SESSION C:

Title: Methods for Relocation of Freshwater Mussels Threatened by Habitat Alteration (Dam Removal) on the Sebasticook River

Authors: Jennifer Kurth (student)¹, Cynthia Loftin², and Judith Rhymer^1
1Department of Wildlife Ecology, 5755 Nutting Hall, University of Maine, Orono, ME. Jennifer_Kurth@umit.maine.edu. 207-581-1340. Judith_Rhymer@umit.maine.edu, 207-581-2863.
²USGS Maine Cooperative Fish and Wildlife Research Unit, 5755 Nutting Hall, University of Maine, Orono, ME. Cyndy_Loftin@umenfa.maine.edu. 207-581-2843.

Abstract:

Relocation of mussels from areas where habitat alterations are proposed can be an important conservation tool. The pending removal of the Fort Halifax dam on the Sebasticook River in Maine would potentially result in extensive mortality of two state-listed threatened species of mussels, the Yellow Lampmussel (Lampsilis cariosa) and the Tidewater Mucket (Leptodea ochracea) that occur in the impoundment above the dam. Our study assessed populations of these two species in the impoundment, and determined the effects of within- and between-waterbody relocations on survival. We conducted a qualitative survey of the Fort Halifax dam impoundment to determine locations of these two species and a quantitative survey near the upper end of the impoundment where the greatest numbers of these species occur. Estimated densities in survey plots were 0.05-1.1/m² for Yellow Lampmussels and 0.0-0.41/m² for Tidewater Muckets. In a 2004 pilot study, we relocated a co-occurring common species, the Eastern Lampmussel (Lampsilis radiata radiata), within the impoundment and to two other sites in the watershed, Unity Pond and Sandy Stream. Recapture rates in 2005 were 25-74.4%, with only one confirmed death (in the control group), suggesting that relocation between waterbodies may be a feasible method of conserving freshwater mussels. Based on these results, we repeated the experiment in 2005 with Yellow Lampmussels and Tidewater Muckets. As part of this effort, we used Passive Integrated Transponder (PIT) tags to track relocated mussels to assess the feasibility of this monitoring tool.