With only six calves sighted this season, it was a disappointing winter for right whale researchers.
“It was way below the average of 20 per year we’ve seen for the last decade,” said Clay George, who heads up right whale monitoring and research efforts for the Georgia Department of Natural Resources.
North Atlantic right whales head south from summer feeding grounds in New England and Canada to the waters off south Georgia and north Florida every winter to give birth to their calves. With an estimated 450 individuals remaining, the animals are considered the most endangered of all large whales.
Research teams — including those from the DNR, the nonprofit Sea to Shore Alliance and the Florida Fish and Wildlife Commission — fly aerial surveys to document the whale activity. Overall sightings, as well as births, were low this season with 61 individuals seen, compared to last season’s total of 170 individuals including juveniles.
Of the six calves, one is believed to have died. It was the first calf seen, born to a 29-year-old nicknamed Half Note for the marking on her head. Half Note’s previous two calves, born in 2006 and 2008, also died on the calving grounds. Her first calf, born in 1989, is believed to have only survived two years. The cause of her reproductive difficulties is unknown.
Right whales are so named because they swim close to shore and float when killed and so were once considered the “right” whale to hunt. Whaling, banned in the U.S. in 1935, brought the whales to the brink of extinction. Current threats include collisions with boats and entanglement in fishing gear. Only one entangled whale was encountered in the Southeast this calving season, and it’s believed to have shed its ropes, George said.
Researchers say a lack of food in the whales’ summer feeding grounds in the Bay of Fundy in 2010 may be linked to this year’s overall baby bust. The whales’ gestation period is a year long, making that summer crucial in preparing the females for this winter’s calves.
The baleen whales feed on rice-sized zooplankton which typically thrives in the Bay of Fundy in the summer. In 2010, however, few right whales were seen in the bay. Instead, sperm whales, which feed on squid and large fish, were seen there for the first time in the 30 years of right whale monitoring.
“It seems like their food resources must be off,” said Amy Knowlton, research scientist with the New England Aquarium.
She’s hoping the whales don’t repeat a recent spate of poor calving performance.
“In the 1990s, we had four years that were quite low,” she said. “We had a total of 11 calves, which is not many. That’s why we’re concerned. Ideally this is a one-year decline. If it becomes four or five years, that’s not good; it compromises their recovery.”