Research Document 2021/027

Information in support of a Recovery Potential Assessment of Pygmy Whitefish (Prosopium coulterii), Great Lakes–Upper St. Lawrence population (DU 5)

By Andrews, D.W., van der Lee, A.S., Pratt, T.C., and Drake, D.A.R.

Abstract

Pygmy Whitefish (Prosopium coulterii) was first captured in Lake Superior in 1952. In November 2016, COSEWIC assessed Pygmy Whitefish, Great Lakes–Upper St. Lawrence populations (DU5) as Threatened. The reason given for this designation was that “this small-bodied freshwater fish has experienced dramatic declines in abundance over the last several decades, with an overall estimated decline of 48% since 2000. The continued presence of invasive fishes and recovery of native predatory fishes may threaten or limit recovery, respectively” (COSEWIC 2016). The Recovery Potential Assessment (RPA) provides background information and scientific advice needed to fulfill various requirements of the federal Species at Risk Act. This research document provides the current state of knowledge of the species including its biology, distribution, population trends, habitat requirements, and threats, which will be used to inform recovery plans. A population status assessment indicated that the density of Pygmy Whitefish in Lake Superior has declined since 2013. A threat assessment indicated that the greatest threats to Pygmy Whitefish within DU5 are climate change, invasive species, and pollution; however, the impact of these threats is currently unknown. Predation from top predators such as Lake Trout (Salvelinus namaycush) and Burbot (Lota lota) may be limiting population growth.

Research Document 2021/027 (PDF, 1,931 KB)

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