The Gulf of St. Lawrence is a large inland sea of 250,000 km2 bordered by Quebec, Newfoundland, New Brunswick and Nova Scotia. Between 1995 and 2005, 32 different right whales (approximately 10% of the known population) were photographed by whale watch naturalists, but otherwise little is known about the presence of right whales in the region. More than 25 years of photo-identification research has shown that not all right whales use the Grand Manan Basin and Roseway Basin Conservation Areas in the summer and fall, but other habitat areas have yet to be identified. The Gulf of St. Lawrence is potentially an important right whale habitat area since mother and calf pairs have been sighted there in the summer months. At the moment, there is only one recognized nursery ground in Canadian waters, located in the Grand Manan Basin Conservation Area. However, several of the mothers frequenting the Gulf of St. Lawrence do not bring their calves to the Bay of Fundy and even their daughters do not use the Bay of Fundy. Therefore, there is speculation as to whether mothers may pass on their preferences for summer and fall habitat areas to their offspring.

In the Gulf of St. Lawrence, right whales are mostly seen in the waters south of Gaspé Peninsula at the mouth of Chaleur Bay. Right whales are occasionally observed north of Anticosti Island and near Tadoussac up the St. Lawrence River.
Most of the right whales sighted in the Gulf of St. Lawrence are referred to as "irregular" or "offshore" whales, a term used to describe a class of right whales that behave differently than the majority of the catalogued population such as those that migrate between Florida and the Bay of Fundy. Offshore whales are mostly seen in habitat areas further from the coast and there are often large gaps in their sighting records.

Crabscar is a male first seen in 1981 in the Great South Channel and he has a rather interesting sighting history similar to those whales seen in the Gulf of St. Lawrence and characteristic of the sighting history of "offshore" whales. After he was initially identified, he was spotted every two or three years along the east coast of Canada or the United States until 1994 when he disappeared for 8 years. After 2002, he has only been reported in the Great South Channel and the Gulf of St. Lawrence.

Crabscar along the coast of the Gaspé Peninsula in the Gulf of St. Lawrence in 2006.
Most of the reported right whale sightings in the Gulf of St. Lawrence occur at the mouth of Chaleur Bay and along the southern coast of the Gaspé Peninsula. Few right whale surveys have been conducted in this region. In 2006, the Canadian Whale Institute and the Centre d’Études et de Protection de la Baleine Noire du Saint-Laurent initiated the organization of a network of local observers. Utilizing local mariners in collecting opportunistic right whale sightings, this network will contribute to our understanding of the importance of the Gaspé Peninsula habitat area to the recovery of the North Atlantic right whale.