It appears that there has been some North Atlantic right whale whoopee going on, but whale researchers on Wednesday cautioned against viewing the recent sightings of six right whale calves as a sure sign of resurgence for the beleaguered species.
Whale researchers on Tuesday confirmed the sighting of the sixth right whale calf off the coast of Florida, elevating the 2018-2019 calving season above each of the past two years, but still well below the 20-year average of 17 calves per calving season.
"It's definitely not enough to take the view that things have turned around for right whales," said Philip Hamilton, a research scientist at the New England Aquarium's Anderson Cabot Center for Ocean Life.
Right whales migrate along the Atlantic coast each year, arriving in New England waters to feed in the late winter and early spring, congregating on Stellwagen Bank and off Cape Cod. They migrate south in the fall to give birth off Florida and Georgia.
Going into this calving season, whale researchers estimated there are only 411 North Atlantic right whales remaining in the oceans, down from about 500 in 2010.
The imperiled state of the North Atlantic right whale stock has thrust fisheries regulators, such as NOAA Fisheries, conservationists and fishing stakeholders into action to try to reverse the dire trend of a shrinking right whale population.
So, producing any right whale calves during the 2019 calving season— which runs roughly from Dec. 1 until late March —remains something of a cause for celebration. It represents a significant improvement over 2018, when none were born, and a (to date) modest increase over 2017, when five calves were born.
There is approximately one month remaining in the calving season, but Hamilton said pregnant right whale females generally give birth at the beginning of the season.
"On average by now, at least half the calves born in a calving season would be born by now," Hamilton said. "It's unusual to get a large bump later on in the season."
But, Hamilton added, historical reproductive behavior shows the improvement in right whale reproduction from the past two years could be a sign that the pool of reproducing right whale females may be growing larger.
"In the late 1990s, there was a similar drop in reproduction," he said. "In 1998, there were five calves born. In 1999, there were four and only one in 2000. But there were 31 calves born in 2001. So, we might expect to see a pretty robust rebound. Many of the mothers have had a two-year rest, which often means they're ready to get pregnant again in the third year."
Whale researchers keep a close eye on the average calving intervals for right whale females. Hamilton said the average interval for the five females that gave birth to calves in 2017 was 10 years, meaning they had gone a decade between calves.
"This season, one of the females is on a 3-year interval, which is much better than 10," he said.
The most recent addition to the North Atlantic right whale population was swimming with its mother Tuesday when spotted off Flagler Beach, which is about halfway between St. Augustine and Daytona Beach on Florida's east coast.
Researchers with the Marineland Right Whale Project, according to the Daytona Beach News-Journal, later said their photo analysis of the whale tandem identified the mother as whale No. 3370. They said it is her second calf.
The Atlantic States Marine Fisheries Commission said last week its American lobster management board is considering new measures to reduce the amount of vertical fishing lines in the water as a further protection for right whales.
Contact Sean Horgan at 978-675-2714, or firstname.lastname@example.org. Follow him on Twitter at @SeanGDT.