I didn’t specifically set out to work on bears. Biology is my passion but, like many people who work on polar bears, once you begin studying them you really get hooked – there is so much we don’t know about this remarkable species.
Here in Baffin Bay we’re conducting a population inventory. Our primary objective is to determine the overall size and condition of the population, specifically: how many bears there are and how well they are reproducing and surviving. The study area for the project extends from the east coast of Baffin Island to Greenland, south to Davis Straight and north towards the entrance to the Northwest Passage in Lancaster Sound. The research is being conducted for the Governments of Nunavut, Canada, and Greenland, all of whom have some degree of responsibility to conserve and manage these polar bear populations.
“Today, polar bear numbers appear to be higher than they have ever”
This particular project has a unique aspect to it. Normally when we study polar bears we tranquilize and capture them to collect our data. Each animal is given a set of numbered ear tags and lip tattoos that allows us to identify them if captured again in the future. However, the entire program in Baffin Bay was accomplished without handling any polar bears. Instead, we used DNA as a way of identifying each bear; essentially the DNA served as a unique genetic mark or ‘fingerprint’ that substituted for the plastic ear tags we would normally use.
To get DNA from a polar bear without capturing it is not as hard as it might sound. First we approach the bear in a helicopter. From a distance we fire a biopsy dart from a rifle. When the dart impacts the bear it pinches a small piece of skin (about 4mm in diameter) and then falls to the ground. Afterwards the bear is able to walk away, a little shaken up but unharmed, and we are able to pick up the fallen skin sample. The DNA provides researchers with “core information:” the sex of the bear and its identity. While taking the biopsy sample we also visually assess the bears to collect information about body condition, estimated age, and the number and age of cubs.
Over the last 3 years we have genetically fingerprinted well over a thousand bears in this population. Looking at the number of bears we have fingerprinted and how many times we have encountered each individual, we can calculate things such as the total number of bears in the region. This method of estimating population size, called mark-recapture, has been used all over the world to monitor wildlife populations. Baffin Bay represents the first intensive and population-wide effort to use genetic mark-recapture.
Over the years methods for capturing polar bears have been refined and are very safe for both people and bears; although the very first time that I captured a polar bear it was quite nerve-wracking – I was so concerned about injuring the bear! As biologists we’re very concerned about the welfare of the animals we study and are always seeking to minimize stress on them. Any human contact with a polar bear, whether it’s flying over it or tranquilizing it, is going to amount to a degree of temporary stress; but it comes down to a question of degrees. By using biopsy darts, we can reduce contact with the animals and minimize stress on them. For example, biopsying a polar bear puts us in contact with that animal for several minutes. In contrast, capturing a polar bear involves a pursuit, the time for the tranquilizer to take effect, and a handling period to collect data. Contact time can range from 20 minutes to an hour. So biopsy darting is a lot faster and presumably a lot less stressful.
“Over the last few decades the polar bear has become a symbol of the climate change issue”
But, there’s a trade-off. By using biopsy darting to reduce stress, we aren’t able to collect as much detailed information. This limits what we can find out about the condition of a population. In some cases there might still be a need to capture bears to collect more detailed data; things such as body weights, blood and fat samples for health studies; so I think in future researchers will use a combination of methods.
Polar bears tend to receive more attention than other Arctic animals. I think there are a variety of reasons for that. As a large, white, charismatic carnivore, they capture people’s interest across the world. From a biological perspective, they are a long-lived, slowly reproducing species, compared to other animals such as the arctic fox. Theoretically this makes polar bears more susceptible to the effects of human disturbances including things such as hunting or habitat degradation. As a result, a lot of attention is paid to populations that may be in decline; the concern being whether or not the decline is part of a natural cycle or the result of human influences. All of this attention has had a positive effect, making polar bears one of the most closely monitored and well-managed species on earth and making studies like ours possible.
Over the last few decades the polar bear has become a symbol of the climate change issue. This has greatly increased the demand for information about the species, especially because the potential effects of climate change on polar bear populations are not necessarily easy to detect. This has led to an overall increase in monitoring efforts in Canada, where most of the world’s polar bears live.
One of the predictions of climate change is that there will be less and less multi-year ice and more first-year ice in some parts of the Arctic. Some hypothesize that the increasing amounts of first year ice will initially be beneficial for seal and polar bear populations, causing a rise in the number of seals and bears in areas of first-year ice. To understand this a little bit better, imagine yourself as a polar bear. One of the ways you hunt is by breaking through sea ice into a seal lair to catch a meal. Today the ice is really thick so you’re having a hard time breaking through it. If it were a little thinner it would be easier. Seals and polar bears don’t generally like multi-year ice because it tends to be very thick; bears can’t break through it and seals can’t maintain breathing holes, or birthing lairs underneath it.
“Some hypothesize that the increasing amounts of first year ice will initially be beneficial for polar bear populations”
Of course if the sea ice continues to deteriorate then you’ve got more open water. From there, you can imagine that an animal that hunts and walks on ice will have a harder time feeding and surviving in an environment without ice. This will result in a decline in the number or distribution of polar bears or both. In other words, they will go where the ice is, and where the ice isn’t there will be fewer of them. The logic is simple; less ice, less bears.
It’s important to understand how changes in the environment might affect polar bears and make predictions about the future of the species. But predictions need to be tested to know whether they are coming true or not. As wildlife managers or conservation biologists we can’t manage what might happen 50 or a 100 years from now. The key is to monitor and understand what is happening right now and respond appropriately, which is why the Baffin Bay Biopsy Project is important – this type of research gives us the current numbers and trends; information we can use to take action now. Today, polar bear numbers appear to be higher than they have ever been since detailed records were first kept. Close monitoring through projects such as ours will help keep track of the species.
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