The carcass of a North Atlantic right whale was found Monday afternoon floating about four miles off Fire Island inlet on Long Island, New York, the National Oceanic and Atmospheric Administration reported.

“The carcass is extremely decomposed, and we are not able to provide any details on the whale’s cause of death, age or sex at this time,” NOAA said in a news release issued late Monday evening.

It is the first observed right whale death in U.S. waters this year. Nearly 30 whales – NOAA considers that figure to be unusual – have been found dead in U.S. and Canadian waters since 2017.

North Atlantic right whales are endangered, with only about 400 remaining. About 95 surviving whales are breeding females. The leading causes of whale deaths appear to be entanglement in fishing gear and vessel strikes.

Officials from NOAA, the Atlantic Marine Conservation Society, and other agencies hope to examine the whale’s remains on Tuesday.