The last warm months of the summer growing season are always busy at Genoa NFH. The mussel program manages culture systems in numerous locations, and at the end of the summer we start the process of cleaning, collecting, counting and measuring the juveniles from these systems. These culture locations have allowed juvenile mussels to eat and be exposed to a diverse, natural food base in secure locations (Dubuque’s Ice Harbor, in partnership with the National Mississippi River Museum and Aquarium, and Blackhawk Park, in partnership with the US Army Corps of Engineers), but are not as easily managed in freezing winter temperatures. So, juvenile mussels are brought back to the Mussel Culture building at the hatchery where they will spend the winter inside in flow through pans, circular tanks, and raceways. The pond water flowing through these pans, tanks, and raceways will be near freezing, but we can make sure pipes and valves don’t freeze and compromise water flow, and that the juvenile mussels are safe all winter.

Juvenile Higgin’s Eye going in to tanks in the MARS culture trailer early in the summer. Photo credit: MeganBradley/USFWS.

For the 2023 growing season, thousands of new juveniles and larger sub-adults were housed in the Mobile Aquatic Rearing System (MARS trailer) at Blackhawk Park, mussel cages were placed in Pond 10 on the hatchery grounds, and in Dubuque at the River Museum, while larger juvenile mussels were in SUPSYs (Suspended UPwelling SYStems: buckets suspended in the water column with mesh bottoms and air flow that moves water through the bucket). October will be a busy month collecting juvenile mussels from these systems and getting them settled into their winter culture homes. By: Beth Glidewell