Quirks & Quarks

Right whales were in the wrong place because of the wrong climate

Warming water in their traditional habitat led to a collapse in their favourite prey

Warming water in their traditional habitat led to a collapse in their favourite prey

Right whales have been dying in high numbers, and reproducing in extremely low numbers since 2010. (Lisa Conger/Northeast Fisheries Science Center under NOAA Permit #17355)

Researchers have discovered that endangered North Atlantic right whales might have moved into dangerous waters in the Gulf of St. Lawrence because climate shifts disrupted their food source.

North Atlantic right whales have historically summered in and around the Gulf of Maine and the Bay of Fundy. Special efforts including regulation of ship traffic and fishing have been made to accommodate the endangered whales, whose total population is just over 400 animals.

2017 a catastrophic year for the whales

In recent years, the whales began to move away from this summer habitat, and in 2017, a larger number of whales appeared in the Gulf of St. Lawrence.  This led to several ship strikes and fishing gear entanglements, plus the deaths of 12 whales that was in addition to the six whales who died in US waters.

On top of that, 2017 and 2018 were terrible reproductive years for the whales, with only 5 calves born in 2017 and none in 2018.

Right whales are at risk of fishing gear entanglement throughout their range, but management authorities can restrict fishing in areas where they are expected to be foraging (Center for Coastal Studies/NOAA permit #932-1905)

Now a team of researchers that included Kimberley Davies from the University of New Brunswick has built a case that might explain why the whales abandoned their traditional feeding grounds.

Davies told Bob McDonald in an interview on Quirks & Quarks that her team found that warmer waters circulating in the Gulf of Maine starting around 2010 seem to have depressed the population of a small, shrimp-like copepod that is an important food source for the whales.

New habitat brought new risks

The whales were then forced to search other waters for a new food source. They found it in the colder waters of the Gulf of St. Lawrence, where a related copepod currently thrives. However this new feeding habitat brought a new set of risks.

Since the whales' unexpected appearance in the Gulf of St. Lawrence in 2017, new regulations have been put in place to protect the whales in what appears to be their new feeding grounds.  Shipping speeds have been limited, and areas where the whales have been predicted to appear have been closed or restricted to fishing.

Davis said she and her colleagues are continuing to work to understand the oceanographic conditions that drive the whales to move into different areas so they can better predict their movements and perhaps avoid a repeat of the disastrous year in 2017.



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