WASHINGTON (AP) – Government scientists believe they have some good news about the endangered right whale, whose population in the Atlantic Ocean is struggling to come back.

Scientists at the National Oceanic and Atmospheric Administration said Wednesday they have found evidence of a significant right whale population in waters off the southern tip of Greenland. The whale was thought to have largely disappeared from that area decades ago.

Only two of the whales have been sighted in the area in the last 50 years.

But now scientists, over a yearlong period, recorded 2,000 whale calls from underwater listening devices in the area. No whales were sighted.

There are 300 to 400 North Atlantic right whales off the U.S. Atlantic coast. It’s not known if the newly discovered whales in an area known as the Cape Farewell Ground, 200 to 400 miles off Greenland, are a separate population of right whales or ones that migrated from U.S. waters.

The discovery raises the possibility that the eastern North Atlantic right whale population, believed by many to be extinct, may still exist, said David Mellinger, a chief scientist at NOAA who presented the teams findings Wednesday at an Acoustical Society of America meeting in Portland, Ore.

Mellinger in a telephone interview with several reporters said no whales were sighted during the yearlong monitoring effort, but that by triangulating the five underwater listening devices it is certain at least three whales could be heard. “It gives us greater confidence that there are a significant number of right whales in the area,” he said.

The North Atlantic right whale is protected under the U.S. Endangered Species Act as well as international treaty. Over the centuries its population was devastated by whaling, especially in the eastern North Atlantic between Greenland and Iceland. Off the United States, fewer than 400 right whales are known to migrate annually between their southern Atlantic breeding grounds to feeding areas off New England.

Hunting the right whale, which can grow to 55 feet long and weigh more than 70 tons, has been illegal since 1936, but too often it has been the victim of ship traffic as it moves through heavily traveled Atlantic coastal waters on its migrations north. Last year NOAA directed new speed limits for commercial ships along the Atlantic coast to better avoid collisions with the whale.

The underwater recordings of right whale sounds off Greenland were made from July to December of 2007, although the recording devices were not removed until July of last year. But it would be months later before the scientists knew what they had discovered. Mellinger said the recordings contained tens of thousands of various whale calls, and it took sophisticated acoustical detection software to separate the right’s call from those of other whales.

The humpback whale makes a very similar sound, said Mellinger and “we took a lot of our time distinguishing humpback sounds from right whale sounds.”

“We were thrilled to hear these calls on the recordings,” he said. “But we knew it was a historic habitat area and an unstudied one. Now the question is how many whales are there, and what population do they belong to.”