In a series called Deep Trouble, CBC News explores the perils facing the endangered North Atlantic right whale.
Amid the deaths of North Atlantic right whales in recent years, there is at least one bright spot.
It comes wrapped in plastic and duct tape, couriered to eager researchers at laboratories in Boston.
Whale baleen removed from North Atlantic right whales during necropsies will soon be studied to help sleuth details of their lives and deaths and may be able to help the remaining 400 or so members of this critically endangered species.
“The best way that we could honour the life of these animals is to use their death for good,” said Nadine Lysiak, assistant professor at Suffolk University in Boston. “We can hopefully prevent it from happening to others and increase our knowledge of the population, which is having such a terrible few years lately.”
There have been eight right whales found dead in Canadian waters since June. In 2017, there were 12.
Baleen is the hairy-looking stuff that hangs down from a whale’s upper jaw to help it catch plankton, krill and other tasty creatures. Made of keratin, a protein that also comprises human fingernails and hair, it grows throughout the life of the whale up to a length of about 2.5 metres.
In fact, it’s similar enough to human hair that, when Lysiak received a baleen sample from a whale that died in 2005, she washed it with shampoo to remove sand and grit before starting her work.
Unlike fecal samples and droplets of respiratory vapour emitted from the whale’s blowhole — which give researchers a snapshot of information about the whale’s health — these long plates of protein act as more of an entire photo album of its life.
Scientists like Lysiak conduct chemical analyses on slices of baleen plates, studying hormone levels to learn about the whale’s feeding habits, reproduction and stress levels over 10 or so years.
“Baleen’s kind of cool because you can go back in time,” Lysiak said. “Baleen is this continuous sort of retrospective record about what an animal has been doing up until the time that you got that baleen sample.”
Getting the samples, though, is no easy feat, as baleen decomposes quickly in the water after a whale’s death and is firmly rooted in the whale’s jaw.
“You end up using knives, hammers. We have big saws,” says Tonya Wimmer of the Marine Animal Response Society in Halifax, the group that obtained the baleen samples and is sending them to researchers. “It takes two and three people rotating around because it’s all so exhausting for them to basically be able to hammer and chisel it out, essentially.”
Estrogen and progesterone levels in baleen reflect a whale’s history of pregnancy, which could be an important clue in the mystery of the declining birth rate of the species, said Rosalind Rolland, a senior scientist at the Anderson Cabot Center for Ocean Life at the New England Aquarium.
“So one of the questions is, are they getting pregnant at all and losing their calves or are they just not even getting pregnant?”
Rolland said a healthy right whale population sees females calve every three to 3½ years, but females are now calving on average every 10 years.
Thyroid hormone levels in baleen can show how much or how little a whale has eaten, pointing to periods of food limitation, starvation or entanglements around the mouth.
Since hormones like cortisol and corticosterone increase when a whale is under stress, they can reveal information about entanglements and other stressors. Vessel strikes, however, are not usually detectable in baleen because whales often die quickly after being hit, and there is not enough time for the stress response to be recorded.
Lysiak has also been studying stable isotopes, biomarkers left in baleen from food sources that can be used to pinpoint where a whale was foraging. That information could be useful for helping draft fisheries regulations and whale conservation measures.
“Can we go back in time through the baleen and get a better sense of where they might have become entangled?” said Lysiak. “Oftentimes when you see an entangled whale, it’s not possible to connect the gear back to a particular fishery or a particular fishing ground. So we often have to make really sweeping management regulations without knowing that particular information.”
Rolland said her research over the years has focused on developing ways to figure out whether human activities such as fishing, noise in the ocean and construction of wind farms are affecting whales’ health. Baleen analysis is a “cutting-edge technique” that can help, she said.
“With enough data we can start to make inferences about what are the factors out there that are most affecting this population negatively.”
Lysiak and Rolland also hope to examine baleen in museums from hundreds of years ago to try to understand changes in the population over time.
Article source: https://www.cbc.ca/news/canada/nova-scotia/whale-baleen-north-atlantic-right-whales-1.5241106?cmp=rss