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Research Document - 2013/061

Recovery potential modelling of Rocky Mountain Sculpin (Cottus sp.), Eastslope populations, in Alberta

By J.A.M. Young and M.A. Koops


The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) had assessed the Rocky Mountain Sculpin (Cottus sp.) as Threatened in Canada (COSEWIC 2005). 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 Rocky Mountain Sculpin populations are particularly sensitive to perturbations that affect survival of immature individuals (from hatch to age 2), and to the collective survival of adults (ages 2-8).  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 1480 adult Rocky Mountain Sculpin, requiring 0.12 ha of suitable habitat. Current vital rate and abundance estimates suggest that the population may be in decline, with an expected time to extinction of ~75 years. Recovery strategies which incorporate improvements in the most sensitive vital rates of the Rocky Mountain Sculpin are most likely to improve the population growth rate; improvements of 10% in survival of all life stages significantly delayed extinction risks, and improvements of 20% had a stabilizing effect on the population.

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