OCEAN CITY — Three more dolphins were discovered on the beach in Ocean City late last week and ultimately perished, although early indications are at least one of them was not related to the ongoing “unusual mortality event” and the moribillivirus associated with the massive deaths.
Two bottlenose dolphins washed up on the beach in Ocean City last Friday and early sample testing appears to indicate the deceased mammals were victims of the rare morbillivirus responsible for a massive die-off of dolphins in the mid-Atlantic region through much of the summer and early fall. A third dolphin washed up on the beach last Friday was not a bottlenose dolphin, but instead was what is referred to as a common dolphin.
The third dolphin was alive on the beach as first-responders frantically tried to save it and keep it alive for transportation to the National Aquarium in Baltimore for potential treatment and rehabilitation, but it ultimately perished during the response. First-responders were on the scene trying to provide comfort to the dolphin while animal rescue personnel were in route.
“The Maryland Department of Natural Resources responded to two carcasses on the beach on Friday and both were bottlenose dolphins,” said National Aquarium Stranding Coordinator Jen Dittmar this week. “The third dolphin that stranded on the beach was a live common dolphin, but it eventually died during the response. We don’t typically see common dolphins this time of year, which made that stranding a little unusual.”
Since at least mid-July, NOAA Fisheries Stranding Network members, including the National Aquarium’s Marine Animal Rescue Program (MARP) and the Maryland Department of Natural Resources (DNR), have been responding to an alarming increase in bottlenose dolphin strandings and the trend has not abated. In fact, bottlenose dolphin strandings increased dramatically over the historic statistical average during July and August, and although there has been some leveling off, the strandings on the beach in Ocean City last Friday along with dozens of others along the beaches of Maryland’s mid-Atlantic neighbors are evidence the alarming trend continues.
Through the end of August, there had been nearly 300 cases of dead or dying dolphins recovered or rescued in the mid-Atlantic region, compared to the historic mean over the same time period of 26. In August, NOAA Fisheries officials declared the situation an “unusual mortality event” and began conducting research, and in many cases necropsies on the deceased marine animals.
After completing initial diagnostic tests on more than two dozen animals from all of the affected states including Maryland and consulting with disease experts, NOAA Fisheries has determined the likely cause of the unusual mortality event is a virus, more specifically a cetacean morbillivirus, which is characterized as similar to measles in humans or canine distemper in dogs.
Dittmar said the two deceased bottlenose dolphins recovered from the beach in Ocean City last Friday were consistent with those diagnosed with the morbillivirus, but the third, the common dolphin, was not, at least early on.
“The common dolphin did not show consistency with the morbillivirus,” she said. “More samples will be treated, but we don’t suspect it to be related to the other cases.”
Dittmar said the number of bottlenose dolphin strandings has waned somewhat in recent weeks, but the lower numbers are not necessarily indicative of a reversal of the summer-long trend. She said the apparent decline could be the result of limited access to areas where deceased or dying dolphins are washing up in yet another example of the long reach of the ongoing federal government shutdown.
“We’re starting to see lower numbers of bottlenose dolphin strandings, but part of that is not having access to Assateague and other areas closed because of the shutdown,” she said. “The same thing is true in Virginia and North Carolina where there are a lot of federal lands not accessible because of the shutdown. We anticipate when the government opens back up we’re going to see a lot of unreported incidents.”
Dittmar said this week it was uncertain if the rough seas and high winds associated with the Nor’easter that lingered off the coast for several days last week and into the weekend contributed to the three strandings in Ocean City on Friday.
“The Nor’easter last week may have contributed to what we saw last week,” she said. “We don’t believe it was the primary reason, especially in the case of the two bottlenose carcasses, but it might have contributed to it.”