Why Did So Many Right Whales Meet an Untimely End This Summer?

Source: Hakai Magazine/Sasha Chapman - October 11, 2017 in Science/Tech

Why Did So Many Right Whales Meet an Untimely End This Summer?
Photo: John Durban/NOAA/Wikimedia Commons (CC0)

After two months studying the carcasses of seven right whales found dead off Canada’s Atlantic coast this past summer, scientists have revealed what killed six of the endangered animals.

On October 5, Pierre-Yves Daoust, a pathologist at Prince Edward Island’s Atlantic Veterinary College, and Émilie L. Couture, a veterinarian at Zoo de Granby and Université de Montréal, released the results of their investigation into the unprecedented mortality event of this beleaguered species.

There was no evidence of biotoxins. No suggestion of infectious diseases. In fact, the findings were entirely predictable: internal bleeding suggested that four of the necropsied whales had died from blunt trauma, aka from collisions with ships. (Nothing else in the ocean is big and fast enough to do that kind of damage to a 65-tonne whale.) Two others had died from entanglement in snow crab fishing gear, though nearly all the carcasses had scars consistent with entanglement. The scarring was no surprise—as the report’s authors noted, 83 percent of right whales are entangled in fishing gear at some point in their lives. The seventh whale was so severely decomposed that the cause of death could not be determined.

Nearly all the whales examined had died as a result of human activity. As one of the report’s coauthors, Tonya Wimmer of Nova Scotia’s Marine Animal Response Society, says, “That’s not new information.”

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