VIRGINIA BEACH, VIRGINIA — A decomposed body of what may be a North Atlantic right whale had likely been afloat for a while along the Atlantic Coast before it was found May 31 by state bird surveyors on Metompkin Island, according to a researcher with the Virginia Aquarium.

“It’s very hard to tell when and where it did die,” said Susan Barco, a research coordinator at the aquarium who works with its marine stranding response team.

Scientists at the aquarium will use samples taken by bird surveyors with the Virginia Department of Game and Inland Fisheries who happened upon the carcass to try to confirm that it is a right whale, Barco said.

“We’re pretty sure,” she said, describing the carcass, based on the documentation from the state officials, as a swath of blubber with a few bones.

The death of right whales is of particular concern to conservationists after last year’s 17 documented deaths and five live entanglements in the Gulf of St. Lawrence in Canada and off the Cape and Islands. Scientists have determined that several years of population growth turned to a decline around 2010. There are about 450 of the animals left worldwide.

Right whales are protected under federal laws in both the U.S. and Canada but threats to the animals from ship strikes and entanglement in fishing gear have persisted. The U.S. declared an unusual mortality event last year for right whales, which allows the release of more money for analysis.

The first documented dead right whale in U.S. or Canadian waters this year was found floating Jan. 22 about 100 miles east of Virginia, and identified as a juvenile female known as 3893 in a right whale catalog. At the age of 3, the right whale had already survived an entanglement in gillnet float line after rescuers cut away some of the rope and she shed the rest. But six years later, in January, it appeared another entanglement in fishing gear was the cause of its death.

“Certainly the early one most likely made its way near our area before it died,” Barco said about the carcass found Jan. 22.

There are currently only about 100 females of breeding age in the North Atlantic right whale population and more females seem to be dying than males, according to information released by National Oceanic and Atmospheric Administration Fisheries. The birthing rate has also been declining in recent years, and no new calves were spotted in the calving grounds off Florida this year, the agency said.

Investigations are continuing into the deaths.

— Follow Mary Ann Bragg on Twitter: @maryannbraggCCT.