Snot for science: Arctic researchers are collecting snot from beluga whales to study stress
by Justine Hudson
When a whale surfaces to breathe, it exhales thousands of tiny drops of respiratory condensate, also known as “blow” or “snot.” Blow contains a wealth of biological information and has been used to study stress, reproduction, genetics, disease, and the microbiome of whales all over the world. In Churchill, Manitoba, researchers are collecting blow from beluga whales to measure baseline stress levels to better understand the impacts of a changing climate.
When we think of stress the first thing that comes to mind may be the stress that we experience from work or school. For marine mammals, however, stress comes in the form of pregnancy, mating, disease, lack of food, and becoming food for someone else.
In the Arctic, temperatures are rising at twice the rate of the global average and the ice-free season is becoming, on average, 5 days longer per decade. This means that Arctic marine mammals have to cope with additional stressors such as prey fish moving northward; an influx of killer whales, which prey on Arctic marine mammals; and an increase in shipping activity, which in itself poses numerous risks.
Stress isn’t inherently bad. We’ve all experienced a heart rate increase after hearing a strange noise while we’re home alone. This fight-or-flight response is good for us, as it tells us that we should be vigilant and aware. On the other hand, long-term stress can have negative health consequences and has been associated with heart disease, decreased immune function, and infertility in humans.
Studying the health of whales isn’t easy. They are large, free-swimming, diving animals, making them hard to observe and even harder to collect samples from. Combine that with a layer of sea ice and extreme weather conditions and Arctic whales become even more difficult to study.
Stress in marine mammal populations has been studied using feces, blood, blubber, and skin. However, many of these methods actually cause a stress response, making it difficult to interpret the results. Using blow to study stress has allowed researchers to collect samples non-invasively, thus avoiding the potential of causing a stress response.
In 2017 we traveled to Churchill, Manitoba, home of the Western Hudson Bay beluga population — the largest population of beluga in the world. Our goal was to collect beluga blow to measure baseline stress levels.
You might ask yourself, how exactly do you collect whale snot? Well, the first thing that we had to do was to create a collection device, also known as the handkerchief. A variety of materials have been used to collect snot, including bridal tulle, pantyhose, petri dishes, and more recently, drones. After a couple trips to the local hardware store and many quizzical looks from the store’s employees, we built our device by attaching a piece of fibreglass to an extendable painter’s pole and using Velcro to attach petri dishes.
In the field, our days started off by loading our gear into the zodiac and boating down the Churchill River estuary, keeping an eye out for signs of beluga such as clouds of blow rising from the water.
Beluga are curious animals that enjoy playing in the wash from the engine of boats, so we used this to our advantage. We patiently waited for a beluga to approach the rear of the boat and then we opportunistically placed the collection device over the blowhole and waited for an exhalation.
It was a good day in the field if we collected blow samples, saw a polar bear or two, and could see through the cloud of mosquitos, black flies, and bulldogs (horseflies).
Our field season consisted of 24 days on the water, with a total of 28 days in Churchill. We collected blow samples for four hours each day during high tide, as it was easier to get the zodiac into and out of the water. We successfully collected 233 blow samples for the first time from unrestrained, wild beluga.
There were a few instances where we knowingly collected blow from the same individual but, because the Western Hudson Bay beluga population is so large, we don’t have a catalogue or database of known beluga. Thus we don’t know how many individuals we collected from.
To deal with this issue, we plan to use genetics and hormone assays to determine the sex and the reproductive state of each beluga, which is important to know as stress often differs between males and females and between pregnant females and non-pregnant females. To study stress, we’ll use hormone assays to measure stress hormones such as cortisol and corticosterone, which increase when an animal is subject to a stressor.
Beluga are known as the canaries of the sea because they seem to sing underwater. But they might also be canaries in the coal mine when it comes to understanding the impacts of climate change and environmental stressors. By collecting beluga snot and measuring stress, we hope to better understand the impacts of environmental stressors on the health of the Western Hudson Bay beluga population and beluga populations across Canada.
Justine Hudson is completing her M.Sc. at the University of Manitoba in collaboration with Fisheries and Oceans Canada.
