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Recovery Strategy for the Shortnose Cisco (Coregonus reighardi) in Canada

5. Critical habitat

5.1 Identification of the species’ critical habitat

Under the Species at Risk Act (SARA), habitat for aquatic species is defined as:

“…spawning grounds and nursery, rearing, food supply, migration and any other areas on which aquatic species depend directly or indirectly in order to carry out their life processes, or areas where aquatic species formerly occurred and have the potential to be introduced” [s.2(1) SARA]

Critical habitat under SARA is defined as”

“… the habitat that is necessary for the survival or recovery of a listed wildlife species and that is identified as the species’ critical habitat in the recovery strategy or action plan for the species” [s.2(1) SARA]

Little is known about the habitat requirements of the Shortnose Cisco other than that the species occupied moderately deep waters of lakes Ontario (22m to 92m), Michigan (37m to 110m) and Huron (37 m to 92 m) (Committee on the Status of Endangered Wildlife in Canada (COSEWIC) 2005). Based on its diet, it must have occurred where it was able to feed on the freshwater crustaceans Mysis diluviana and Diporiea spp. (Parker 1988, COSEWIC 2005). Naumann and Crawford (2009) found that the identification of critical habitat for rare and taxonomically uncertain fish species, such as the closely related Shortjaw Cisco in Lake Huron, was not feasible due to rarity of occurrence and the need to consider other important physical and biological habitat factors other than water depth alone. The lack of species-specific information on the biology and life history requirements of the Shortnose Cisco would of itself preclude the identification of critical habitat at this time. Furthermore, the presumed extinction of the Shortnose Cisco suggests that the survival or recovery of the species is not possible and, consequently, critical habitat, as defined by SARA, is not an applicable concept.