Michigan Freshwater Mussel Survey Protocols and Relocation Procedures for Rivers and Streams

Freshwater mussels are an important component of the biodiversity of Michigan’s aquatic ecosystems. They have a unique ecological role in both rivers and lakes and are valuable indicators of ecosystem integrity and function (Adkinson et al. 2013). Mussels are of significant value to the health of aquatic ecosystems (Vaughn 2017). They are a food source for some fish and terrestrial animals and often comprise a significant amount of the total biomass of all benthic invertebrates (Strayer et al. 1994, Strayer 2008). The spent shells also serve as physical habitat and are often colonized by a variety of aquatic insects and other macroinvertebrates. Since they are filter feeders, they play an important role in nutrient uptake and increasing water clarity (Strayer 2017). Freshwater mussels are sensitive to declines in physical habitat and water quality; this is especially true during early life stages which are likely one of the most sensitive of aquatic organisms (Newton et al. 2008). Because mussels are generally long-lived, relatively immobile, and reliant on fish hosts for reproduction and dispersal, their community status can provide an integrative view of physical, chemical, and biological changes in a watershed.

The protocols herein are applicable to projects whose potential impacts are limited spatially to a few hundred meters of river or less (e.g. streambed disturbance, or temporarily increased sedimentation), not for projects or events impacting multiple kilometers of river (e.g. chemical or oil spills, mussel kills, or large dredging projects). Such large-scale surveys will require alternative survey designs. Recommended references include Strayer and Smith (2003), Metcalfe-Smith et al (2000), and Smith et al (2001).