The Beluga whale critical habitat, which includes the Upper Estuary, the Saguenay River up to Sainte-Marguerite Bay, and the southern channel of the Lower Estuary, supports the vital functions of calving and rearing of the young. Due to the lack of information, studies are planned in the near future to increase knowledge of the species. Critical habitat actual limitations could change someday. Purpose The beluga (Delphinapterus leucas) population in the St. Lawrence Estuary was greatly reduced by hunting, which was finally banned in the St. Lawrence in 1979. In May 2005, this beluga population was officially listed as a threatened species on SARA’s List of Wildlife Species at Risk. Additional Information St. Lawrence beluga critical habitat is identified using the best available information. All the available information on its prey, seasonal distribution, use and characteristics of its habitat has been reviewed by Mosnier (2010). This literature review was used to produce a science advisory report reviewed by marine mammal experts. Beluga whale critical habitat has been identified with the information and the scientific advice, using the area of occupancy approach and corresponds to the summer distribution of groups made up of adults and new-born calves and juveniles. Mosnier, A., Lesage, V., Gosselin, J.-F., Lemieux Lefebvre, S., Hammill, M. O., Doniol-Valcroze, T. 2010. Information relevant to the documentation of habitat use by St. Lawrence beluga (Delphinapterus leucas), and quantification of habitat quality. DFO Can. Sci. Advis. Sec., Res. Doc. 2009/098. iv + 35 p. DFO. 2012. Recovery Strategy for the beluga whale (Delphinapterus leucas) St. Lawrence Estuary population in Canada. Species at Risk Act Recovery Strategy Series. Fisheries and Oceans Canada, Ottawa. 88 pp + X pp.