Freshwater mussels are valuable components of healthy ecosystems. They are dependent on good water quality and physical habitat conditions, as well as an environment that will support populations of host fish. As filter feeders, mussels clean the water by removing a variety of materials from the water column, such as suspended sediment, organic matter, bacteria, and phytoplankton. Mussels filter particles from the water and digest useful particles as food or bind non-digestible particles in mucus and deposit them on the substrate where they are available to other benthic life forms.
Historically, mussels were harvested in Iowa in the 19th and 20th Centuries for freshwater pearls, the button industry, and, most recently, for the cultured pearl industry. Over- harvesting due to these activities seriously depleted the mussel populations in Iowa. In the early 20th Century, as harvesting was declining, other threats to mussel populations emerged, including habitat alteration and water pollution. Destruction of mussel habitat has ranged from the obvious—dams, dredging, and channelization—to the more subtle—siltation and contamination.
Previous mussel surveys show that there have been dramatic declines in mussel species. Historically, there were 55 species of freshwater mussels in Iowa. Now some species are gone from Iowa completely and some are only found in the Mississippi River.
For something that looks like a living rock, they have a unique life cycle and interesting adaptations to the environment in which they live. Come learn more!
Jen Kurth is a Natural Resources Biologist in the Water Quality Improvement Section of the Iowa DNR where she coordinates the monitoring for the Section 319 watershed projects. She grew up in southeastern Minnesota and has a B.A in Theatre—set design and scenic art and a B.S. in Biology from the University of Minnesota and a M.S. in Ecology and Environmental Science from the University of Maine. Her area of expertise is freshwater mussels. She has worked on everything from fish host studies for several species of mussels, surveys to determine distributions and densities of mussels, translocations of mussels, and developing new methods for tagging and recapturing mussels using Passive Integrated Transponder (PIT) tags, as well as a statewide freshwater mussel survey effort for Iowa and the development of an index of biotic integrity for Iowa mussels.
Jennifer Kurth