Improving propagation techniques for freshwater mussels
Juvenile Higgins' eye pearlymussel growing within mobile rearing unit. Bright ring along each mussels’ edge shows growth from this year. USFWS photo.
Freshwater mussels are considered key indicators of water quality and contribute to healthy aquatic ecosystems. However, steep population declines due to habitat degradation and pollution, changing agricultural practices, invasive species and impacts of climate change, have presented conservation professionals with challenges to continued conservation of rare and endangered mussels.
The U.S. Fish and Wildlife Service’s Genoa National Fish Hatchery, which safeguards and propagates freshwater mussels for reintroduction into native habitat, is utilizing advanced technology in mobile rearing to evaluate how different water sources support growth and survival of young freshwater mussels. The Eastern Tallgrass Prairie and Big Rivers Landscape Conservation Cooperative (LCC) has dedicated funding to this project to help assess propagation techniques in light of broad-scale stressors to our aquatic resources.
"The Eastern Tallgrass Prairie and Big Rivers LCC is very pleased to be able assist with funding for the mussel research project," said LCC Coordinator Glen Salmon. "The tremendous network of big rivers, smaller tributaries, streams and headwater creeks form the very lifeblood across the geography of the regions this partnership covers. Freshwater mussels are an important component of Midwestern river systems and this project will increase our knowledge about possible reintroduction techniques."
A mobile aquatic rearing station, or MARS, was deployed along the banks of the Mississippi River at the U.S Army Corps of Engineers’ Blackhawk Park near De Soto, Wis., in the summer of 2012 to raise rare and endangered mussel species, including Higgins’ eye pearlymussel, hickorynut, black sandshell and snuffbox. Freshwater mussels like these are known as ecological engineers for their unique ability to siphon phytoplankton, bacteria and fungi from the water column and deposit nutrients into the sediment that feeds other aquatic life.
"This project is a great example of how our national fish hatcheries continue to integrate science into their work and remain an important component in the recovery of aquatic species," said Kurt Schilling, the Service’s Midwest Region Hatchery Program Supervisor.
The mobile rearing unit is placed near the Mississippi River, and filters large debris from river water while incubating the juvenile mussels. The research will help biologists determine the differences in growth success of mussels in river water as compared to propagation in a hatchery environment, and ultimately optimize rearing techniques in light of expanding natural resource stressors to increase early life stage survival of these ecologically-essential freshwater animals.
The MARS unit was deployed in June 2012 and will remain along the banks of the Mississippi River through the summer to incubate and grow freshwater mussels using river water. The research will help inform propagation techniques for freshwater mussels, which are vitally important to clean and healthy aquatic ecosystems. USFWS Photo.