Research Document - 2010/073

Recovery Potential Modelling of Wavy-rayed Lampmussel (Lampsilis fasciola) in Canada

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

Abstract

The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) had assessed the Wavy-rayed Lampmussel (Lampsilis fasciola) as Endangered in Canada; in 2010 the Wavy-rayed Lampmussel was re-assessed as Special Concern. Here we present population modelling of two populations 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 Wavy-rayed Lampmussel populations are particularly sensitive to perturbations that affect survival of adult mussels, and potentially sensitive to survival at the larval (glochidia) and early juvenile stage. Harm to these portions of the Wavy-rayed Lampmussel 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 abundance recovery targets of at least 1500 adult female mussels. In the absence of mitigating efforts or additional harm, we estimate that it will take a growing Wavy-rayed Lampmussel population up to 60 years to reach this recovery target. However, by affecting at least a 10% increase in survival rates, recovery strategies such as habitat rehabilitation or enhancement can reduce the recovery time of a heavily impacted population by more than half.

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