dave bartz, wi dnr fisheries biologist, green lake fish survey 2011

Big Green Lake Fish Survey - 2011

ObjectivesObjectives Sample Coolwater FisheriesSample Coolwater Fisheries

Spring Fyke netting and ElectrofishingSpring Fyke netting and Electrofishing Walleye, Northern Pike, Bass sp. and panfishWalleye, Northern Pike, Bass sp. and panfish

Catch Rates/Population DensityCatch Rates/Population Density Population Age Structure and Growth RatesPopulation Age Structure and Growth Rates

Fall ElectrofishingFall Electrofishing Walleye RecruitmentWalleye Recruitment

Sample Coldwater FisheriesSample Coldwater Fisheries Fall Gill Netting, Fyke Netting and ShockingFall Gill Netting, Fyke Netting and Shocking

Lake Trout, Brown Trout and Cisco Lake Trout, Brown Trout and Cisco Catch Rates/Population Density Catch Rates/Population Density

Carp?Carp?

Fyke Net Lead

Set Fyke Net

Set Net ready to run

Sex determination on Northern Pike

All fish sexed and measured to nearest tenth of an inch Weights and age samples taken on subsample

Green Lake Musky

2500 stocked annually since 2004

Black Crappie

Walleye Length Frequency

0

20

40

60

80

100

120

140

160

180

12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28

Inch Class

Num

ber

Males

Females

Walleye Length - Percent Frequency

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

40.0

12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28

Inch Class

Perc

ent

Males

Females

Northern Pike Length Frequency

0

5

10

15

20

25

15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31

Inch Class

Num

ber

males

females

Northern Pike Length - Percent Frequency

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31

Inch Class

Perc

ent

males

Females

Boomshocker

Age StructuresAge StructuresDorsal Spines

Scales

Walleye - 94 surveyWalleye - 94 survey

Low density populationLow density population Recruitment problemsRecruitment problems

habitat losshabitat loss predation/competitionpredation/competition cool water temperaturescool water temperatures

Increased interest in stockingIncreased interest in stocking Concern over geneticsConcern over genetics

Mixing OTC Solution for marking fry

Gill NettingGill Netting

Net locations are historical sitesNet locations are historical sites Target species are Lake Trout and Target species are Lake Trout and

CiscoCisco Catch rate comparisonsCatch rate comparisons Size structure comparisonsSize structure comparisons New aging techniques New aging techniques

Stocking 1980-PresentStocking 1980-Present

Quotas increased 1980-82Quotas increased 1980-82 Increased recruitment by 1984Increased recruitment by 1984 Disease problems 1987-89 - No stockingDisease problems 1987-89 - No stocking Stocking quotas raised to 50,000 in 1991Stocking quotas raised to 50,000 in 1991 Presently quotas back to 25,000Presently quotas back to 25,000 Average 30,736 since 1992Average 30,736 since 1992 VHS concerns have affected availabilityVHS concerns have affected availability

Cisco

Seeforellen Brown Trout

CarpCarp

First planted in 1882First planted in 1882 Full scale removal efforts by 1930’sFull scale removal efforts by 1930’s Carp trap at County A in 1950’s-60’sCarp trap at County A in 1950’s-60’s State rough fish crews 1950’s-60’sState rough fish crews 1950’s-60’s Commercial removal during the 80’sCommercial removal during the 80’s Carp trap at County K – 1992 Carp trap at County K – 1992

replaced by barrier in 2009replaced by barrier in 2009 Commercial contractsCommercial contracts

SummarySummary

Fish Populations are constantly Fish Populations are constantly changingchanging

What can be done to help improve?What can be done to help improve? Habitat Protection and RestorationHabitat Protection and Restoration Water Quality IssuesWater Quality Issues Aquatic InvasivesAquatic Invasives

PlantsPlants AnimalsAnimals Disease - VHS?Disease - VHS?

Goal is to Improve Fish Populations and Fishing

Thank YouThank You

Questions ?