River Raisin Mussel Survey

ASTI Environmental conducted a full suite of native freshwater mussel services, including a transect-based semi-quantitative survey, salvage and relocation, and post-relocation monitoring in the River Raisin at the Sharon Valley Road (east crossing) in Sharon Township, Washtenaw County, Michigan. The work was completed in advance of bridge construction activities due to the presence of state-listed mussels and resulted in the successful relocation of 248 live mussels representing seven species. Relocated specimens included 97 state-threatened purple wartyback (Cyclonaias tuberculata), two state-threatened wavy-rayed lampmussel (Lampsilis fasciola), and more than 50 individuals classified as special concern.

Following initial surveys and relocation planning, ASTI Environmental performed mussel salvage and relocation activities within an approximately 710 m² survey area. All live native mussels were safely transported to an MDNR-approved upstream relocation area. Tasks included mussel species identification, tagging and documentation, habitat assessment, and relocation. Compliance with the Michigan Freshwater Mussel Survey Protocols and Relocation Procedures was maintained throughout all phases of the project. Post-relocation monitoring was conducted to evaluate transplant success, with monitoring efforts continuing as required by MDNR.

A high density of threatened and endangered mussels was documented within the survey area, with 99 live individuals (40% of mussels collected) requiring PIT tagging, processing, relocation, and monitoring. Tagging methods were adjusted, while maintaining adherence to Michigan protocol guidance, to reduce overall labor demands without compromising compliance.