The fate of one of the world’s largest living animals depends on one of the smallest.
Scientists are studying a northward shift of the North Atlantic right whales and their speck-sized prey that could push one of the rarest whales on the planet closer to extinction.
Their main food, Calanus finmarchicus, commonly called copepods, a type of tiny zooplankton, is showing up in higher concentrations in the Gulf of St. Lawrence than in areas traditionally frequented by the endangered whales, such as the Gulf of Maine and Bay of Fundy.
The shift has put the whales in waters rife with shipping and fishing-gear hazards — with deadly consequences for the already endangered population.
DEEP TROUBLE | Right whale in peril
After an unprecedented number of deaths this summer, CBC News is bringing you an in-depth look at the endangered North Atlantic right whale. This week, in a series called “Deep Trouble,” CBC explores the perils facing the right whales.
Eleven whales, of the estimated 500 remaining, have been confirmed dead in the Gulf of St. Lawrence this summer.
“It’s getting really warm in the Gulf of Maine, and it’s warming faster there than anywhere else around,” said Stéphane Plourde, a Fisheries and Oceans researcher.
“The Calanus don’t prefer those conditions.”
The 60-tonne North Atlantic right whale feeds on prey that are normally less than a millimetre long. The tiny crustaceans float in the water by the billions.
Right whales swim through large pockets of the copepods, gulping up millions per mouthful, before sifting out excess seawater.
Although copepods are found throughout the North Atlantic Ocean, whales need dense plumes of them in order to gain energy from each deep feeding dive.
This summer it appears this need led the whales to the Gulf of St. Lawrence, where the copepods were plentiful.