Friends of the Upper Mississippi

Staff from the La Crosse Fish Health Center visited the hatchery as part of a bi-annual fish health inspection. The Fish Health Center provides fish health inspection and diagnostic services for six national fish hatcheries and numerous tribal hatcheries throughout the region. In the spring staff sample hatchery production fish for possible pathogens or diseases. The results of these surveys ensure quality fish being stocked in the fall each year. In addition to hatchery production samples, Genoa provides a variety of fish from the Mississippi River for the fish health center as part of ongoing national wild fish health surveys. These sample collections and surveys allow fisheries managers to prevent and diagnose hatchery and wild populations of fish for pathogens or diseases. These results allow safe transport and stocking of healthy fish throughout many regions.
By: Orey Eckes

Fish health biologist, Eric Leis samples lake sturgeon. Photo Credit: Jadon Motquin/USFWS

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

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

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.

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.