New estimate lowers number of right whales

By Mary Ann Bragg 
Posted Nov 7, 2018 

Annual report card comes as researchers work to identify whale found dead off Nantucket. .

NEW BEDFORD — A gut feeling among North Atlantic right whale experts that the population of the beleaguered animals has dropped to around 400 has been reinforced with a new statistical estimate of 411 animals as of the end of 2017.

“The public shouldn’t think there are exactly 411 whales,” Center for Coastal Studies right whale researcher Charles “Stormy” Mayo said Thursday at the end of the two-day North Atlantic Right Whale Consortium annual meeting. “We believe that they are in the low 400s, or around 400.”

The consortium’s annual report card for the end of 2016 had set the population number at 451, using a statistical model unveiled last year.

The loss of about 40 right whales, under the statistical model, between the end of 2016 and the end of 2017 would include the 12 documented deaths in the Gulf of St. Lawrence in Canada and the five off the Cape and Islands linked in large part to human causes of entanglement in fishing rope and being struck by ships.

“Everyone in the field — conservationists, the public, scientists — continue to be saddened by the decline,” Mayo said. “There’s no question there’s a decline. There’s no question we need to solve the mortality issue.”

The maximum number of human-caused deaths should be no more than one a year to sustain the critically endangered population along the U.S. and Canadian coast, according to a federal stock assessment in September.

U.S. and Canadian government agencies and nonprofit organizations are working to identify the best ways to respond, with new technology to eliminate vertical ropes in the water, for example.

So far this year three right whale deaths have been documented, all in U.S. waters, and all linked to entanglement in fishing rope.

On Monday, the National Marine Fisheries Service said researchers hope to use DNA testing to identify the third whale, which was found floating Oct. 14 about 100 miles east of Nantucket. The whale had been dead for one to four weeks when it was examined, and the decomposed carcass carried no entangling rope when it was found, spokeswoman Jennifer Goebel said. But deep imprints on the animal’s body showed that ropes had tightened around and cut into its chest and flippers. 

“The necropsy team can’t say for sure how the entanglement affected this particular animal — whether it drowned quickly or what its movement may have been when it was alive and entangled,” Goebel said. “We just don’t have enough information. Generally, entanglements can affect the whale’s ability to migrate, to feed, to breathe. Even if an entanglement does not cause death, it can affect a whale’s health by constricting its movements, feeding, breathing, et cetera.”

The dead whale was at least 35 feet long, meaning it had not yet grown to adulthood. As scientists work to identify the whale through DNA and a comparison of records for known North Atlantic right whales, that could provide information about when and where it was born, whether it was a male or female and its family tree.

Scientists are particularly concerned about a decline in females and in the lack of calves born during the 2017-18 calving season.

“We still have a fair number of females, about 100, that ought to be capable of reproducing,” Mayo said.

After such a poor calving season a year ago, researchers will look for a resurgence of mother-and-calf pairs off the coast of Florida and Georgia within the next few months, Mayo said. The right whales typically migrate seasonally along the East Coast and arrive in Cape Cod Bay to feed in the late winter and early spring.

https://www.capecodtimes.com/news/20181107/new-estimate-lowers-number-of-right-whales