Research Document - 2011/049
Recovery Potential Modelling of Lake Chubsucker (Erimyzon sucetta) in Canada
By J.A.M. Young and M.A. Koops
The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) had assessed the Lake Chubsucker (Erimyzon sucetta) as Endangered in Canada (2008). Here we present population modelling to assess allowable harm, determine population-based recovery targets, and conduct long-term projections of population recovery in support of a recovery potential assessment (RPA). Our analyses demonstrated that the dynamics of Lake Chubsucker populations are particularly sensitive to perturbations that affect survival of immature individuals (from hatch to age 2), and are more sensitive to survival and fecundity of new spawners than of older adults. Harm to these portions of the life cycle should be minimized to avoid jeopardizing the survival and future recovery of Canadian populations. Based on an objective of demographic sustainability (i.e., a self-sustaining population over the long term), we propose a population abundance recovery target of at least 2700 adult Lake Chubsucker, requiring 1 km² of suitable habitat. In the absence of mitigating efforts, additional harm or habitat limitations, we estimate that a growing Lake Chubsucker population will take approximately 12 years to reach this recovery target if starting from a population of 270 adults. Recovery strategies which incorporate improvements in the most sensitive Lake Chubsucker vital rates will have the greatest effect on population growth.
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