Summer Mussel Culture at Genoa NFH

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

School is back in session!

Have you ever considered the Genoa National Fish Hatchery as a destination for a school field trip? If not, you should! We offer age-appropriate outdoor education programs and tours that give students the opportunity to learn about the mighty Mississippi River, fish, mussels, local history and much more. Students will get the chance to hold live Lake Sturgeon, learn about different fish and mussel species and feed our hungry Rainbow Trout. There are many other activities available like exploring the Great River Road Interpretive Center by completing a scavenger hunt, hiking our nature trails, learning about birds, and identifying animal tracks. Field trips are offered throughout the entire year and can be customized for the changing seasons. We can now even offer the opportunity for students to try snowshoeing during the winter months! If any of these activities sound interesting, please contact Erica Rasmussen or 608-689-2605 to set up your field trip. Hope to see you soon! By: Erica Rasmussen

Students learning and exploring about mussels

Winged Mapleleaf takeoff for fall

Hatchery biologists joined partners from the Park Service the Minnesota-Wisconsin Ecological Services Field Office, U.S.G.S., and the University of Minnesota to search for displaying Winged Mapleleaf this year. Over the past 6 years we’ve experienced different patterns of flow and temperature across the fall and this year is different still, with very low water levels and cooler overnight lows. The Winged Mapleleaf responded and have been active early. We found the first female in full display in the shallows early in September. Partners or USFWS biologists have been out on the river at least twice a week since the end of August and we’ll continue until the first of October to confirm that we’ve collected great data about the pattern of reproduction this year. We have many plans for any mussel larvae, from collaborative projects with U.S.G.S., to producing juveniles for our own culture at the hatchery.
By: Megan Bradley


A Winged Mapleleaf in full display. She is ready to infest her host fish. The mantle magazine is the grey protuberance sitting at the center of the white to grey plate of inflated mantle that she will not pull back when disturbed. Her glochidia, or larvae, have been released into her mantle cavity in preparation for a fish mouthing at the magazine. If none arrives they’ll be ejected into the river after a day or so and she’ll burrow back down into the river bottom. Photo credit: Megan Bradley/USFWS.






Doug helping and holding a fish up next to kids at our Kids Fishing events at Genoa. Photo: USFWS.











Hatchery Swan Song
As most of you know, my tenure at the Genoa National Fish Hatchery and the Fish and Wildlife Service for that matter is swiftly coming to an end. I plan on retiring the end of August to pursue other passions such as sleeping in until 7 a.m., nurturing some grandchildren (who thankfully live close enough to nurture), and paying some much due love and attention to my bride of 40+ years, who has been faithfully supporting me throughout my working years. I would be reticent to forget to acknowledge all the people along the way that have supported me and walked with me on our shared mission of aquatic conservation over the 39+ years of the journey.

I have been blessed to have been supported by and worked with some of the most creative, intelligent, thoughtful, and dedicated people through this trip, which included family, friends, co-workers, supervisors, mentors, and partners. It even included people that just had a passion to try to make the world a little better by volunteering to help save it, one conservation task at a time. It includes my supervisors both immediate and regionally that pushed me to do something lasting and meaningful and to think outside the norms in order to “make a difference”. A shared love of the resource and its importance to conserve it is the glue that holds us together, but it is the people and their diverse talents, personalities, and interests that I am going to cherish the most. I also must acknowledge the people we have met and have come to love along the way in our 7 different locations throughout the journey. The church congregations, pastor/shepherds, and church families and “adopted parents and grandparents” that we have leaned on for support and friendship while we were miles away from our own families have been a literal godsend. Thanks again to all of you. I also must acknowledge the love and sacrifices of my wife and 5 children along the way. There have been times when moving away from our support groups was difficult, and many times I was not as present as I should have been. I apologize now and hope to make up for it.
In closing I would just like to say it has been a wonderful ride. Keep using the gifts that God has given you, whether they may be the working of your hands and minds to further conservation, or your service and hospitality to others. Thank you from the bottom of a grateful heart. Fare well and God bless.
By: Doug Aloisi

Summer Dragonflies at GNFH












The ponds and wetland areas at Genoa NFH are home to many aquatic insects, including the aquatic larval stage of dragonflies and damselflies. After hatching from eggs laid in the water or on emergent vegetation in shallow waters, the fully aquatic nymphs feed and grow for one or more years before they are ready to emerge as the terrestrial, flying adults we are all familiar with. The Wisconsin Aquatic Terrestrial Inventory (WiATRI), a program within the Wisconsin DNR that collects information from statewide surveys, lists 53 dragonflies and 31 damselflies species observed in Vernon County, and many of the more common species can be seen flying around the Hatchery during the summer. Some of the earliest fliers are Common Green Darners, which can be observed beginning in midApril – June, July and August are prime flight times for many species, such as the Common Baskettail, Prince Baskettail, and Widow Skimmer pictured here. Some species, such as the Autumn Meadowhawk, can be observed through October. The Hatchery is a great place to view dragonflies in flight all summer- the grounds are always open to the public, and the pond roads are a great place to walk and observe dragonflies and damselflies, birds, and other wildlife in a quiet, low traffic environment. By: Beth Glidewell


Each fall, hatchery biologists working with U.S. Park Service staff, MN DNR mussel biologists and staff from other U.S. Fish and Wildlife Service offices visit the St. Croix as many as 15 times looking for the federally endangered Winged Mapleleaf that thrive in the clean, clear water. Females holding mussel larvae are brought back to Genoa National Fish Hatchery, the larvae (glochidia) are allowed to attach to channel catfish and then the female mussels are returned to the St. Croix River. In the wild the larval mussels remain attached to the catfish until late spring when the water begins. In late May 2023 juvenile Winged Mapleleaf began to drop off at the Upper Midwest Environmental Sciences Center after they’d overwintered on channel catfish in their ponds. Some juveniles went into laboratory culture, while others were stocked into the Chippewa River. Around 3,000 0.3 mm juveniles were stocked in two events at a site where adult Winged Mapleleaf were reintroduced in 2016, and Higgins Eye were stocked in 2017. A quantitative survey of the site in 2021 showed that both species have survived and grown well alongside a large population of federally endangered Sheepnose. We hope that even a few of these Winged Mapleleaf juveniles will survive to adulthood and contribute to the genetic diversity of this reintroduced population.
By Megan Bradley

Photo: Biologists stock WML juveniles on the Chippewa River into a tube to allow them to settle in the mussel bed. Photo credit: USFWS.

Fathead Minnow Production at Genoa National Fish Hatchery

Fathead minnow fingerlings are used throughout the year as a forage base to feed hatchery captive broodstock as well as advanced growth largemouth, smallmouth, and walleye. These species feed on zooplankton and invertebrates as their primary food source when they are first stocked into hatchery ponds, as these fish grow, they switch to larger forage items, hence hatchery fathead minnows are stocked into ponds as their secondary food source. Prior to 2003, the bulk of fathead minnows used on station were purchased from private bait dealers in the area. This method was discontinued due to the risk of transmitting many unknown diseases from wild populations of fish to hatchery fish and to eliminate the risk of nuisance species such as brook stickleback. A fathead minnow brood line was developed at Genoa to prevent disease transfer and to reduce costs associated with the purchase of the wild baitfish.
In early spring approximately 50 gallons of broodstock fathead minnows are stocked into a 34-acre pond. During the summer these fish will spawn multiple times producing millions of new young of year fathead minnows. By mid-July, fathead minnows can be trapped using specially constructed minnow traps baited with dog food. This method results in variable catches of minnows per day using cloverleaf traps. The traps are available in a variety of mesh sizes to target different sizes of minnows. Hatchery staff irregularly set cloverleaf minnow traps around the pond by boat. Two people are required during the collection, a boat driver and another situated on the bow that can grab the float of each trap. The traps are emptied into an oxygenated 50-gallon tub filled with pond water in the center of the boat. After all the traps are collected and reset, the fathead minnows are transferred to a distribution truck and then to production ponds where minnows are measured by gallon and fed to production fish.
By: Orey Eckes

YCC student and staff getting ready to collect minnows in their boat. Photo: USFWS.

Upcoming Volunteer Opportunities at Genoa National Fish Hatchery!

• Lake Sturgeon tagging (August through Early September)

• Coaster Brook Trout tagging (September)

• Pond Harvest (September through October)

Call for more details! (608) 689-2605

Erica Rasmussen
Environmental Education Specialist Genoa National Fish Hatchery S5631 State Hwy 35 Genoa WI, 54632 608-689-2605

Cages Deployed

Over the years at the hatchery we’ve been working to improve how we manage ponds for mussel culture. Often the best conditions for growing fish don’t result in great algae and bacteria for growing juvenile mussels, so it takes lots of data collection and experimentation to find a balance between the two needs. This year we’re trying to culture our freshwater mussels in pond 10 right next to the mussel building. We placed our cages before the pond was filled. Our Youth Conservation Corps workers stocked the Largemouth Bass infested with Plain Pocketbook into the cages this week. The juvenile mussels will drop off into the sand in the bottom of the cages and hopefully grow and thrive. We added a tarp below this year’s cages to see if many of our juveniles are washing out of the cages due to fish movement or waves from storms. Any juveniles will be cultured to a large enough size to stock into Iowa to replace Plain Pocketbook killed in a spill. By: Megan Bradley

YCC workers place freshwater mussel infested Largemouth Bass into mussel culture cages at GNFH. Photo credit: Megan Bradley/USFWS.