Changing oceanographic conditions mean whales are not where they once were
This summer, eight more endangered North Atlantic right whales were found dead in the Gulf of St. Lawrence. These latest deaths have increased the pressure on whale researchers to understand why the whales have begun moving so unpredictably in the waters around Eastern Canada.
The hope is if they can understand why the whales are moving, they can predict those movements and better protect the whales.
Kimberley Davies, a whale biologist from the University of New Brunswick in Saint John, along with colleagues from Dalhousie University and New England Aquarium in Boston, spent several weeks on a 20-meter crab fishing boat this summer studying whales that appeared in large numbers in the Gulf of St. Lawrence.
Up until about 2010, North Atlantic right whales spent most of their summer feeding and raising their young in the waters of the Gulf of Maine and Bay of Fundy. In these waters, the whales' movements were reasonably well understood, and limits could be put on shipping — to reduce risk of fatal ship strikes — and on fishing, to reduce the risk of dangerous entanglement in fishing gear.
But in more recent years, the right whales have been showing up in large numbers in the busy waters of the Gulf of St. Lawrence, and the result has been an increase in whale deaths — with a peak in 2017, when a dozen whales died in Canadian waters. Only about 400 whales survive, so these losses are unsustainable to a long-lived and slow-reproducing population.Davies and her colleagues have found that one significant reason for the whales' unpredictable movement is that their food source seems to be moving. The distribution of the tiny zooplankton called copepods that the whales eat has been shifting with changing oceanographic conditions off the east coast.
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