August 1, 2022
Once the mussels are collected, professional ecologists teach volunteers how to safely handle and identify the species they have collected.

Citizen Scientists Focus on Freshwater Mussels

By Danelle Haake, Bruce Colravy

Photos courtesy of the authors.

Freshwater mussels are considered one of the most imperiled animal groups in the world. Of the estimated 300 species in North America, about 70 percent are extinct, endangered, threatened, or in need of conservation. In Illinois alone, 25 of the 62 extant species are listed as threatened or endangered. The Sangamon River had historically supported more than 40 species of mussels, but today just 29 remain with 25 species found in the upper portions of the Sangamon. Although they have disappeared from many lakes and streams over the last century, freshwater mussels still remain abundant in many places in Illinois.

A group of people are wading in a stream as they search for freshwater mussels. In the background are trees growing on the stream bank.
Volunteers grubbing for mussels use their hands to hunt for the animals buried in the stream bed. The cool water feels great on a summer day.

Citizen scientists (also called community scientists) with the Illinois RiverWatch Network have been monitoring mussels in their local rivers and streams for many years. Among the most active mussel volunteers are the members of the Upper Sangamon River Conservancy (USRC), who have participated annually for over a decade. Each summer, USRC volunteers have waded into the Sangamon to pluck mussels from the river bottom. By kneading their fingers through the substrate of gravel, sand, and silt where the “living rocks” make their home, the tactile senses of volunteers quickly learn to discern mussels from the river bottom. The purpose of collecting the mussels is to identify each to species and measure the size of their shells. This sort of long-term monitoring has provided important information on the diversity and health of the mussels in the Sangamon. It also allows scientists and volunteers to better understand how conditions in the river are changing. These monitoring events provide nonprofessionals the opportunity to experience these fascinating creatures first-hand, to learn about their unique life history, and, as a consequence, to become advocates for healthy rivers and streams in Illinois.

Three people measure freshwater mussels on a tabletop, and record their findings. In the background is a small group of people congregating on the pebbly shoreline of a steam.
After the mussels are identified and tagged, they are measured and weighed. The mussels are then photographed before they are released back into the river.

A year ago, USRC and Illinois RiverWatch partnered with the Illinois Natural History Survey, St. Louis Zoo, Missouri Botanical Garden, and the National Great Rivers Research & Education Center to take their citizen science to the next level. Beginning in 2021, the team committed to collecting mussels at eight locations for the next 10 years. To prevent harm to the mussels from over-sampling, four sites are visited in odd years and the other four sites are visited in even years. In addition to the normal species identification and shell measurements that are taken, volunteers for this project are tagging the mussels, taking photographs, and collecting DNA samples. By tagging the mussels, citizen scientists and researchers will know which mussels were recaptured from previous surveys. The unique identification tag along with the repeated measurements and photographs will tell the team about the growth rate, mortality, and distance of movement for the individuals, as well as providing the data needed to estimate population sizes for each location. DNA samples will be used to help researchers better understand how the populations of mussels are connected across the eight locations. These efforts are funded in part by the Living Earth Collaborative (LEC) and by the Consortium of Universities for the Advancement of Hydrologic Science, Inc. (CUAHSI).

A researcher holds a freshwater mussel with two numbered tags. The tags are small white oblongs with four numbers on each, and there is a tag on each of its shells.
The unique tag on this freshwater mussel helps researchers and community scientists to know if the mussel has been recaptured, its growth over time, mortality and distribution.

Citizen science is intended to allow people from any background to gain the knowledge and tools needed to contribute to the continued development of human understanding of the world around us. If you are interested in participating in the collection and tagging of mussels in the upper Sangamon River this August, please visit or contact Bruce Colravy at No prior experience or training is required. If you are interested in mussel monitoring but the Sangamon River is a bit far for you, the Illinois RiverWatch Network will host a training workshop for volunteers who are interested in learning how to monitor mussels in their own rivers and streams. The August 27th workshop will run from 9 a.m. to 4 p.m. and will be held at the Urban Stream Research Center in DuPage County. Attendees will be provided with background information on freshwater mussels, keys to their identification, and resources to enable them to monitor mussels on their own. Registration for this workshop is now open. Questions on this workshop can be directed to Hannah Griffis at

Danelle Haake has been the Illinois RiverWatch Director and Stream Ecologist for the National Great Rivers Research & Education Center since 2020. She began her career in biology as a citizen scientist and has continued working with citizen scientists throughout her career, including during her tenure as a Restoration Ecologist with Missouri Botanical Garden and her doctoral studies at St. Louis University.

Bruce Colravy is a founding member of the Upper Sangamon River Conservancy, established in 2009, and is the Citizen Science Coordinator for the group. He has been leading USRC mussel surveys since 2012, and has been a RiverWatch citizen science volunteer since 2009. He earned his degree in Natural Resources from Oregon State University in 2018.