Have Whales Ever Gotten Trapped by the Ice in the St. Lawrence Estuary?

By François Vachon

To date, no such incident has ever been recorded within the boundaries of the St. Lawrence Estuary.

The Estuary extends from Île d’Orléans, where the fresh water of the St. Lawrence River and the salt water of the ocean mix, to Pointe-des-Monts, where the river widens to form an inland sea. In some parts of the Estuary, including Tadoussac, rising warm water causes an absence of ice known as a polynya. According to Guillaume Lelièvre Saint-Pierre, captain of the F.-A. Gauthier, the ferry that shuttles between Matane, Baie-Comeau and Godbout, overall, ice is also quite thin in the middle of the river and can easily be broken.

Whales generally avoid areas that are completely frozen over since they must come to the surface in order to breathe. However, some species remain in partially ice-covered environments to take advantage of abundant food resources, despite the risk of perishing. This is why we have been able to observe large rorquals in recent weeks in Les Escoumins and Godbout.

In the Gulf of St. Lawrence, however, numerous cases of whales trapped in the ice have been documented. In fact, between 1868 and 1992, approximately 40 individuals found themselves caught in the ice off the southeastern coast of Newfoundland, an area that whale scientists call a trap for marine mammals. In 70% of the cases, the incidents were fatal for the animals. According to Jack Lawson, a researcher with Fisheries and Oceans Canada, winds are responsible for creating these whale traps. First, winds disperse the ice, which allows whales to move and feed; however, when the winds shift direction, huge chunks of ice can join together and trap cetaceans, even blocking their access to oxygen.

Additionally, Arctic species such as belugas and narwhals appear to prefer to spend most of the winter in ice-covered waters. They use the ice cover to protect themselves from predators and rough seas. The risk of entrapment in the ice remains, however, and a number of individuals are believed to perish this way every year in the Arctic.