Species Profile

Atlantic Salmon Lake Ontario population

Scientific Name: Salmo salar
Taxonomy Group: Fishes
Range: Ontario, Atlantic Ocean
Last COSEWIC Assessment: November 2010
Last COSEWIC Designation: Extinct
SARA Status: No schedule, No Status

Individuals of this species may be protected under Schedule 1 under another name; for more information see Schedule 1, the A-Z Species List, or if applicable, the Related Species table below.

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Image of Atlantic Salmon

Atlantic Salmon Photo 1



There has been no record of this population since 1898. Human settlement was the most significant factor leading to the demise of the Lake Ontario population of Atlantic Salmon. Activities such as land clearing for timber and agriculture degraded and destroyed habitat by altering water levels and adversely impacting water quality through increased erosion and siltation. Further, the construction of mill and driving dams for the timber trade prohibited fish passage, and congregating fish at the base of the dams were overexploited by fishers. A short-lived commercial fishery also contributed to the loss of this population of Atlantic Salmon.




PLEASE NOTE: Not all COSEWIC reports are currently available on the SARA Public Registry. Most of the reports not yet available are status reports for species assessed by COSEWIC prior to May 2002. Other COSEWIC reports not yet available may include those species assessed as Extinct, Data Deficient or Not at Risk. In the meantime, they are available on request from the COSEWIC Secretariat.

8 record(s) found.

COSEWIC Status Reports

  • COSEWIC assessment and status report on the Atlantic Salmon Salmo salar (Lake Ontario population) in Canada (2006)

    The Atlantic salmon (Salmo salar) belongs to the family Salmonidae that includes Atlantic and Pacific salmon, trout, charr, grayling and whitefishes. Adult Atlantic salmon that have been out to sea have trout-like bodies with a blue-green back and silvery sides. The freshwater adults once populating Lake Ontario were reportedly smaller and darker than anadromous strains. This report is concerned with the Lake Ontario population (COSEWIC Designatable Unit).
  • COSEWIC Assessment and Status Report on the Atlantic Salmon Salmo salar in Canada (2015)

    The Atlantic Salmon (Salmo salar) is a member of the family Salmonidae. This species has a fusiform body shape and matures at sizes ranging from 10 to 100+ cm. Atlantic Salmon exhibit plastic life histories and may have multiple reproductive and migratory phenotypes within a population, including freshwater resident and oceanic migrant forms. All phenotypes reproduce in fresh water. The oceanic migrant (anadromous) form is the best known phenotype, and with the exception of the extinct Lake Ontario population, is the only form considered in this report. Juveniles spend 1-8 years in fresh water, then migrate to the North Atlantic for 1-4 years, and then return to fresh water to reproduce. Demographically functional units tend to be at the watershed scale, but population subdivision may occur within watersheds. The Canadian range of this species was subdivided into 16 designatable units (DUs) based on genetic data and broad patterns in life history variation, environmental variables, and geographic separation.

COSEWIC Assessments

Response Statements

  • Response Statement - Atlantic Salmon, Lake Ontario population (2011)

    Once a prolific resident throughout the Lake Ontario watershed, there has been no record of this population since 1898. The Lake Ontario population was extinguished through habitat destruction and through over-exploitation by food and commercial fisheries. As the original strain is gone, re-introduction is not possible. Recent attempts to introduce other strains of the species have resulted in some natural reproduction, but no evidence of self-sustaining populations.   
  • Response Statements - Atlantic Salmon (2006)

    Once a prolific species throughout the Lake Ontario watershed, there has been no record of a wild Atlantic salmon since 1898. The Lake Ontario Atlantic salmon was extinguished through habitat destruction and through over-exploitation by a food and commercial fishery. Attempts to re-establish Atlantic salmon through stocking have failed, and the original strain is no longer available. 

COSEWIC Annual Reports

  • COSEWIC Annual Report - 2006 (2006)

    2006 Annual Report to the The Minister of the Environment and the Canadian Endangered Species Conservation Council (CESCC) from the Committee on the Status of Endangered Wildlife in Canada.
  • COSEWIC Annual Report - 2010 - 2011 (2011)

    Under Canada’s Species at Risk Act (SARA), the foremost function of COSEWIC is to “assess the status of each wildlife species considered by COSEWIC to be at risk and, as part of the assessment, identify existing and potential threats to the species”. COSEWIC held two Wildlife Species Assessment Meetings during the past year assessing the status or reviewing the classification of a total of 92 wildlife species.

Consultation Documents