Bowhead whales cross from Atlantic to Pacific regularly

First range-wide study of bowhead whale genetics finds much genetic diversity lost during age of commercial whaling

October 2012. Scientists from the Wildlife Conservation Society, the American Museum of Natural History, City University of New York, and other organizations have published the first range-wide genetic analysis of the bowhead whale using hundreds of samples from both modern populations and archaeological sites used by indigenous Arctic hunters thousands of years ago.

A newly published study by the Wildlife Conservation Society, the American Museum of Natural History, and other groups represents the first range-wide genetic analysis, using both modern-day tissue samples and historical artifacts of the bowhead whale, a species at home among the ice floes of the Arctic. This individual was photographed off Point Barrow, Alaska. Reaching up to 65 feet in length and up to 100 tons in weight, the bowhead whale is a baleen whale that lives in Arctic and sub-Arctic waters. The bowhead gets its name from its enormous arched head, which it occasionally uses to break through ice up to 60 centimetres thick in order to breathe.

The species widely hunted for centuries by commercial whalers, who prized the species for its long baleen (used in corsets and other items) and its thick blubber (the thickest of any species of whale). The bowhead whale may also be among the most long-lived mammal species. In 2007, aboriginal whalers on the Alaskan coast landed a whale carrying a valuable clue about the animal’s probable age. The whalers discovered a harpoon point manufactured in the 1890s embedded in the whale’s blubber, indicating the animal may have survived an encounter with whalers more than one hundred years ago.

Ancient DNA samples
In addition to using DNA samples collected from whales over the past 20 years, the team collected genetic samples from ancient specimens -extracted from old vessels, toys, and housing material made from baleen-preserved in pre-European settlements in the Canadian Arctic. The study attempts to shed light on the impacts of sea ice and commercial whaling on this threatened but now recovering species. The study appears in the most recent edition of Ecology and Evolution.

"Our study represents the first genetic analysis of bowheads across their entire range," said Elizabeth Alter, the study's lead author and now a professor at City University of New York. "The study also illustrates the value of ancient DNA in answering questions about the impact of changing climate and human exploitation on genetic diversity in bowhead whales."

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