Summer mussel propagation at the MARS trailer

Summer mussel propagation at the MARS trailer

The MARS (Mobile Aquatic Rearing System) mussel culture trailer is set up and running for the 2021 season at Blackhawk Park, a US Army Corps of Engineers facility just south of Genoa. This location allows us to securely park the trailer on the banks of Blackhawk Slough, and to pump river water directly up to the trailer, where it is filtered, UV zapped, and routed to 25 rectangular flow-through tanks. Each tank houses up to 250 sub-adult mussels, each about 1 inch long, or five thousand (or more!) newly transformed juvenile mussels that are about the size of a grain of sand.

Each year is different when dealing with water levels- after a couple of years of delayed trailer deployment due to high water and last year’s surprisingly ‘normal’ water levels (the only thing normal about 2020!), this year we’ve been dealing with low water situations. Low water helped simplify set-up (a big thank you to Jeff and Zach!), but reduced flow and connectivity to the main channel reduced water quality, especially dissolved oxygen in Blackhawk Slough, and reduces flow capacity from the pump. Just as we were considering starting contingency plans, much needed rains came and raised the water levels back to functional levels in mid-June.

This year’s MARS trailer group includes two sub-adult cohorts of Higgins eye, a group of Spectaclecase mussels propagated by the MN DNR, Fatmucket, and small cohorts of Sheepnose and Lilliput mussels. The newly transformed 2021 cohorts began in late June, and now include Pocketbook, Black Sandshell, Hickorynut, Lilliput, and two sub-groups of Higgins eye, including fifty thousand -and counting- juveniles produced from parents in the St Croix River. Watch for pictures of these juveniles on Genoa’s Facebook page, and an article later in the year reporting their growing season progress!

By: Beth Glidewell


Newly transformed Higgins Eye that will spend their first growing season in MARS tanks. Each juvenile is ~0.3 mm long (or about 1/80th of an inch) when they go into the tanks at the start of the season. Photo: Beth Glidewell

Dairyland Power adds exhibits to the Great River Road Interpretive Center



Dairyland Power Cooperative has been a valued partner in conservation with the fish hatchery for the past several decades. Their commitment to our conservation mission manifested itself recently by supplying an accessible fishing dock to one of our ponds in order to hold targeted fishing events and supplying a peregrine falcon display in our newly added Interpretive Center. The exhibit highlights their conservation work with this species. Recently during a scheduled Dairyland employee tour of the new Center, it was suggested that there was also an interesting bit of local history that would add to the Centers mission of pointing out local stories of historical interest. In fact, two topics emerged that really piqued our interest to use the Center to point out historical and conservation stories of the area. The first was to capture the story of the construction and final disposition of the Genoa’s prototype LaCrosse boiling water nuclear reactor, the first in the nation.

This pictorial story was compiled by Dana Bolwerk, Communications Specialist for Dairyland. The exhibit is currently in the local history wing in the Center. The next addition was to add a live camera feed of nesting adult peregrine falcons on the smokestack chimney of Dairyland’s Alma Wisconsin Power Plant. The nest and its two adults fledged 4 birds this year alone. During the off nesting periods the story of Dairyland’s Peregrine Falcon restoration efforts are described in a PowerPoint Display. We could not have added this exhibit without the help of Dairyland’s Environmental Biologist Ben Campbell and IT Specialist Mark Abitz.

We are very pleased with the addition of these fascinating local stories and feel that they truly help the Great River Road traveler understand the intrinsic history and conservation stories of the Upper Mississippi River region. Please come in and check them out! By: Doug Aloisi

Technology to Monitor Pond Production of Mussels

The last couple years at Genoa NFH, we’ve been experimenting with different methods of growing out juvenile freshwater mussels along with Largemouth Bass in productions ponds. This field is relatively new without a lot of past research to draw from. The pond environment is quite different than the river environment that our riverine species are accustomed to, but we’ve had some successes to go along with the failures. We’ve been able to point to temperature and pH as two potential water quality variables that may have limited success in the past. To combat that, we’ve installed real-time monitoring instruments that are able to transmit data wirelessly to our computers. This will allow us to respond more quickly as issues arise to mitigate for those issues and hopefully keep our baby mussels happy. Stay tuned for the next chapter of this story this fall!
By: Nick Bloomfield

Zach installing the control box at Pond 14 North

Snuffbox Or we all enjoy catching a fish; even freshwater mussels

In collaboration with the WI DNR, GNFH is planning to restore Snuffbox populations in the Wolf River basin. Last fall, WI DNR biologists spent some chilly dive days aggregating males and females to ensure that brooding females could be found this spring. The first tiny babies (~150 ?m long) are expected soon. Soon these will go out into the Mobile Aquatic Rearing System at Blackhawk, the U.S. Army Corps Park, to eat the natural food in Mississippi river water (bacteria and algae) and grow large enough to overwinter well at the hatchery for release in 2023.
Snuffbox is a particularly favorite species as it’s the only widespread member of their genus, all of whom catch their host fish. This unexpected behavior begets novel characteristics (‘toothed’ shell edges, the capacity to sit open, exposing their body cavity to the environment) making these species fascinating to observe. How these behaviors and morphologies, or physical characteristics in biology jargon, have developed and been maintained is fascinating to consider. We look forward to sharing more information about this species and others reared at the hatchery as our buildings open to the public and events develop in the coming years.

The group of broodstock Snuffbox, freshly tagged and ready to be returned to the river.

Snuffbox use log perch as hosts.

2021 Hines Emerald Dragonfly hatch complete at GNFH

The Hine’s Emerald Dragonfly eggs that GNFH has been housing since the end of December have all hatched. The eggs were held at 39-41 degrees over the winter and, in early April as the outside temperatures began to rise, we began warming the eggs. By end of April they had warmed to 60 degrees, and almost 1000 larvae had hatched. Egg cups were checked every day, and the day’s newly hatched larvae were placed in small specimen cups of pond water with a few zooplankton items as food.
These juveniles were then distributed into small rearing cups either individually or in groups of two or three individuals per cup. These cups, kept in groups by maternal line, are being housed at 60 degrees and fed three times a week by pipetting pond water with concentrated zooplankton filtered out of the pond water that comes through the mussel building. Food water is checked for larger pests that will view the dragonflies themselves as food (for example chironomids, some species are predatory). The remaining copepods, ostracods, cladocerans, and an early April bloom of rotifers- which appear to be a preferred food for new instar larvae- are available for the little dragonflies to hunt as prey.
After the larvae grow past their first few instars in these protected cups, they’ll move up to the next stage- small pvc and mesh cages submerged in a larger volume of water, with more food available. Individuals have to have grown large enough to stay enclosed in mesh with 500-micron openings—this size is large enough to allow water flow to bring in oxygen and new food items in without clogging too quickly the our productive pond water with algae and detritus. The photos below (bottom row) show an early and later instar juvenile on this screen as a check to see if this mesh size will contain the individual (answers: not yet, and yeah, definitely!).
By: Beth Glidewell

A three week old and 5 month old dragonfly larva on the same size mesh screen. Photos: Beth Glidewell/USFWS.


Walleye Spawning Season Comes and Goes

After a missed year of spawning Walleye on Pool 9 in 2020 due to the pandemic, we were back in action this spring. A strange spring it was weather wise for us in Western Wisconsin. We put our nets in on April 5 and started spawning fish on April 6. An unseasonably warm spell following a cold snap had temperatures rise 10 degrees from 44 F to 54 F in only three days, peaking at 58 F a couple days later which blew right through the typical spawning temperatures (around 45-50 F). A cold snap brought temps back down into the mid 40’s the following week. The fish seemed to be confused as well.
We never saw the typical “bell curve” of spawning activity slowing rising to a peak before slowly falling off. Numbers of ‘ripe’ fish were inconsistent until falling to near zero by April 22 when we pulled our nets. We likely missed a few of the early spawners over Easter weekend with the significant warm up, but we were able to send millions of eggs to our partners, stock our ponds for production, and return hundreds of thousands of eggs and fry back to the river.
By: Nick Bloomfield

Zach mixing milt with freshly collected eggs

Nick and Chelsea collecting newly hatched fry for stocking. Photos: Beth Glidewell/USFWS.














Mussel Recovery: planning during uncertainty

If you’ve been reading the newsletter for a while, you’re aware of the cycle of the year. Winter is for managing data and making plans, while spring is for preparation, summer is busy with hands on work with the mussels on station or in the river, then fall is bringing in the animals we’ve raised and settling them in for the winter. So much of that has stayed the same with the ongoing pandemic and but the planning has gotten more interesting. Winter is still important for being prepared for the year. We start by reviewing what was successful last year before deciding what our priorities are for the next. Some of this work includes assessing the status of cages, preparing dive gear for another season, and coordinating plans with our partners. We’ve had discussions with our various State and Federal partners, as well as the staff at the National Mississippi River Museum and Aquarium in Dubuque, about plans for the coming season. We’re still providing extensive care for several species of host fish and the many sub-adult mussels that are overwintering in the mussel building even as we finish construction on some new systems in the mussel building.
By: Megan Bradley

The new rearing pan system in the mussel building, with hoses delivering winter-temperature pond water and nutrients to the juvenile mussels that call these pans home from October-November until approximately June, when they’ll head to an outdoor culture system for the growing season. Photo: Megan Bradley/USFWS

Brook Trout Come Full Circle Back to Genoa

Orey displaying an adult brook trout that was part of the 2017 egg collection effort

The newest additions to Genoa National Fish Hatchery arrived on station in January. About 50,000 fertilized Brook Trout eggs were sent from our sister hatchery at Iron River. Hatching began almost immediately upon arrival in mid-January and all the fry were hatched out by the end of January. Staff have been busy caring for the eggs and fry ever since. These fish will live in the safety of the quarantine building until they have passed multiple fish health inspections. The treatment system in place in the Quarantine Building will keep the rest of the hatchery protected from any pathogens until we can ensure that there are none, at which point we can move them to a bigger rearing space. Once these fish are big enough to ensure a high survival rate in the wild, they will be stocked into the Lake Superior basin to help boost populations of Coaster Brook Trout.
The story behind the origin of these new arrivals begins in October of 2017. Eggs were collected from remnant populations of Coaster Brook Trout from the Isle Royal area and raised at Genoa NFH. This process was repeated the following year, and another batch grew up in the hallowed raceways of Genoa NFH. These fish weren’t destined for the wild, however. These two lots were destined for the FWS broodstock program and were sent back to Iron River NFH. Fast forward to 2021 and holding two distinct lots of broodstock that were becoming sexually mature, staff at Iron river NFH were able to cross them with minimal likelihood of relatedness between parents. These little guys will grow up in the same raceways their parents did, but they are destined to ultimately help grow the population along the shores of Lake Superior so Americans can enjoy them for generations to come.
By: Nick Bloomfield

A new season of Hine’s Emerald Dragonfly culture begins.



several hundred Hine’s Emerald Dragonfly eggs viewed through a dissection scope,

A few weeks before the New Year, a batch of Hine’s Emerald Dragonfly eggs arrived on station at Genoa NFH. This new cohort, approximately 1000 eggs collected from 6 females, are part of a collaborative captive rearing effort that Genoa has participated in since 2015, along with partners from the University of South Dakota, Illinois DNR, Forest Preserve District of DuPage County, IL, and the USFWS Chicago Field Office.

This season’s eggs are currently being kept in clean well water at a stable 4C, a temperature that delays hatching until conditions are more favorable in the spring. In late March- early April we’ll start warming the eggs and check daily for hatching juveniles. Until then, eggs are checked at least weekly, being monitored for early hatchlings and problems such as fungal growth.

So far there have only been a few early hatches. These new larvae are acclimated to pond water and slowly warmed to room temperature, 15-16C. The warmed pond water contains a variety of zooplankton that the dragonfly larvae- tiny but fierce predators- will utilize as food. The larvae will remain in individual culture cups for several months, protected from pests and growing larger size. When outside pond water has warmed to similar culture temperatures -May to June- the larvae will be placed in small mesh enclosures in rearing tanks in GNFH’s ‘dragonfly trailer’, and later into larger mesh cages in ponds at the hatchery for the 2021 growing season.

We also hope to culture Devil’s Crayfish on station this year. 2020 saw the addition of this species to the hatchery, as a culture trial to check the feasibility of culturing crayfish at GNFH. The animals on station did well, growing and successfully molting, so we hope this effort will continue in the coming years. Devils Crayfish are being studied and cultured in tandem with Hine’s Emerald Dragonflies as it has been observed that the crayfish make burrows and chimneys in wetland sediments that the Hine’s Emerald larvae utilize as habitat.

By: Beth Glidewell

a newly hatched larvae,