Every spring, as the early flood waters on the Mississippi River recede, we eagerly await time to launch the MARS (Mobile Aquatic Rearing System) mussel culture trailer. Placement of the trailer at Blackhawk Park, a USA Corps of Engineers facility right on the Mississippi River just south of the Hatchery is a wonderful long-term collaboration that allows us to greatly improve growing season success for many species of juvenile mussels. The trailer is cleaned and repaired at the Hatchery over the winter, then in late May or early June is moved to the Park, river water is pumped in to the trailer, filtered and UV sterilized, then piped to culture tanks. Outflow water is again UV sterilized and returned to the slough just down-stream.
The MARS trailer emptied and cleaned for over-winter storage at GNFH. Zach repairing electrical components that control the drum filter, which reduces sediment and potential pests from the inflowing water to the trailer. Rearing tanks being positioned in the trailer. Photo: Beth Glidewell/USFWS.
Juvenile mussels produced in previous years that need another summer of culture are placed in the culture tanks when the trailer is first set up, others will be placed in trailer tanks as they are produced over the summer. We currently have Washboard, Plain Pocketbook, and southern Higgin’s Eye new juveniles, and soon we’ll have Rock Pocketbook juveniles ready for culture in the trailer. Later this summer they’ll be joined by a northern population of Higgin’s Eye, Sheepnose, Salamander Mussel, and Giant Floater mussels. Older juveniles requiring an additional year of growth in the trailer this year include Fat Mucket, Spectaclecase, Sheepnose and Higgin’s Eye.

Larger juvenile mussels being added to trailer culture tanks.

Newly transformed juvenile mussels that will be placed in culture tanks with fine mesh screens. Photo: Megan Bradley & Beth Glidewell/USFWS.

These juvenile mussels fill up almost every tank in the trailer, so Genoa NFH staff check water flow and aeration, water temperature and basic water chemistry daily throughout the growing season. We check the filtration and UV systems and make repairs as needed, keeping the system running smoothly all season.
By: Beth Glidewell