, and fees for processing tissue samples.