Genoa National Fish Hatchery (NFH) has been producing native aquatic species for conservation since 1932, and over the last 75 years it has grown into one of the National Fish Hatchery System’s most diverse field stations.

Genoa currently raises 23 species of cold, cool, and warm water fish and mussels for restoration efforts throughout the country. One of the challenges to raising so many different types of fish and mussel species is keeping culture facilities free of disease pathogens that could potentially be transferred from one species to another. The introduction of a pathogen to one of these 23 native species could spell disaster for the station’s programs and conservation commitments.

Careful planning and disease-hazard analysis help ensure the station maintains disease-free status and keeps it moving forward in restoration efforts. One key to disease prevention on station is production of a certified, disease-free source of forage for pond-cultured fish.

Fathead minnows are often used as a forage species for larger fish species cultured in the hatchery’s ponds. They are desirable as forage species because they are a nutritious, natural food for fingerlings, young-of-the-year, and brood and future brood fish, all of which are key elements to the success of Genoa NFH’s native species restoration programs. Fathead minnows are native to North America, which means that the risk of introducing a non-native species and associated pathogens to the hatchery grounds and surrounding environment is eliminated by using them as a food source.

Because fathead minnows are part of the hatchery’s production plan, they undergo health inspections for certifiable fish pathogens every six months. This ensures disease free status before being introduced to culture facilities and other cultured species. Genoa NFH has been involved in the production of fathead minnows since 1995, and this year produced 3,487,000 minnows to be used for the station’s restoration efforts as well as the efforts of Fort McCoy Army Base, Black River Falls Fish Propagation and Rearing Station, and Fairport (IA) State Fish Hatchery.

The minnows produced for Genoa NFH provide food for the fish that are used in many types of restoration activities. Throughout the summer months, minnows are harvested from ponds and fed to brood fish and young-of-the-year walleye, yellow perch, bluegill, black crappie, and large and smallmouth bass. Young-of-the year fish are stocked annually into tribal, state, and federal waters to enhance sport and subsistence fishing in these areas.

Yearling walleye, as well as blue catfish, channel catfish, and large and smallmouth bass, are also used to help recover wild populations of two endangered mussel species, the Higgin’s eye pearly mussel and the winged mapleleaf mussel. These species also make suitable host fish for several other threatened mussel species and species of concern used in propagation and research at the station. Genoa NFH cultures these species to be used as host fish for the first life cycle stage of these mussels.

Most freshwater mussels need a host fish to complete their first stage of development. In this stage, a larval mussel, or glochidium, must attach itself to the gill of a suitable host fish. The fish provides sustenance for the larvae, as well as safe habitat and transportation to a new, suitable habitat. When the glochidium completes development of this life cycle stage, it will drop off into the water and settle to the substrate, where it will begin life as a filter-feeding juvenile mussel. The mussel will continue to filter food from the water column and grow until it reaches sexual maturity and reproduces.

Genoa NFH’s goal for endangered and threatened mussels is to enhance survivability of the first life cycle stage until mussel populations become self-sustaining in the wild. Keeping host fish fit and healthy by feeding disease-free, nutritious minnows is a top priority for the program, which goes a long way in providing healthy juvenile mussels that will have a great chance for survival on their own.