Author Archives: Packerland Team

2021 Winnebago Walleye Survey Efforts

The Oshkosh fisheries work unit and Asylum Bay operations staff have completed the 2021 walleye spawning stock assessment. The objectives of the survey included tagging adult walleye to estimate annual exploitation, evaluate size structure, conduct age and growth analyses on male aging samples and evaluate spawning marsh conditions. Survey efforts began on the Wolf River on March 21 and continued through April 5. Water level gauge height at the USGS New London site ranged from about 7 feet on March 21 to 6.2 feet on April 5.

The lack of rain and snow this year led to fairly low water levels on the Wolf River during the peak walleye spawn compared to recent years. Water levels and flow in the main marshes around New London and Shiocton were marginal. Generally, a gauge height of at least 7 feet is needed to provided marginal conditions, with more ideal marsh conditions occurring when gauge height surpasses 8 feet. 

In total, 3,703 adult male and 852 adult female walleye were sampled on the Wolf River. That was near the annual goal of tagging 5,000 in the Wolf River. In addition, 72 adult male and 9 adult female walleye were sampled on the upper Fox River near Princeton. Peak spawning activity was observed throughout the week of March  25 and mostly wrapped up by early April. The strong 2016 year class was well represented during survey efforts, with males ranging 13-15 inches and females ranging 15-18 inches.

Tagging efforts included continuing the reward tag study and the release of 100 male and 100 female reward tagged fish. These tags are worth $100 for anglers that catch and report a pink reward tagged fish. The tag reward for this year’s tags will expire on March 31, 2022 and are being paid for by Battle on Bago. This study will continue to provide more accurate annual exploitation and angler tag reporting estimates. DNR staff also conducted walleye electrofishing surveys on the Upriver Lake and Lake Winnebago.

The objectives of the survey primarily include tagging immature (unknown male or female) and immature female walleye to estimate annual exploitation. Adult males and females sampled are also tagged. Overall, 372 immature, 243 immature female, 119 adult female and 642 male walleye were sampled. Immature walleye sampled mainly ranged 11-14 inches and immature female walleye ranged 14-17 inches.

Anglers can report the catch of a tagged walleye, yellow perch, bass, or northern pike by mailing the catch information to the Oshkosh DNR office (625 East County Road Y, Oshkosh WI 54901), emailing it to DNRWINNEBAGOSYSTEMTAGRETURNS@wisconsin.gov or calling 920-303-5429. If you have any questions about the trawling report or this year’s survey update, please feel free to reach out.

Lake Winnebago Trawling Report

The Wisconsin Department of Natural Resources (DNR) recently published the 2020 Lake Winnebago Trawling Report, which discloses the results of the trawl assessment conducted on Lake Winnebago. This assessment has been conducted annually since 1986, and the main objectives include providing critical information on year class strength of game and nongame fish species, monitoring trends in the forage base and monitoring general population trends of game and nongame fish species. Overall, there were 15 species of young of year (YOY) fish sampled for a total of 79,835 YOY fish caught during the 2020 trawling survey. For adult ­­­fish, there were 18 different species sampled for a total of 42,480 adult fish captured. The 2020 trawling results revealed several highlights, including record catch rates of YOY freshwater drum and yellow perch, a strong crappie hatch and a measurable walleye year class. I hope you enjoy the report.

Diets of Larval Walleyes in Northern Wisconsin Lakes

Nathan Jaksha1, Daniel Isermann2, & Daniel Dembkowski1

University of Wisconsin-Stevens Point1, USGS-Wisconsin Cooperative Fishery Research Unit2

Introduction

  • Walleye are an important species in Wisconsin that support both recreational hook-and-line and tribal spear fisheries.
  • Walleye recruitment has declined in some lakes that previously supported natural recruitment yet has remained stable in other lakes.
  • Recent studies suggest that a recruitment bottleneck may be occurring at or before the larval stage in lakes exhibiting declines in natural recruitment.
  • Reasons for the contrasting trends in recruitment among populations are unclear, as are mechanisms underlying the recruitment bottleneck in lakes with declining recruitment.
  • Differences in prey availability among lakes with different recruitment histories could contribute to the observed trends in recruitment.
  • Assessment of larval walleye diets from lakes with different recruitment histories could provide important insight to the role of prey resources in explaining trends in walleye recruitment in Wisconsin lakes.
Photo of an adult walleye sampled by the Wisconsin DNR

Objective

Describe diet composition of larval walleyes in northern Wisconsin lakes displaying two different recruitment histories: sustained natural recruitment (S-NR) and declining natural recruitment (D-NR).

Methods – Sampling

  • Larval  walleye sampling occurred during 2016 & 2017 on 13 lakes
    • Five of these lakes were resampled in 2018
  • Sampling started mid-May each year
    • Continued at 7-10 d intervals until early June
    • Surface temps = 11-16˚C
  • Larval walleyes were collected using a 1,000-µm mesh conical ichthyoplankton net.
    • Towed at surface (5 min) at both nearshore (within 100-m) & offshore locations (≥100-m) at night
  • Percid larvae identified to species using dichotomous keys
    • Random subset selected for genetic verification of visual species identification using PCR techniques

Methods – Diets

  • Gut contents of each fish were removed and diets were quantified using mean percent composition by number of individual diet items.
  • Zooplankton items classified to order for adult copepods and genus for cladocerans
  • Larval fish encountered in diets identified genetically using qPCR techniques
Magnified image of a zooplankton (Daphnia spp.) diet item
Magnified image of a larval Walleye

Results – All Lakes

  • Larval walleye collected from 6 S-NR lakes and 4 D-NR lakes (diets summarized in Table 1).
  • Guts were removed from 115 larval walleyes (mean TL = 11.4 mm; range = 6.4 –22.0 mm).
  • 27% of diets (31 of 115) were empty
  • 37% of diets (42 of 115) contained larval yellow perch
  • 16% of diets (18 of 115) contained zooplankton

Table 1. Mean percent composition by number and counts of prey items observed in larval walleye diets from all lakes combined.Search:

DIET ITEM% COMPOSITIONCOUNT
Daphnia spp.15.041
Calanoid Copepods1.83
Cyclopoid Copepods5.816
Bosmina spp.0.53
Larval Fish63.349
Unidentifiable13.510

Showing 1 to 6 of 6 entries

Results – S-NR vs. D-NR Lakes

  • S-NR Lakes = 86 larval walleye (diets summarized in Table 2)
    • Larval walleye mean length = 11.3 mm (range = 6.5 -22.0 mm)
    • 38 % of diets (33 of 86) were empty
    • 31% of diets (27 of 86) contained larval yellow perch
    • 20% of diets (17 of 86) contained zooplankton
  • D-NR Lakes = 29 larval walleye (diets summarized in Table 2)
    • Larval walleye mean length = 12.4 mm (range = 7.8 -21.0 mm)
    • 28% of diets (8 of 29) were empty
    • 52% of diets (15 of 29) contained larval yellow perch
    • 3% of diets (1of 29) contained zooplankton

Table 2. Mean percent composition by number and counts of prey items observed in larval walleye diets from S-NR and D-NR lakes.

RECRUITMENT HISTORY:S-NR LAKESD-NR LAKES
Diet Item% CompositionCount% CompositionCount
Daphnia spp.19.1404.81
Calanoid Copepods2.530.00
Cyclopoid Copepods8.1160.00
Bosmina spp.0.730.00
Larval Fish60.13471.415
Unidentifiable9.4523.85

Discussion

  • Larval yellow perch were the dominant prey item for larval walleyes in lakes exhibiting both sustained and declining natural recruitment.
    • Extent of piscivorymuch greater than previously assumed
  • In general, larval walleyes in S-NR lakes consumed a greater diversity of prey items and more zooplankton than larval walleyes in D-NR lakes.
  • Further statistical analyses required to determine if diets and prey availability differed between S-NR & D-NR lakes.

Acknowledgements

  • This study was funded by the Wisconsin Department of Natural Resources through the Fisheries Analysis Center at the University of Wisconsin-Stevens Point.
  • Jason Gostiaux
  • Walleyes for Tomorrow: Research Fellowship

U.S. Fish and Wildlife Service Seeks Public Input to Increase Access to Refuge System Lands

As part of its ongoing effort to increase public access on federal lands, the U.S. Fish and Wildlife Service today announced (news release attached) it is seeking the public’s assistance to develop a list of its managed lands that would benefit from new or increased access routes. 

On March 12, 2019, President Donald Trump signed into law the John D. Dingell Jr. Conservation, Management, and Recreation Act (S.47, the Dingell Act), which directs the Service and other federal land management agencies to develop a priority list of lands that have significantly restricted or no public access where that access could be improved. The public is encouraged to identify national wildlife refuges, fish hatcheries and other lands managed by the Service that meet the complete criteria. 

Comments will be accepted over a 30-day comment period from February 10-March 11, 2020. 

Some of the criteria for nominated lands include: public lands must be managed by the Service and 640 contiguous acres; have significantly restricted or no public access; and be open under federal or state law to hunting, fishing, or use of the land for other public recreational purposes. 

For additional information and a full list of required criteria for consideration as specified by the Dingell Act, visit: https://www.fws.gov/refuges/realty/Public-Access-Nominations.html

Commenters are encouraged to review the required criteria and include additional information as to why the parcel should be on the Service’s priority list. Once the comment period closes the Service will evaluate the nominations to determine which lands meet the requirements and considerations specified by the Dingell Act.

Expanded Assessment of Recruitment Bottlenecks for Age-0 Walleye Sander Vitreus in Northern Wisconsin

A Thesis Submitted in partial fulfillment of the requirements of the degree
MASTER OF SCIENCE IN NATURAL RESOURCES (FISHERIES)
College of Natural Resources UNIVERSITY OF WISCONSIN
Stevens Point, Wisconsin

Many northern Wisconsin lakes that historically supported naturally-recruiting walleye Sander vitreus populations have shown declines in recruitment over the last 10-15 years. Previous research conducted on four northern Wisconsin lakes suggested a recruitment bottleneck was occurring before mid-July in lakes with declining walleye natural recruitment. Effective management of walleye populations involves understanding these recruitment bottlenecks, as potential management solutions may vary in relation to when and why this recruitment failure is occurring. To further assess these recruitment bottlenecks, I expanded on the previous assessment to determine if: 1) timing of a recruitment bottleneck for age-0 walleyes was consistent among lakes with declining
recruitment; 2) abiotic and biotic metrics differed between lakes with declining (D-NR) and sustained (S-NR) walleye recruitment, with a specific focus on the abundance of edible zooplankton and 3) catch-per-effort (CPE) of larval and post-larval walleyes can be used to predict the presence, absence, and relative strength of walleye year-classes indexed by standard fall electrofishing conducted by the Wisconsin Department of Natural Resources and the Great Lakes Indian Fish and Wildlife Commission.

Walleye are Spawning – Thesis

Hadley Boehm was the grad student who did the walleye research under Dan Isermann last year. She graduated, got a job with the Minnesota DNR, and then finished her thesis, a copy of which is attached. The research is continuing….

The short version is: Walleye are spawning, then the fry are showing up in some lakes, and not showing up in other lakes. No fry = no YOY in fall. And nobody knows why.

Click here to read Thesis

2014 STATUS OF WALLEYE IN SOUTHERN GREEN BAY AND THE LOWER FOX RIVER

image003This report contains length distribution of Walleye captured during 2014 spring electroshocking on the Fox, Oconto, Peshtigo and Menominee Rivers.

Charts also show active year classes.

Background
Walleye stocks in southern Green Bay were decimated during the early to mid-1900s by habitat destruction, pollution, interactions with invasive species, and from over-exploitation. Following water quality improvements in the early 1970’s, the Wisconsin Department of Natural Resources began to stock fry and fingerlings to rehabilitate the Walleye population.

Stocking began in the Sturgeon Bay area and later expanded to include the lower Fox River (downstream from the DePere Dam). This stocking (fingerlings and fry) was so successful in southern Green Bay and the lower Fox River that it was discontinued in 1984 to allow surveys to determine if substantial natural reproduction and recruitment was occurring.

However, stocking in the Sturgeon Bay area resumed in 1994 and continues with a mix of fry and fingerling being stocked to augment the population. The total number of number of Walleye stocked in Wisconsin waters of Green Bay has varied by location and year with over 70,000,000 fry and 4,500,000 fingerling stocked into Green Bay and the Fox River since 1973.

Click Here to see full report along with year classes of walleye that are in Green Bay

WDNR Fisheries staff with tagged walleye

We look forward to working with our local DNR staff in not only increasing habitat, but education about the walleye as well with work being done at the Peshtigo River

Photos of
• Anglers lined up in the lower Peshtigo River in the spring.
• A big female. Look closely at the base of the dorsal and you can see a green floy tag.
• Closer up of a floy tag.
• 2012 survey on the lower Peshtigo River. Left to right WDNR fisheries staff Ron Rhode, Tammie Paoli, Rod Lange, Brad Ryan.
• Crew and shocking boat on the lower Peshtigo.
• A walleye with lymphocystis (and a yellow floy tag). In the spring, we get quite a few calls about fish having warty growths on them. Lymphocystis is a viral disease that is seldom fatal that seems to peak in the spring during colder temps and spawning stress…

March 11, 2016 WFT Green Bay Banquet

We are a 501c3 non-profit organization that raises money locally with 100% of all money being raised being spent here in Northeast Wisconsin.
Local projects have included:
• Develop rod & reel loaner program for Boys & Girls Club
• Take special needs kids on a fishing day
• Support and supply rods & Reels for kid’s education seminars on fishing
• Purchased $5,000 micron microscope for DNR for fish disease prevention
• Assisted in building handicap fishing pier in De Pere
• Built spawning reef outside of the mouth of the Fox River by Bay beach
• Built spawning reef along the East shore the bay of Green Bay
• Developed habitat on west shore Peshtigo River for walleye spawning.

Our banquet is March 11, 2016 at the Stadium View and your support is both greatly appreciated and needed in order to carry on our volunteer work. We will include promotional items and display of posters or brochures provided during the event.

Get Your 2016 Tickets

If you have any questions, Please give me a call at 920-826-5901.

Peshtigo Flowage – Walleye Spawning Reef

PESHTIGO – Generous funding from several partners and a window of opportunity during a dam repair allowed DNR and partners

to build a walleye spawning reef in the Peshtigo Flowage below Potato Rapids Dam.

The project involved adding 300 tons of glacial stone to create a walleye spawning reef to promote natural reproduction of walleye. The project became a possibility when water levels were drawn down on the Pestigo Flowage between May and October 2012 to replace the Highway 41 bridge and complete maintenance to the dam in Peshtigo. The drawdown not only made building the spawning reef possible, but greatly reduced the cost.

Construction took place during the first weeks of August. A majority of funding was provided by Walleyes for Tomorrow ($7,000), Wisconsin Public Service ($4,000), and the Porterfield Sportsman’s Club ($3,000). Significant natural reproduction of walleye is expected once the adult population has been re-established.

– Chip Long, senior fisheries biologist, Peshtigo