Back Forty: On the trail of the right whale

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By Bridget Huber

In January, Song of the Whale, a 70-foot research sailboat, embarked on a months-long study of the critically-endangered North Atlantic right whale. Researchers will identify whales, record the sounds they make, and study human threats to their survival. The team is even prepared to “babysit” new mothers and their calves in areas with heavy boat traffic.

Fewer than 340 North Atlantic right whales remain; scientists say the primary threats to the species are entanglements in fishing gear and being hit by passing ships. We are midway through calving season, which runs from November to April and takes place off the southeast coast. So far, a dozen calves have been born. But at least three right whales have been spotted newly entangled in fishing ropes since the beginning of the year; one entanglement is so severe that the whale is expected to die. On Sunday, a dead adult right whale washed ashore in Virginia Beach, Virginia, and last month a newborn calf was found dead off the coast of North Carolina.   

The voyage, a partnership between the International Fund for Animal Welfare and Marine Conservation Research International, started in Florida and will follow the whales’ migratory route, which hugs the eastern seaboard up to Canada. Along the way, the ship will hold public events at several ports. Later this month, it will sail up the Potomac to Washington, D.C.; the public is invited onboard on February 27 to tour the boat and learn about its right whale research.

I spoke with Oliver Boisseau, senior research scientist for Marine Conservation Research International, when the boat docked in Beaufort, North Carolina, in early February. Our conversation has been edited for length and clarity.

Can you tell us about what you’ve seen so far?

We saw quite a few right whales off Florida and Georgia — mothers and calves and also a few other adults. We’ve been working closely with teams running aerial surveys in the Southeast, and this is an excellent way to find the animals, particularly the mothers and calves, and to identify individuals. One of the great things about right whales is they are individually recognizable by the unique markings they have on their heads and faces. There’s an ID catalog that’s maintained by the New England Aquarium so we can readily identify the animals we see, and some of the local experts can even recognize some individuals by sight. Though that is, I suppose, a testament to how much the population has dwindled.

You were involved in a disentanglement of a whale called Nimbus?

Yes. We worked closely with the local teams in a supporting role. Disentangling is really a job for the professionals because it’s possible to harm both the whale and the human in the rescue operation. Nimbus had fishing ropes out of both corners of his mouth, and the local team cut 375 feet of rope from him, though he still has a small bit attached. We’re hoping that Nimbus has more of a fighting chance now.

Disentanglement can take months or even years. Last year, a female in the population called Snow Cone, that had a long-standing entanglement, began to decline. Then she subsequently disappeared from the population. So we assume she is dead. That was very sad, especially since she did have a calf last year. And unfortunately the calf also has no longer been seen.

Can you give us a sense of what kind of research you’ll be doing and how that might help these whales?

We’re primarily interested in acoustics — recording marine mammals and using their vocalizations to interpret their world. Cetaceans — whales and dolphins  — rely on acoustics to communicate, navigate and find prey. We are towing a hydrophone array, an underwater series of microphones that are particularly sensitive to the lower frequency vocalizations that baleen whales make. One of the main vocalizations North Atlantic right whales produce is called an up-call. It sounds to my ears like a cow mooing. But there’s some evidence that mothers and calves also produce very quiet vocalizations – they’re whispering to each other.

One of the strategies for protecting right whales is the use of early warning systems — buoys equipped with acoustic devices that can detect their vocalizations near major harbors and marinas. If the buoy detects an up-call from a right whale, the Coast Guard is alerted so they can warn boats to slow down or perhaps change course. This is seemingly quite an effective and proactive way to help reduce ship strikes. But unfortunately, the algorithms the systems use to detect the whales are mostly looking out for the up-calls and not the whispering of mothers and calves. In a perfect world, we’d have the mother and calf vocalizations detectable by this early warning system, since they are the most valuable members of the population.

In cases where a cause of death can be determined, 90 percent of North Atlantic right whale deaths are attributed to entanglement in fishing gear or ship strikes. But climate change also may be playing a role in their decline—can you explain?

There’s been a large-scale shift in the distribution of right whales. Traditionally, their main summer feeding grounds were in the south of Canada, notably the Bay of Fundy. But in 2015 the whales abandoned this area and quite abruptly moved much further north into the Gulf of St. Lawrence. We think this was linked to a warming event. Right whales tend to feed on just one species of plankton called a copepod. And copepods tend to bloom in large numbers in cooler water. So when the water warmed, it meant the right whales had to move north to find their food. But the Gulf of St. Lawrence is a major thoroughfare for shipping and it has a major snow crab fishery. So suddenly, in 2017, there was a large number of deaths. Though, in Canada’s defense, it very quickly took measures to reduce ship strikes and entanglements.

So aside from the deaths in Canada, the stress of having to find new feeding grounds may also have hurt the population overall?

Right. We suspect that the population took a bit of a hammering around then because they had to find a new feeding ground. The whales didn’t have that cultural knowledge to find their prey in a new environment. So in 2018, no viable calves were born. And alarm bells start to ring as soon as we get fewer than 10 calves in the population.

This year, there have been a dozen births, though that’s still not enough to reverse the whales’ decline. How are you feeling at this point in the expedition?

It’s hard to remain positive. The species is on a knife’s edge. Some of us on the vessel are seeing whales we were working with 20 years ago, so it’s a chance to see what changes, if any, have taken place. And the population has declined. It’s been a bit frustrating; some of the issues we were talking about 10 years ago are still issues.

We often see whales with visible scars on their heads from previous entanglements in fishing gear. Sometimes we see propeller marks on their backs. It’s quite sobering to see the animals up close again, and to be reminded that they are carrying the scars, literally, with them. Their bodies themselves tell a story.