DNR proposal acceptance

Just got word that our walleye foraging study has been approved by the SPA and we have funding for our fall study.

Our initial goal is to determine the effects of water temperature, water clarity and light intensity on young of the year walleye foraging. Due to increasing water clarities from invasives like dreissenid mussels, it is thought that the thermal-optical habitat needed to produce strong walleye year classes is on the decline.  Our study aims to tease out the habitat requirements needed for successful foraging.

Link to Brule River Sportsments Club page

Thank you to the Brule River Sportsmens Club. I greatly appreciate the 2016 scholarship award and am happy to be recognized by a group that works to protect and improve a river that means a great deal to me.  

Over the years, I have spent a lot of time on the Brule and it has become a mental refuge for me after stressful days in the lab.  I look forward to working with the members of the club in the future on a personal level and collaborating efforts with our own UMD AFS student subunit.

Read more below about the efforts of the Brule River Sportsmen Club or visit the link to their page above.

Right: A large brown caught on the Brule river with good friend and former grad student, Kirk Olson.

UW Trout Lake Station and Escanaba Research Station

This spring and summer I've been living at the University of Wisconsin, Madison's Trout Lake Station and working at the Wisconsin DNR Escanaba Research Station.

Trout Lake Station is operated by the Center for Limnology at UW Madison and located in northern Wisconsin. Graduate and undergraduate students spend their summers at Trout Lake conducting graduate work and individual research studies.

The station was established in 1925 as a place to study the lakes of Northern WI. Edward Birge and Chancey Juday, considered the founders of limnology, founded the station as a hub to determine the shared characteristics of northern lakes.

Escanaba research station

I started at the Escanaba research station in early May working for Dr. Gregory Sass.  The Esacanaba station has the longest continuous creel survey within the United States which began in 1946.  I've been involved in assessing the five research lakes associated with the station including Escanaba, Nebish, Palette, Spruce and Mystery and helping with the creel.

Escanaba lake at dawn

Each spring and fall, the fish communities are assessed on these lakes using various gear types including fyke nets, gill nets and electrofishing.  In July, we will start the cisco survey on the lakes via gill nets.

Jamie and Austin prep of plankton samples

We also conduct limnology studies on the 5 research lakes biweekly.  Limno includes phytoplankton sampling via wisconsin plankton nets, chlorophyll a readings to assess productivity, dissolved oxygen/temp profiles and secchi readings.

Checking fyke net on Sandford experimental lake

Another long term study being conducted on Sanford lake is looking at the effects of the addition of course woody debris (CWD).  This spring, the fish community was assessed pre-CWD addition.  The lake will be reassessed every five years to look at how fish populations change.

Dissolved oxygen and temperature profile readings

Additionally, Dr. Sass, Dr. Hrabik and I have written a grant for the WI DNR to fund a study on the effects of water quality, light intensity and temperature on walleye foraging.  This study currently has three objectives: 1) Determine foraging characteristics of adult walleye including reaction distance, angle of attack, and foraging success for ecologically relevant light intensities, temperatures, and water clarities, 2) determine effect of these variables on foraging success for young of year (YOY) walleye, and 3) assess YOY walleye predator avoidance of Large Mouth Bass under these variables. Currently, the status of the grant is pending.




Lastly, I have been analyzing creel surveys to look at angler demographics.  Specifically, we are interested in whether there are harvest rate differences for angler sex, age, travel distance and seeing how these change over time.

Above photos show taking Chlorophyl a readings (left) elctrofishing on Nebish lake (middle) and collecting phytoplankton (right)

This week I also presented some of the research we've been doing at UMD for the weekly Trout Lake seminar.  Research topics covered included siscowet vision and foraging, lake trout vision, walleye vision and the proposed walleye foraging study.

49.5" Musky caught in fyke net on Escanaba lake

Big thanks to IAGLR

Water Action Week

Click HERE for link to MN water action week

This week I was able to meet with Larry Pogemiller, John Downing and Chancellor Black to discuss the importance of Lake Superior research.  Larry Pogemiller is the Commissioner of the Minnesota Office of Higher Education appointed by Governor Dayton and came to discuss fishy topics as part of the Governor's Water Action Week.

Discussing invasive species with Larry Pogemiller

Chancellor Black, Larry Pogemiller and John Downing 

This April 17 – 23, 2016, is to be Water Action Week in Minnesota. Throughout the week, Governor Dayton will visit school classrooms, water treatment facilities, research institutions, and farms to encourage Minnesotans to learn more about the challenges facing Minnesota’s waters, and empower every individual to take actions in their own lives to be part of the solution.

This was a great opportunity to showcase the freshwater research, outreach and education at the University of Minnesota and talk about the research being done with John Downing, the MN Sea Grant director, and Chancellor Black from UMD.

Photos courtesy of Sharon Moen, MN Sea Grant

Link to complete article

Loranzie (L.J.) Rogers has been assisting with research in the lab since last summer and has been an invaluable asset to the lab.  So far, L.J. has conducted his own study on siscowet vs. lean lake trout vision, aided in electroretinography of walleye and is now helping with foraging trials. Read more about L.J. below.

Michigan Bound

This week, LJ Rogers and I went to Michigan for the annual Midwest Fish and Wildlife Conference to present our work on the scotopic visual sensitivity of walleye.

LJ and I at poster presentation night

Sander Award

We also attended the walleye technical committee where we got to talk about the future of walleye research and explain the work we are doing at UMD.

Near-Shore vs. Off-shore Predators: Morphotypical Variation in Vision?

Within Lake Superior there are currently 4 different morphotypes of Lake Trout identified (Figure 1); morphotypes are the same species, but show phenotypic and genotypic variation. We wanted to investigate whether the 2 morphotypes, Siscowet and Lean Lake Trout, had adapted different visual properties owing to their different habitats (Figure 2).  The Lean Lake Trout is a littoral or near-shore morphotype that occupies water less than 80 meters deep and historically has less body fat.  In contrast, the Siscowet Lake Trout is a pelagic (off-shore) morphotype that occupies waters greater than 80 meters and can have up to 70% body fat. Both are apex predators within their respected zones.

Figure 1.  The 4 morphotypes of Lake Trout within Lake Superior

The two morphotypes also display different behavior.  Lean Lake Trout perform Diel Bank Migration (DBM) where they move into shallower, near shore waters in the evening, while Siscowet perform Diel Vertical Migration (DVM) characterized by moving higher in the water column at night (Figure 3).

Figure 2. Characteristics of Lean vs. Siscowet Lake Trout

With the help of data published in a previous study entitled Visual Sensitivity of Deepwater Fishes in Lake Superior by a former lab mate, Kelly Harrington (photo), we were able to compare the visual properties of Siscowet Lake Trout to the data we collected on Lean Lake Trout.  Additionally, L.J. Rogers collected Lean Lake Trout with the help of the DNR (photo), helped analyze and collect the data and was able to complete a UROP project (Undergraduate Research Opportunities Program).

Figure 3. Diel (Daily) migration patterns for Lean and Siscowet Lake Trout within Lake Superior. A, Day; B, Night.

For this study we wanted to determine which colors of light Lean Lake Trout see and at what intensities. To do this, we conduct electroretinography, or ERG, for short.  These ERG's essentially tell us when neurons are firing in response to a color and intensity of light; we can then quantify based on the response.  The ERG setup is outlined below (Figure 4 and in short, involves flashing monochromatic (one color) light at different intensities and recording the neural response.

Figure 4: Schematic drawing of electroretinography setup. From left to right: (A) Constant current power supply, (B) electric shutter, (C) quartz-tungsten halogen lamp, (D) neutral density filters, (E) monochromator, (F) Faraday cage, (G) fiber optic light pipe, (H) recording electrodes, (I) signal amplifier (G-I within circular enlargement), (J) PowerLab, (K) personal computer, (L) chilled water lines.

Left: L.J Rogers holds a Lean Lake Trout he collected this past fall with the help of the MN DNR. Right: L.J. Rogers, Kelly Harrington and myself taking a break from conducting ERG trials.


When we analyzed our Lean Lake Trout data and compared to Siscowet data in Harrington et al. (2015), we see that there are some differences in visual sensitivity between the two morphotypes. Lean Lake Trout have peak sensitivity at 550 nm (green) while Siscowet have peak sensitivity at 525 nm (blue-green) (Figure 5).  We also see that Leans have green-shifted vision with higher sensitivity to the upper wavelengths.  In contrast, Siscowet are blue-shifted and show higher sensitivity to the blue range of wavelengths.

As blue green wavelenths penetrate deepest in freshwater, this supports the sensitivity hypothesis that a fish will be most sensitive to the light available in its environment. The siscowet is most sensitive to 525 nm blue-green light which is the only light available at depth.  In shallower waters, the green wavelengths have yet to attenuate and can be sued by a visual predator like the Lean Lake Trout. Green wavelengths also penetrate furthest in turbid waters and may aid Leans in shallower, wave agitated areas.

Figure 5.Visual sensitivity of Lean and Siscowet Lake Trout.

By determining the lowest intensity light each morphotype can detect, we can equate this to what depth a fish might be able to see.  We determined that Siscowet and Lean Lake Trout have the same depth profiles for vision and both are able to detect light ~350 m within Lake Superior in the summer.  In fall, with an increase in lake turbidity, vision is limited to ~100 m.  This data suggests that while Siscowet and Leans have evolved different sensitivities to different wavelengths, they have yet to develop absolute sensitivity differences.

LJ received an award this spring at MN AFS for the above work

American Fisheries Society Student Subunit at the University of MInnesota, Duluth

In May of 2015, we established the first American Fisheries Student Subunit at the University of Minnesota, Duluth.

We have 25 active members and are comprised of both undergraduate and graduate students.

We have bi-weekly meetings and our scheduled activities revolve around conservation and fisheries education.



Mission Statement :  A club for students interested in strengthening their fisheries knowledge, advancing fisheries science, and conserving fisheries resources and aquatic systems within Minnesota.

UMD AFS graduate students at MN AFS

To date, we have coordinated beach cleanups with MN Sea Grant, visited the Great Lakes aquarium, judged the regional science fair, volunteered at both the Boat show and Home show, written letters of support for Lake Superior Marine Sanctuary, designed the MN AFS T-shirt for the annual meeting, collected for the MN AFS annual meeting auction and gone smelting as a group.

Collected 55lbs of trash of the shore of Lake Superior on Mn Point

T-shirt design for the MN AFS annual meeting

UMD AFS volunteering at the Boat show with MN Sea Grant

Field trip learn about fish husbandry at the Great Lakes Aquarium

Using the seine net to capture smelt during our annual UMD AFS smelt event