Assessing the Use of Translocation as a Tool to Prevent the Extirpation of a Population of Yellow Lampmussel (Lampsilis cariosa) in Nova Scotia

Abstract

Yellow Lampmussel (Lampsilis cariosa; Say, 1817) is a freshwater mussel listed as Threatened in Nova Scotia and Special Concern federally. It is found in three watersheds in Nova Scotia, with the largest population in Blacketts Lake at ~988,000 mussels. Chain Pickerel (Esox niger; Lesueur, 1818) was illegally introduced into Blacketts Lake in 2010, resulting in a drastic reduction in White Perch (Morone americana; Gmelin, 1789), the obligate fish host of the Nova Scotia Yellow Lampmussel. This freshwater mussel cannot complete its lifecycle without White Perch. Density and age demographics of Yellow Lampmussel in Blacketts Lake were estimated by quadrat sampling to assess the impact of Chain Pickerel and examine the need of translocation to prevent the extirpation of this at-risk population. I carried out a pilot translocation within Blacketts Lake, and developed criteria to identify and assess potential recipient lakes for translocated mussels based on habitat suitability and fish host availability. The average mussel density in Blacketts Lake was 1.9(±0.45SE)/m2. The oldest age class was 20 years and the youngest was 7, indicating no recent recruitment has occurred within the last 7 years. Mussels responded well to being moved within the lake with all burrowing in sediment and resuming normal activity within 24 hours; no mortality occurred. Of 117 Cape Breton lakes assessed only nine had conditions suitable to support Yellow Lampmussel. While there are few suitable recipient lakes, translocation may still be the best hope for preventing the extirpation of the Blacketts Lake Yellow Lampmussel population. However, ecological risks associated with translocation must be carefully considered before moving forward.