Marion Wells, one of CMT’s senior ecologists, holds a Pink Heelsplitter (Potamilus alatus) and Fatmucket (Lampsilis siliquoidea) mussel located in Huron, Indiana

Nearly three-quarters of North America’s native freshwater mussel species are considered endangered, threatened, or species of special concern. Invasive species, including non-native mussels such as the zebra mussel, can also threaten native species.

As natural filter feeders, freshwater mussels strain out pollutants from the water and help improve its quality. The disappearance of freshwater mussels in an area usually indicates chronic water pollution problems.

The U.S. Fish and Wildlife Service (USFWS) protects federally protected mussels, and their habitats and impacts should be avoided and minimized to the maximum extent practicable. Many bridge, pipeline, and road rehabilitation projects that include stream or river crossings, in-stream work, bank stabilization, discharge outfalls, or dam removal require freshwater mussel surveys. If impacts cannot be avoided, all streams which contain mussels or potential mussel habitat must be surveyed prior to any proposed stream disturbance to determine the presence, or probable absence, of federally listed mussel species (FLS).

CMT has extensive experience performing mussel surveys for federal, state, and local transportation projects.

Our work typically involves:

  • Mussel habitat delineations
  • Qualitative surveys to determine the presence or absence of native mussels
  • Quantitative surveys to determine mussel diversity and density
  • Mussel salvage and translocations
  • GPS/GIS and ArcPad technology for accurate mapping and monitoring

We have ecologists on staff that are approved mussel surveyors who complete mussel surveys throughout the Midwest. Marion Wells, one of our senior ecologists, has a federal permit to survey, relocate and handle federally-listed threatened or endangered mussel species – a certification only held by a small number of individuals across the country. She is certified to conduct federally-listed threatened and endangered mussel species surveys and relocations in all watersheds throughout the states of Ohio and Missouri. She is also qualified and has conducted mussel surveys in Illinois and Indiana for state-listed species.

Our experience with regional regulations and regulators ensures compliance with all project specifications. To ensure you comply with required protocols, we advise that you begin consultation early to avoid construction delays. Mussel surveys may only be conducted from May 1st to October 1st.

Need help with your project? For more information please contact Heather Lacey, Environmental Group Manager (937-701-6578;

Fatmucket (Lampsilis siliquoidea) mussel located in Marysville, Ohio