Summer research is complete! Paige presented her work at the Midwest Fish and Wildlife meeting early in 2020 in Springfield, Illinois.  Strong work, Paige

CSB/SJU Summer Research

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Stumpf Lake and Lake Sagatagan

Summer 2019 kicks off summer research at St. John's University!



This year we are analyzing length at age for Northern Pike (Esox lucius) on Stumpf Lake as well as Large Mouth Bass (Micropterus salmoides) on Lake Sagatagan (Left)

Cross-section of Pike anal fin ray. This fish is aged 4 years

These campus lakes lack public launches and have lower fishing pressure than surrounding lakes.  We expect to see differences in length and age for these campus fishes when compared to similar local lakes that receive higher fishing pressure.  For aging structures, we are using a non-lethal method for Pike which uses anal fin rays.  For Largemouth Bass, fin rays do not reflect true age, so standard sagittal otolith methods are being used.

An otolith from a Largemouth Bass aged 17 years

Assisting with this research is Paige Folkerts, a Senior bio major from the College of Saint Benedict. Paige is a pre-vet student who has had an interest in fish from a young age.  She currently holds the record for the largest Pike (28") and smallest Pike (12") caught on Stumpf Lake. Paige has assisted in collection of Pike with different gear types, will be analyzing age structures on both Bass and Pike, and will create a poster to present her findings (coming soon). Additionally, Dr. Jen Schaeffer's research assistant, Amanda Bevan, is helping with Pike collection and is interested in pursuing a career in neuroscience.

Paige Folkerts and a 28" Northern Pike

Amanda Bevan determines length

Bass were collected early spring (55º surface) by electroshock with the help of Joe Stewig, the Sauk Rapids Area Supervisor.  We collected 44 Large Mouth Bass. Joe was kind enough to give a demonstration on electrofishing and take students out to net the fishes. Students also assisted in recording catch numbers, length and helped remove otoliths. 

Matt Captain (summer researcher) nets a LMB

Joe Stewig collects otoliths

Jess Torrison holds a 21" LMB

Pike have been collected via Fyke netting and angling.  Currently, we have 41 Pike and would like to have 2 fish per inch designation by the end of the summer. 

Additionally, we are also looking at how the gear type used for collection affects lactate levels in Bluegill (Lepomis macrochirus). This study is ongoing. 

Updates soon!

Light in lakes and forage habitat

Figure 1.  Capture probabilities for Siscowet Lake Trout at different light intensities

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Recently, we have been investigating how fish habitat changes with daily and seasonal light changes.  With the help of Bryan Matthias, a post-doc at UMD, we have created a light model for Lake Superior that predicts changes in Siscowet Lake Trout foraging habitat on an hourly, daily and seasonal time scale.

Figure 2. A photon of light's path through water

Using Siscowet prey capture data from Keyler et al. (2015), we are able to determine the light intensity associated with 50% prey capture during foraging trials (Fig. 1).  We can then calculate the depth within Superior associated with this light intensity throughout the day and seasons using the model.  

Figure 3.  Changes in solar altitude and angle with seasons

Our model accounts for reflection at the lake's surface, refraction by water, and attenuation within the water (Fig. 2).  Due to the angle and altitude of the sun associated with different seasons (Fig. 3), light penetrates deeper in the summer compared to the winter season. Siscowet forage habitat is therefore greater in the summer, than in the winter (Fig. 4).  

Additionally, we are working on calculating the daily light changes within Lake Superior as well as how light penetration, and respective siscowet forage habitat, will change with climate warming. 

Figure 4.  Solar maximum siscowet habitat depths for cross-section of Lake Superior (right) and associated geographical distribution (left) for spring, summer, fall and winter (from top) within the Western Arm of Lake Superior. 

Publication Link: https://link.springer.com/article/10.1007/s10750-019-3888-9

Undergraduate Research

Sarah Muellner and Julia Narow are seniors at UMD who just finished their UROP (undergraduate research opportunity program) projects.  Each helped with my research while conducting small studies of their own which they presented today at the UROP poster fair.

Sarah Muellner

Sarah's poster on juvenile walleye foraging

Sarah helped with the walleye foraging study looking at how water clarity and light intensity affect juvenile walleye.  This study will be completed within the next year.  Sarah is interested in fishes, particularity cichlids. She may have the opportunity to see some first hand during her next 2 years near Lake Malawi while working for the Peace Corp in Africa.

Julia's poster on treatment of barotrauma

Julia Narow

Julia has helped with the Barotrauma work on Lake Superior working with the USGS and Owen Gorman.  Julia helped compare how fish that were treated for decompression after being trawled from the deep waters fared compared to fish that did not receive the treatment.  Julia is interested in marine mammals and has an internship this summer rehabilitating marine mammals in Sarasota, FL.

Best of luck to you both and thank you for your help.

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