The Freshwater Mussel Mission Continues on the Little Miami State and National Scenic River
Over the past three decades the freshwater mussel population of the Little Miami State and National Scenic River has declined. Freshwater mussels are a vital part to providing and maintaining a healthy river by providing filtration for the waters of the Little Miami, and in turn supporting a healthy river for fish and wildlife. Currently, there are about 36 species of freshwater mussels calling the Little Miami home. However, based on recent surveys along the Little Miami River and its major tributaries, freshwater mussel numbers and species have continued to decrease dramatically.
The mission is two-fold
1) Support efforts to seek and identify suitable places on the Little Miami River - in terms of habitat and fish species
2) Help develop a strategy and plan to reintroduce propagated freshwater mussels into the Little Miami River where they once thrived.
Freshwater Mussel Restoration and Silo Deployment Efforts in 2022
The freshwater mussel conservation project that began in 2021 continues into 2022. The project continues joint efforts between the U.S. Forest Service (USFS) and LMC to support conservation initiatives on the Little Miami State and National Scenic River. This year's activities are occurring on two of Ohio's State and National Scenic Rivers – The Little Miami and Big Darby Creek. The program goal is to identify fish species and suitable habitat where freshwater mussels could be reintroduced to support mussel conservation and restoration efforts.
Working with Wendell Haag, Ph.D. Research Biologist, U.S. Forest Service Collaborating Scientist, Monte McGregor, Ph.D., Director of the Center for Conservation of Mollusks in Frankfort, Kentucky, and Michael A. Hoggarth Ph.D., professor and chair of the Department of Life and Earth Sciences at Otterbein University and Associate Curator of the Museum of Biological Diversity at The Ohio State University. Dr. Hoggarth also co-authored the book, The Freshwater Mussels of Ohio, Ohio State University Press, with Thomas A. Watters Ph.D. and David H. Stansbery Ph.D. The Little Miami Conservancy has constructed 42 concrete freshwater mussel silos, camouflage-painted, that have now been deployed in the Little Miami River, and other selected streams in the region.
The Big Day Arrives - The Mussels Have Landed!
LMC’s commitment to the vision of restoring freshwater mussels to the Little Miami State and National River has taken another step forward. A yearlong project that has involved a collaboration with some of the nation’s foremost freshwater mollusk (mussel) experts and a team of dedicated Little Miami Conservancy volunteers is progressing at a brisk pace.
A key part of this journey continued over three days - July 11 - 13, with the deployment of 29 concrete silos containing 580 juvenile freshwater mussels along 74 miles of the Little Miami River by 11 volunteers. This was a watershed moment for this project, as it represents the culmination of hours of work researching best practices in freshwater mussel silo design and construction, collaboration with experts on freshwater mussel growth and development, logistics of silo deployment, use of environmental DNA (eDNA) analysis to determine presence of fish species, and so many other decisions.
The Process: Live Juvenile Freshwater Mussel Transport from Frankfort
Beginning early July 11, an LMC crew made the trip to the Kentucky Department of Fish and Wildlife Resources Center for Mollusk Conservation in Frankfort, KY to collect propagated juvenile freshwater mussels. As with any wildlife transition, the key to juvenile mussel survival is to make their habitat transition seamless from the lab into the river. At the lab in Frankfort, staff loaded 580 infant mussels – meticulously counted out into the 29 silo inserts – and kept comfortable in coolers containing hatchery water and fitted with air bubblers providing abundant dissolved oxygen for the three hour journey north.
While the process seems simple at first, freshwater mussels are fragile creatures relying on fish partners for food, water, and appropriate habitats. LMC volunteers went all out to make the journey safe and successful, by monitoring water temperature with stream thermometers, and providing continuous bubblers, in specially modified tailgate type picnic coolers.
The First Deployments
That same day, LMC volunteers drove from Frankfort to 3 sites on the Upper Little Miami River to begin the deployments. The sites along the Little Miami were selected and scouted beforehand taking into account 30 years of previous Little Miami River freshwater mussel research by Dr. Hoggarth, recent scouting by volunteers of depth, flow, substrate, and eDNA analysis of fish species, as well as river flow and current weather conditions. The goal was to select accessible deployment sites with a mixed riverbed substrates including gravels and cobble rocks without fine sediments. Freshwater mussels require a silt-free stream bed, where they can burrow into sand, gravel, and cobble substrates, hidden from predators. There, the freshwater mussels filter nourishment from moving water, and attract suitable host fish needed for natural propagation, and to protect and nourish them during their larval stage of development.
For this stage of the project, the juvenile freshwater mussels remain protected in their silos for three months. Hopefully during this time, the juveniles will grow and develop in protected environment with sufficient river flow, depth and dissolved oxygen to indicate whether the deployment site is indicative of a suitable site for restoration and protection.
Once at the site, the crew took water temperature readings and gradually mixed the stream water with hatchery water from Frankfurt in the coolers, to be sure the hatchery water and the river water was tempered to within about one degree, in order to acclimate the freshwater mussels. In addition, a thermo-logger tag/button was inserted into one silo at each site. These tags are synchronized into a computer program to log water temperature every ninety minutes. At this point, 2-3 silos were placed at each site on the riverbed. Visual markers were placed using landmark photography, GPS coordinates, and distance from the riverbank. This step is critical, as it will help LMC volunteers locate the mussel silos in ninety days when it is time to retrieve them for further study.
The Freshwater Mussel Deployment Mission was Completed Over Three Days
The rest of the freshwater mussel silos were deployed over the next two days, covering 8 spots along the Middle and Lower Little Miami. This journey could not have been completed without the cooperation and support of volunteer crew that made it happen. Everyone plays a part in a project that contained so many variables and “what ifs” including weather which supported us with appropriate river levels to allow this to happen safely.
What’s Ahead for These Freshwater Mussels?
Now - we wait. The goal of this project has always been understanding suitable freshwater mussel habitats and to determine suitable sites for restoring declining populations. The goal is to see if the juvenile freshwater mussels, deployed when they were smaller than grains of rice, can survive and grow in the next three months. The silos will be collected in September to measure the survivorship and growth of the juvenile freshwater mussels.
Our Thanks and Acknowledgement
This project could only be completed with the help of many experts and volunteers who have given generously their time and knowledge. Much credit goes out to the experts for their generous consultation, published knowledge, and passion for this research.
Among them are Monte McGregor, Ph.D, and the Center for Conservation of Mollusks in Frankfort, Kentucky; Wendell Haag, Ph.D, U.S. Forest Service; Michael Hoggarth, Ph.D, Otterbein University, Trisha Gibson, Ohio State University Freshwater Mussel Conservation and Research Center, Columbus, Ohio; Chris Lorentz, Ph.D, Thomas More University Biology Field Station; Chris Barnhart, Ph.D Missouri State University; Michael Miller, Ph.D. and Michael Booth, Ph.D, University of Cincinnati.
Encouragement and support was also provided by the Ohio Department of Natural Resources.