2025 Final Report of Freshwater Mussel Surveys at Route 675 Crossings 1, 2, and 3 of Crystal River, Glen Arbor, Michigan
Johnson S and Knight J. 2026. 2025 Final Report of Freshwater Mussel Surveys at Route 675 Crossings 1, 2, and 3 of Crystal River, Glen Arbor, Michigan. SWCA Environmental Consultants
This report summarizes the results of all freshwater mussel work associated with Route 675 Crossings 1, 2, and 3 over the Crystal River in Glen Arbor, Michigan, including the 2025 survey and translocation efforts for freshwater mussels at Crossings 1 and 2. The Crystal River is classified as a Group 2 stream by the Michigan Natural Features Inventory and the Michigan Department of Natural Resources (MDNR), indicating that it is a river “likely to support populations of State Threatened and Endangered mussels”. In total, 990 live mussels representing five different species, were collected from the three crossing Survey Areas and relocated into suitable habitat. All mussels were identified to species, measured, and assessed for shell wear. All individuals appeared to be in good condition and healthy at the time of the survey. In 2024, SWCA relocated 111 mussels from the Crossing 3 survey area, including 106 E. dilatata and 5 L. siliquoidea. In 2025, SWCA relocated 463 mussels from the Crossing 1 survey area (E. dilatata 455, L. siliquoidea 5, S. undulatus 1, L. cardium 2, L. compressa 1) and 416 mussels from the Crossing 2 survey area (E. dilatata 360, L. siliquoidea 31, S. undulatus 16, L. cardium 8, L. compressa 1). Lasmigona compressa, a species of special concern in Michigan, was the least abundant species present, with only 2 individuals present within the survey areas, making up just 0.002% of all mussels relocated. It should be noted that several live L. compressa individuals were observed outside of the three survey areas.
- Type
- Unpublished Report
- Authors
- Johnson, Steve; Knight, Jaelynn
- Date of Issue
- 2026-02
- Publisher
- SWCA Environmental Consultants
- Units
- SLBE
- Keywords
- mussels; Crystal River
- Subjects
- Ecological Framework: Water | Water Quality | Aquatic Macroinvertebrates and Algae , Ecological Framework: Biological Integrity | Focal Species or Communities | Riparian Communities
- License
- Public Domain