A Mussel Delivery Three Years in the Making
When I arrived at Genoa National Fish Hatchery (NFH) in August 2010, the first project I was handed was to provide mussels of three different life stages (larval, juvenile, sub-adult) to the USGS lab in La Crosse for testing to determine if a biocide capable of killing the exotic zebra mussel was also toxic to native freshwater mussels. The project called for seven different species ranging from common to Federally Endangered.
During 2011 and 2012 we provided mussel larvae and juvenile mussels from each of the seven species and the first two phases of the project were completed. Also during that time we placed mussel culture cages at multiple locations holding fish inoculated with our target species. Each year we would collect and set aside the species that had been successfully cultured, waiting for the lab to be ready to conduct the test. Any species that was not successfully cultured was attempted the following year.
When trials were scheduled for May 2013 we had to wait for the ice to thaw from the river before venturing out to see how our test subjects had held up. Turns out we were successful in growing an appropriate number of four of our target species (hickorynut, fatmucket, plain pocketbook, Higgins’ eye). We were able to acquire a fifth species, the washboard, from the mussel propagation lab at Missouri State University in Springfield, Missouri. It was decided that the final two species could be collected from the wild and so Genoa NFH divers spent a sunny Friday afternoon in May submerged in the dark deep waters of the Mississippi River. At the end of the day they arose from the water victorious with enough mussels to conduct the experiment. All seven species were tagged by USGS biologists so individuals could be monitored throughout the study.
Clockwise from top: threeridge, Wabash pigtoe, hickorynut,
washboard, Higgins’ eye, plain pocketbook, fatmucket,
Credit: USFWS
On May 28 they all left Genoa NFH and headed for test chambers at the USGS mobile lab. The chemical was exposed to the mussels and they were then placed in a Genoa NFH style mussel cage to monitor post test survival for 30 days. At the end of that time the cages will be retrieved and all the living and dead mussels will be counted. Lots of live mussels will mean that the chemical is safe for native mussels, while dead mussels mean the opposite. It is expected that they will survive the experiment, after which they will be returned to Genoa NFH and incorporated into other restoration projects. Either way we were able to accept the responsibility of the large mussel order and deliver every species and life stage at the appropriate time.
