Information à l'appui d'une évaluation du potentiel de rétablissement de la lamproie du Nord (Ichthyomyzon fossor) – populations de la rivière Saskatchewan et du fleuve Nelson

Abstract

Northern Brook Lamprey is a small, non-parasitic lamprey species, and is one of three species of the genus Ichthyomyzon found in Canada. Northern Brook Lamprey and the parasitic Silver Lamprey are a closely related species pair. Northern Brook Lamprey is at the northern edge of its range in Canada, is distributed in Ontario in the tributaries of the Laurentian Great Lakes, tributaries of the St. Lawrence River in Ontario and Quebec, and Manitoba in the Whitemouth River and upstream, including its tributary the Birch River. In November 2020, the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) assessed the Great Lakes-Upper St. Lawrence populations (DU1) as Special Concern and the Saskatchewan-Nelson River populations (DU 2) were designated Endangered. The Saskatchewan-Nelson River populations have a limited distribution, a decline in the number of mature individuals based on observed reductions in extent of occurrence, area of occupancy, and number of locations, and an inferred decline in quantity and quality of aquatic habitat. The most serious threats to which populations are exposed are decreases in stream flows under current and future climates, and anticipated increases in water temperature. Northern Brook Lamprey, Saskatchewan-Nelson River populations are currently not listed under Schedule 1 of the Species at Risk Act (SARA), while the Great Lakes-Upper St. Lawrence populations are listed as Special Concern. The Recovery Potential Assessment (RPA) provides information and scientific advice needed to inform the listing decision and various requirements of SARA for the Saskatchewan-Nelson River populations including permitting activities that would otherwise violate SARA prohibitions and the development of recovery strategies and action plans. This Research Document describes the current state of knowledge on the biology, ecology, distribution, population trends, habitat requirements, and threats of Northern Brook Lamprey. Mitigation measures and alternative activities related to the identified threats that can be used to protect the species are also presented.