North Atlantic right whales have once again been spotted in New England’s waters, with several sighted south of Nantucket. These iconic large whales are known for gathering in Cape Cod Bay each spring, but their movements have been less predictable in recent years.
But the population is in dire condition.
It’s estimated there are just over 400 animals left, and that number is dropping, not rising. Researchers cite two major factors: very low birth dates, and high rates of deaths linked to fishing and shipping.
Now, a new study details why female whales are the key to saving this species.
The study looks at southern right whales, which are very closely related to their northern cousins. As you might expect, southern right whales live at the bottom of the globe rather than the top.
Southern rights die at a rate of one percent a year, while for North Atlantic right whales, the rate is three or four percent a year. The reason appears to be that there is less fishing and shipping in the southern oceans, meaning fewer chances for entanglement and ship strikes.
The paper’s lead author, Peter Corkeron of the Northeast Fisheries Science Center, was able to show that the North Atlantic right whale population should be growing at about twice the rate that it has over the last few decades. The difference is the high mortality of female North Atlantic right whales.
Studies of southern right whales has shown that, if the whales survive the first few years of life, there’s very little in the natural world that can kill them.
“They could live for almost 100 years,” Corkeron told Living Lab Radio. “It’s like they could be almost immortal.”
Other scientists have pointed out that a decrease in North Atlantic right whales’ food supply could be worsening the problem.
“If there is something about the amount of prey that’s out there or something, well, it’s pretty hard for us to do a lot about that,” Corkeron said. “Whereas we can do something about entanglement.”
Corkeron finds it promising that scientists and engineers are getting closer to coming up with fishing technology that would keep vertical trap lines out of the water, something called "rope-less fishing."
“I see no reason to not use optimism to try, because there's no point giving up,” he said.
