Narwhal Nursery Located In Busy Canadian Waters; Are the Elusive Sea Animals At Risk?
Aerial photographs taken of the Canadian Arctic reveal a surprising discovery: a nursery for one of the world's most elusive animals, the narwhal. Narwhals, also known as "unicorns of the sea," spend nearly 80 percent of their time under water and for more than half the year during the dark Arctic winter are hidden under dense sea ice. Needless to say, protecting the animals proves quite the challenge, mostly because researchers are not even sure how many exist.
But scientists from McGill University in Montreal, Canada, recently learned a little more about these elusive marine creatures by focussing on the number of baby narwhals. This is a major step towards understanding the stability of narwhal populations.
During the summer, narwhals emerge from ice-covered waters and migrate to coastal inlets, where they give birth – providing scientists with the opportunity to count them. About every five years, Fisheries and Oceans Canada (DFO) collect aerial photographs to get a better idea of the number of narwhals living in the Canadian Arctic, an area that houses nearly three quarters of their global population.
Bertrand Charry of McGill University and colleagues examined photographs taken during the 2013 DFO aerial narwhal survey over Eclipse Sound and Admiralty Inlet, off the northern part of Baffin Island in the Canadian Arctic. Based on size and color – baby narwhals are blue-gray, while adults are typically a mottled gray – along with proximity to their presumed mothers – calves normally stay within two body lengths of their moms – researchers were able to count the number of newborns present in these two areas.
The results, however, revealed a surprising difference in distribution. Roughly 35,000 narwhals were found in Admiralty Inlet, but newborns made up just 0.05 percent of this population. The Eclipse Sound in home to a smaller population – 10,000 narwhals of which about five percent were newborns. This suggests the area may be an important calving and nursery habitat.
This information may help the DFO create more effective narwhal catch limits. For instance, reducing the catch limit in the Eclipse Sound could cut down on the separations of the young from their nursing mothers.
Eclipse Sound is located within the shipping route of a new Baffinland iron-ore mine. The increased boat traffic and noise pollution there could have a major impact on narwhals because, like all whales, "narwhals are a sound-centered species," Valeria Vergara of the Vancouver Aquarium told New Scientist. "Mothers and calves are a critical sector of the population, and shipping noise could affect the ability of mothers to hear their calves."
Unfortunately, narwhal struggles don't end there. Warmer waters and melting sea ice, invite large predators into the Arctic. A recent study found the expansion of killer whales into Canada's Hudson Bay makes easy prey of beluga whales, narwhals and several other species.
It's hoped that understanding more about Canada's narwhal population will help researchers implement more effective conservation practices. Charry recently presented his findings at the annual ArcticNet scientific meeting in Vancouver.
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