The word came through Friday, a time in which news typically tends to get ignored as people begin their weekends. But whales don’t live by human society’s constructs, and go about their business regardless. So it was, then, that a conservation team discovered the first right whale calf seen off the South Atlantic coast in close to two years.
“The weather outside may be frightful, but endangered species observers with Coastwise Consulting were hard at work aboard the dredge Bayport when today, they spotted the first North Atlantic right whale calf of the 2018-2019 season,” the Florida Fish and Wildlife Conservation Commission’s Wildlife Research Institute posted to Facebook Friday. “The whales were sighted near the St. Johns River entrance, slowly moving north.
“The mother, Catalog No. 2791, was seen just five days ago off Georgia.”
According to the North Atlantic Right Whale Catalog, No. 2791 is more than 20 years old, first observed by staff from the New England Aquarium in the Bay of Fundy in August 1997. She was seen in the South Atlantic calving grounds for the first time in January 2006.
No. 2791 returned south again in January 2009, but after the trip back north that year, she was seen a few times in 2010 and 2011, then went unobserved from February 2012 — in Cape Cod Bay — to May 2016, just south of the Gulf of Maine. Her observation off the Georgia coast last week was the first in the calving grounds in almost 10 years.
If No. 2791 truly has not been in the area since January 2009, it fits with the lengthening of calving cycles noticed by whale biologists over the last several years.
When right whales calve, they first put on a heavy amount of weight, feeding off the coasts of New England and Canada’s Maritime provinces. After they swim south and calve, they do not feed, but instead live off the weight accumulated, while nursing their calf, until both return north.
According to a report released by NOAA Fisheries in September, studies from 2015 and 2018 revealed that, looking at 30 years of data, “prey availability is a driver of decadal differences in the right whale population’s recovery.
Periods of low prey availability coincided with reduced birth rates … and the interval between births has been observed to lengthen during periods when prey availability is low….”
In essence, calving cycles that used to be three-to-four years have lengthened to around 10 years. With the warming of the Gulf of Maine, plankton favored by right whales have migrated north, which — for those feeding in that area — means less available food. For those that follow the plankton north, that puts an increased burden on the energy needed to swim south and back again, all while nursing a calf on the return trip.
And as always, entanglements in fishing gear continue to pose problems.
“With the calving interval now nearly twice as long as in the past, half as many calves are being born,” according to the NOAA Fisheries report. “So while entanglements often do not kill an animal, they may have a large impact by reducing or preventing births in the population. There is an additional variable, stress, which is much harder to quantify but known to have costs in mammals that are foraging in an environment with some mortality threat.
“It is difficult to tease out the relative effects of poor foraging conditions and the energetic costs of entanglement on the increased frequency of thin whales and the subsequent decrease in calving. Both are likely having some influence. While there are dozens of documented cases of ship strikes ad entanglement linked to right whale mortality, to date there is no confirmed observation of a right whale starving to death from poor forage.”