Gulf right whale (copy)

The imperiled right whale females apparently produced no calves during their winter migration this year. Specialists fear the species is about to go extinct. Neal Hart/Provided

No new calves of the imperiled right whales were born this year, according to surveyors — furthering fears that the species is on what one expert called the "knife edge" of extinction.

The absence of newborns is something that hasn't been seen in 30 years of observing the whales' migration. The National Marine Fisheries Service made the announcement as survey flights shut down at the close of the winter calving season.

The news comes with the whale population in an extremely vulnerable position, said Michael Jasny, the marine animal protection director of the National Resources Defense Council. He characterized it as a knife edge.

"It could be the beginning of the end," said Barb Zoodsma, who oversees the service's right whale recovery program in the Southeast.

Right whales are the rarest of the large whales, with fewer than 500 known to be alive, including only about 100 mature females.

They are massive 40-ton creatures. Their two-plume breathing spray and the lack of a dorsal fin distinguish them from other whales.

They migrate south to calve each winter, so close to the East Coast that a mother and calf pair was spotted in 2005 in the breakers off Pawleys Island near Georgetown. The proximity to boating, fishing and shipping has become deadly.

Last year, 17 washed up dead in the U.S. and Canada.

The apparent absence of right whale calves follows the 2016-17 winter during which only three female and calf pairs were spotted — in contrast to 39 pairs in the peak year of 2009. Numbers declined for four years to before the zero report this year.

The Associated Press contributed to this report.

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