Return of Right Whales to Their Ancestral Territory

During their seasonal migrations, right whales follow their food. They feed mainly on copepods, namely Calanus finmarchicus and those of the Pseudocalanus and Centropages genera. Copepod abundance has been decreasing drastically with rising water temperatures, especially in the Gulf of Maine. This is the main hypothesis to explain why, for over a decade, the right whale has been gravitating toward other cold water habitats such as the St. Lawrence and why it has been visiting the Bay of Fundy, a critical habitat for the species, less and less.

This whale also seems to be changing its food preferences in favour of the copepod Calanus hyperboreus, an arctic species found in the Gulf of St. Lawrence, particularly in the Shediac Valley in the south. With changes in prey distribution and ocean conditions, right whales might venture farther north as far as the province of Newfoundland and Labrador… which are also ancestral territories of this species.

With a few exceptions, since 2015, monitoring of this species has mainly focused on the Shediac Valley. Prior to 2015, MICS had never identified any individuals in the Mingan and Sept-Îles sector. Between 2016 and 2023, 40 individuals were identified, while 27 were tallied in 2024!

Delphine Durette-Morin is a research associate at the Canadian Whale Institute (CWI), an organization responsible for monitoring North Atlantic right whales in Canadian waters. She explains that approximately 40% of the total population of this species has been seen in the Gulf of St. Lawrence in recent years. “CWI has been observing approximately the same individuals every year, including mother-calf pairs,” she points out. Hypothetically, this could mean that with each migration, right whales in the St. Lawrence transmit the location of their preferred feeding grounds to their offspring.”

The whaling of past centuries combined with the partial loss of the population may have led to a loss of culture. No longer passed on from generation to generation, this migratory route may have been forgotten over time. Are right whales rediscovering their way back to this ancestral territory through cultural learning?

Southern New England is not a new habitat for right whales. In one study, scientists report that in the 17^th century, “Early whalers hunted right whales […] off Nantucket and Martha’s Vineyard in addition to other areas off New England (Rhode Island, Connecticut, and Long Island, New York).” Use of the waters south of Nantucket also fluctuated at the time. Considered a migratory corridor, this habitat was of importance primarily in spring and winter. Right whales were also hunted in the St. Lawrence. These habitats may have been deserted as a result of this intensive whaling.

The return of right whales, whether we’re talking about lone individuals or larger groups, comes with its share of problems. The Gulf of St. Lawrence is home to a major shipping lane that is frequently used by cargo ships.

It is possible that these giants are gradually returning to well-known territories in search of food. The case of the right whales should be a lesson in understanding that the impacts of hunting can have lasting consequences. However, this cetacean is trying to adapt as best it can to the changes unfolding in its environment, which gives us hope for its future ability to recover.