Scientists confirm traditional knowledge regarding seal pup migration

This map shows contrasts in travel between tagged seal pups in 2005 and 2015. These are portions of the pup tracks in November-December, after they left their birth islands. The tracks are overlaid on an 1895 chart displaying the understanding at that time of where northern fur seals traveled during their migration. (Courtesy Noel Pelland/Proceedings of the Tribunal of Arbitration at Paris, Volume 7.)

In the late 1800s, the U.S. Secretary of the Treasury sent Captain C. L. Hooper to the Pribilof Islands to learn as much as he could about the northern fur seal from the Alaska Native people who lived there. At the time, the fur trade was big business.

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One of the lessons he recorded was that the seals are known to travel with the wind when possible. Now scientists have the data to back up that traditional knowledge. Noel Pelland is a physical oceanographer and postdoctoral researcher at NOAA’s Alaska Fisheries Science Center.

“We have this amazing technology that really allows us this very cool look at the lives of an individual animal and where it goes and what it does,” Pelland said. “That’s helping us to quantify some of those things that have been discussed by the Aleut hunters.”

Pelland is studying how climate affects the survival of northern fur seals in the Bering Sea, and wind may be an important factor.

After pups leave the Pribilof Islands in late fall, they can migrate thousands of miles. Varying wind conditions mean pups can end up in a range of locations from the Aleutian Islands to the Gulf of Alaska.

Pelland wants to know if the way the pups migrate, and where they end up, is affecting their survival.

“In the best years about 50 percent of the pups that leave on their migration will make it to age two,” Pelland said. “In the worst years only about 20 percent of the pups will make it through their migration.”

So far, Pelland and his colleagues have compared data from satellite tagged pups with weather models. Now, they want to compare year-to-year changes in the survival of the pups with where the pups end up.

And Pelland says the research helps make the case for all scientists to take traditional knowledge into account.

“There’s this idea of a separation between ‘scientific knowledge’ and traditional knowledge. I think a much better way to look at it is as an continuum,” Pelland said. “There isn’t this formal separation. It’s all knowledge.”

Wind might not be a factor in the fur seal decline, Pelland says but a better understanding of its role is important.

Zoe Sobel is a reporter with Alaska's Energy Desk based in Unalaska. As a high schooler in Portland, Maine, Zoë Sobel got her first taste of public radio at NPR’s easternmost station. From there, she moved to Boston where she studied at Wellesley College and worked at WBUR, covering sports for Only A Game and the trial of convicted Boston Marathon bomber Dzhokhar Tsarnaev.

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