Tuesday, July 24, 2012

Giving Beluga Whales a pill


If you think it's hard to hold a golden retriever long enough to make it swallow a pill, try harnessing a 1,200-kilogram, four-metre-long beluga whale.
That's what Winnipegger Chris Debicki tried to do more than 50 times earlier this month in the frigid waters of northern Manitoba's Seal River estuary as part of a beluga-tagging expedition.
During the subarctic summer, an estimated 57,000 white whales inhabit the waters of western Hudson Bay in a long arc of coast that extends from Arviat, Nunavut, to just across the Ontario border.
Where exactly the whales swim to is a bit of a mystery, however, as biologists are not certain whether the marine mammals hang out at the mouths of the same rivers all summer or move around the coast.
Knowing where the males go is important as conservation officials prepare for the possibility of more shipping in Hudson Bay, where the ice-free period is getting longer.
Hence the expedition to the mouth of the Seal River earlier this month, where a joint crew of federal fisheries officials, provincial scientists and staffers from marine-conservation organization Oceans North Canada succeeded in placing satellite transmitters on six beluga whales over the course of a week.
"We call that a success," said Debicki, an Oceans North project director who was handed the task of grappling with the whales because he was one of the few non-scientists on the expedition.
Tagging adult belugas is not an easy task, even though these whales display little fear of people. The expedition broke six propellers and one driveshaft on a pair of zodiac boats as they tried to corral belugas in the shallow waters of the Seal River estuary, working at low tide.
It was Debicki's job to jump off the Zodiac into the shallow water and attempt to place a hoop net around a whale. More often than not these attempts failed, he said.
The six whales the expedition did manage to capture were tagged with lithium-powered satellite transmitters capable of operating for more than a year. Since beluga whales have no dorsal fins, the tags are implanted in a hard ridge of fatty tissue on their backs the creatures use to break the ice.
A veterinarian stood by to ensure each whale was enduring the procedure, Debicki said.
"Right until we catch them, they're not very stressed at all, it seems. And if they got away they would stay with us," he said. "But they're obviously not thrilled to be in a hoop net."
The Seal River estuary is one of three major beluga whale gathering spots in Manitoba, along with the mouth of Nelson River at York Factory and the Churchill River estuary near Churchill.
Scientists tagged belugas near Churchill in 1993 and on the Nelson River from 2002 to 2005, said Oceans North biologist Kristin Westdal. The latter effort demonstrated the whales spend their winters in stretches of open water in the Hudson Strait.
According to satellite monitoring, the first tagged whales on the Seal River spend a tremendous amount of time in the river itself, Westdal said.
This may because the fresh water is warmer or because the shallow, sandy river bottom aids the moulting process, she said. The shallow river may also offer protection from predators such as killer whales, which do not do well in ice but appear to becoming more common in Hudson Bay.

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