Research Document - 2010/082
Information Relevant to a Recovery Potential Assessment of Lake Sturgeon: Nelson River Populations (DU3)
By H. Cleator, K.A. Martin, T.C. Pratt, and D. Macdonald
Abstract
The Lake Sturgeon (Acipenser fulvescens) was common in nearshore waters across much of Canada in the nineteenth century, but intensive fishing, habitat loss and degraded water quality caused severe reductions in population size or extirpation across their range. Today they remain extant from the North Saskatchewan River in Alberta, to Hudson Bay in the north, and eastward to the St. Lawrence River estuary. In November 2006, the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) assessed Lake Sturgeon in Canada. Designatable Unit (DU) 3, the Nelson River populations, includes Lake Sturgeon in the Nelson River in northeastern Manitoba, downstream of Lake Winnipeg (to Hudson Bay), and all related drainages. COSEWIC assessed and designated DU3 as Endangered. Historically, over-exploitation from commercial fisheries probably was the primary threat which led to depletion of Lake Sturgeon in DU3. More recently, habitat degradation or loss associated with dams/impoundments and other barriers and impacts of fishing have become the most important threats.
DU3 Lake Sturgeon is being considered for legal listing under the Species at Risk Act (SARA). In advance of making a listing decision, Fisheries and Oceans Canada (DFO) has been asked to undertake a Recovery Potential Assessment (RPA). This RPA summarizes the current understanding of the distribution, abundance and population trends of Lake Sturgeon in DU3, along with recovery targets and times. The current state of knowledge about habitat requirements, threats to both habitat and Lake Sturgeon, and measures to mitigate these impacts for DU3 are also included. This information may be used to inform both scientific and socio-economic elements of the listing decision, development of a recovery strategy and action plan, and to support decision-making with regards to the issuance of permits, agreements and related conditions, as per sections 73, 74, 75, 77 and 78 of SARA.
Six Lake Sturgeon Management Units (MUs) have been identified for DU3. Available data and expert opinion indicate that the current status of MUs 1, 4 and 5 is critical where relatively few Lake Sturgeon are known to occur. The population trajectory of MU1 is increasing, due to stocking, and unknown for MUs 4 and 5. The status of MUs 2 and 3 is deemed to be cautious with a trajectory that is stable or possibly increasing in MU2 and unknown in MU3. The status of MU6 is healthy and trajectory is unknown. Current data indicate that there are several thousand adult Lake Sturgeon in DU3. The long-term recovery goal is to protect and maintain healthy, viable populations of Lake Sturgeon in all MUs.
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