NANTUCKET, Mass. — The National Oceanic and Atmospheric Administration says the third death of a rare North Atlantic right whale this year has been confirmed.

NOAA and conservationists are keeping a close eye on the right whale population because of high mortality and low reproduction in recent years. The agency says a right whale carcass was found floating about 100 miles east of Nantucket on Sunday.

NOAA says photographs of the animal show wounds consistent with entanglement. Entanglement in fishing gear is a significant cause of death for right whales. The agency, however, says it’s still too early to speculate on the cause of death.

Right whales number no more than 450. About 4 percent of the animal’s population died in 2017. No new calves were spotted this year.