OCEAN CITY — A significant spike in the number of dead and decomposing bottlenose dolphins turning up in the waters along the mid-Atlantic coast this summer, including seven in Maryland during the month of July alone, have scientists “alarmed” as they continue to seek answers for the sudden phenomenon.

The seven deceased bottlenose dolphins found in Maryland continues a somber summer-long trend throughout the mid-Atlantic region from North Carolina to New York. Of the seven recovered in Maryland waters in July, most were found in and around the Chesapeake Bay, although some have been recovered along the Atlantic coast at Ocean City and Assateague.

For example, two weeks ago the Ocean City Beach Patrol recovered a dead dolphin close to shore in the resort after tracking the whereabouts of the marine mammal throughout the day. Lifeguards brought the deceased marine mammal ashore where it was handed over to the Maryland Department of Natural Resources (DNR). Scientists are now performing a necropsy, the marine equivalent of an autopsy, on the deceased dolphin although no results have been reported.

The recovery of the dead dolphin continues a strange summer-long trend throughout the mid-Atlantic region, a trend for which there is no immediate answer. Just to the south, the Virginia Aquarium and Marine Science Center has also responded to a higher number of dead and dying bottlenose dolphins this summer, mostly concentrated in and around the mouth of the Chesapeake Bay.

The Virginia Aquarium’s stranding response team has responded to 82 dead or dying bottlenose dolphins thus far this year including 44 during July alone. The average number of dolphin stranding responses for the Virginia agency during July is seven. Closer to home, DNR will, in an average year, recover one dead or dying dolphin during a typical July, but the agency picked up seven in Maryland waters during the month.

In Maryland, the DNR responds to deceased marine mammal recoveries, while the National Aquarium’s Marine Animal Rescue Program (MARP) responds to rescue and rehabilitate live marine mammals stranded along the state’s coasts. Thus far, the MARP team has not responded to any live dolphin strandings in Maryland this year, according to National Aquarium Stranding Coordinator Jen Ditmar.

“We haven’t had a live bottlenose dolphin stranding in Maryland in 2013,” she said this week. “We are seeing a high number of dead dolphin recoveries, which is alarming. A lot of them are pretty decomposed, so it’s tough to get good samples. It’s hard to tell at this point what is causing them to die and there could be a lot of reasons. Nobody is ready yet to start pointing fingers at one possible cause.”

According to a Virginia Aquarium and Marine Science Center release, necropsies have been performed on many of the deceased dolphins, but the results thus far are inconclusive.

“Many of the animals are just too decomposed to offer much information, but samples from fresher animals have been collected and will be analyzed,” the release reads. “Unfortunately, it can take some time for results, and even then, they may be inconclusive.”

Virginia Aquarium and Marine Science Center Research Coordinator Susan Barco said the sudden spike of deceased dolphins off the mid-Atlantic coast appears on the surface to be caused by an unidentified disease.

“This is really frightening because these animals are sentinels of ocean health,” she said. “Strandings have been much more common and we think it’s an indication of the health of our ecosystem.”