Survey Method
Black Otter Lake was sampled according to spring netting (SNI) protocols as outlined in the statewide lake assessment protocol. The primary objective for this sampling period is to count and measure adult northern pike. However, we also used this sampling period to asses other species including yellow perch, largemouth bass, bluegill, and black crappie.
Fyke nets were deployed in areas of the lake that contained spawning habitat or were likely travel areas for northern pike. All newly captured northern pike were marked with anchor (Floy) tags in the dorsal fin. All captured game and panfish were identified to species and measured for length. A subsample of fish were weighed and age structures (anal spines) were collected from northern pike for age and growth analysis.
Fish metrics used to describe fish populations include total abundance (mark and recapture popu-lation estimate for northern pike), proportional stock density, catch per effort, length frequency distribution, and mean length at age for northern pike.
2008 Spring Netting (SNI) Summary Report
Black Otter Lake
Outagamie County (WBIC 315600)
Fish Metric Descriptions
Catch per unit effort (CPUE) is an index used to measure fish population relative abundance which simply refers to the number of fish captured per unit of distance or time. For netting surveys we typically quantify CPUE by the number and size of fish per net night. CPUE indexes are compared to statewide data by percentiles and within lake trends. For example, if a CPUE is in the 90th percentile, it is higher than 90% of the other CPUEs in the state.
Total abundance is a metric that describes population size and is estimated by mark and recapture. In our study, during spring netting, a portion of the northern pike pop-ulation is captured, marked (with a partial fin clip), and released. During follow-up surveys, another portion is captured and the number of marked individuals within the sample is counted. The proportion of marked and unmarked fish is used to estimate the size of the population.
Proportional Stock Density (PSD) is an index used to describe size structure of fish. It is calculated by dividing the number of quality size fish by the number of stock size fish for a given species. PSD values in the 30 to 50 percent range generally describe a balanced fish population. PSD indexes are compared to statewide data by percen-tile and to within lake trends.
Length frequency is a graphical representation of the number of fish captured by either 1/2 inch or one inch size intervals. Smaller fish (or younger age classes) may not always be represented in the length frequency due to different habitat usage or gear sampling limitations.
Introduction and Survey Objectives
In 2008, the Department of Natural Resources conducted a fyke netting survey of Black Otter Lake to assess the fisheries community prior to a draw down to control invasive aquatic plants. Primary sampling objectives were to characterize species composition, rela-tive abundance, and size structure of target fish species. The following report is a brief summary of the survey results Acres: 75 Shoreline Miles: 3.2 Maximum Depth (feet): 9 Lake Type: Drainage (impoundment) Public Access: 1Public Landing Regulations: Statewide default regulations
Ryan Koenigs—Fisheries Biologist Aaron O’Connell - Fisheries Technician
Wisconsin Dept. of Natural Resources
625 E. County Rd. Y, Suite 700 Oshkosh, WI 54901
Ryan Koenigs Phone: 920-303-5450 E-mail: [email protected]
WISCONSIN DNR CONTACT INFO.
Survey Information
Site location Survey Dates Water Temp.
(F) Target Species
No. of Nets
Gear Net Nights
Black Otter Lake 4/11/2008 - 4/15/2008 38 - 40.4 Northern Pike, Panfish 5 Fyke Net 19
Relative Abundance (Catch per Unit Effort)
Species Total No. Captured
CPUE (no per net night)
Statewide Percentile
Rank
Abundance Rating
2016
BLACK CRAPPIE 106 5.6 63rd Moderate
BLUEGILL 934 49.2 84th High
LARGEMOUTH BASS 80 4.2 95th Very High
NORTHERN PIKE 255 13.4 95th Very High
PUMPKINSEED 45 2.4 62nd Moderate
YELLOW PERCH 41 2.2 55th Moderate
BULLHEAD 61 3.2 - -
WHITE SUCKER 1 0.05 - -
CHANNEL CATFISH 1 0.05 - -
GOLDEN SHINER 48 2.5 - -
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Total Abundance (Mark and Recapture Population Estimate
Species Number Marked
(Netting)
Number Sampling
Events (Netting)
No. Recap-tures
(Netting)
Schnabel Population Estimate
(95%)
No per Acre
Abundance Rating
NORTHERN PIKE
185 5 69 313
(257 - 400) 4.2 Moderate
Size Structure Metrics
Species Total Average Length
(Inches) Length Range
(Inches) Stock and Quality
Size (inches) Stock No Quality No PSD Percentile Rank Size Rating
LARGEMOUTH BASS 80 13.1 6.1 19.0 8.0 and 12.0 74 52 70% 46th Moderate
NORTHERN PIKE 255 22.2 12.0 - 35.6 14.0 and 21.0 185 120 65% 75th Moderate-High
Black Otter Lake (WBIC 315600) - Summary Report Continued
Gamefish Summary Page 2
Gamefish Summary Northern Pike
Relative abundance metrics were at very high levels relative to the statewide average, while the population estimate of 4.2 adult northern pike/acre is mod-erate relative to statewide averages. The size structure observed within the population was at moderate levels compared to statewide data, with the aver-age pike measuring 22.2”. Overall, 9.7% of the fish captured were larger than 26”. Age and growth data indicated that both the male (76.5%) and female (88.5%) populations were dominated by 3 year old fish. Further, growth data indicated that females have the growth potential to exceed 36” (largest fish collected was 35.6”), while the average male is estimated to reach a maximum length of 25.5”.
Largemouth Bass
Largemouth bass were captured at very high catch rates relative to statewide data and size structure metrics indicated moderate-high size structure. 52.5% of the largemouth bass collected during the survey were larger than the 14” minimum length limit, which is an indication of good growth and a quality size structure. The largemouth bass, and northern pike, benefit from abundant forage in the form of small panfish.
White Clay Lake (WBIC 326400) - Summary Report Continued
Gamefish Summary
Black Otter Lake (WBIC 315600) - Summary Report Continued
Panfish Summary
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Size Structure Metrics
Species Total Average Length
(Inches) Stock and Quality
Size (inches) Stock No Quality No PSD Percentile Rank Size Rating
BLUEGILL 934 6.0 3.0 and 6.0 inches 838 447 53% 44rth Moderate
BLACK CRAPPIE 106 7.0 5.0 and 8.0 inches 96 27 28% 22nd Low
PUMPKINSEED 45 5.4 3.0 and 8.0 inches 43 9 21% 24th Low
Length Range (Inches)
2.7– 8.8
4.5 - 11.3
3.9 - 6.9
YELLOW PERCH 41 9.1 6.1 - 11.7 5.0 and 8.0 inches 41 31 76% 92nd Very High
Panfish Summary Bluegill
Bluegill catch rates were high relative to statewide data, while size structure metrics were moderate relative to statewide data. The largest bluegill captured was 8.8”, which demonstrates growth potential, but overall the blue-gill population was dominated (67.7%) by fish <6.5”.
Black Crappie
Black crappie catch rates were moderate when compared to statewide data, but a poor size structure was observed. There were a number of crappie larger than 10” captured in the sample, but the majority of the fish were under 8” in length (71.7%). It appears that there is a relatively strong year class of young crappie that hopefully will provide quality fishing opportunities in the future.
Yellow Perch
Catch rates of yellow perch were moderate relative to statewide data and a quality size structure was observed. There was a wide-spread of lengths within the yellow perch sample with a strong contribution of 9.0-9.4” fish.
Stocking History
Species Year Age Mean Length Number Stocked
BLUEGILL 1972 ADULT 5 1440
BLUEGILL 1973 ADULT 5 5146
BLUEGILL 1974 ADULT 3 3105
BLUEGILL 1977 ADULT ‐ 2200
BLUEGILL 1979 ADULT ‐ 1800
BLUEGILL 1985 ADULT 3 900
BLUEGILL 1990 YEARLING 4 720
BLUEGILL X UNKNOWN 1991 ADULT (BROODSTOCK) 5 17
LARGEMOUTH BASS 1972 FINGERLING 1 5000
LARGEMOUTH BASS 1973 FINGERLING 3 7500
LARGEMOUTH BASS 1976 FINGERLING 3 5000
LARGEMOUTH BASS 1977 FINGERLING 3 5000
LARGEMOUTH BASS 1978 FINGERLING 3 4000
LARGEMOUTH BASS 1978 FINGERLING 1 1000
LARGEMOUTH BASS 1990 YEARLING 9 50
LARGEMOUTH BASS 1991 FINGERLING 2.8 750
LARGEMOUTH BASS 1992 FINGERLING 4.6 650
LARGEMOUTH BASS 1993 FINGERLING 1 14000
LARGEMOUTH BASS 1994 FINGERLING 1.9 40950
NORTHERN PIKE 1972 FRY 1 165000
NORTHERN PIKE 1976 FRY ‐ 100000
NORTHERN PIKE 1977 FRY ‐ 100000
NORTHERN PIKE 1978 FRY ‐ 100000
LARGEMOUTH BASS 1997 LARGE FINGERLING 6 100
LARGEMOUTH BASS 1998 SMALL FINGERLING 2 2000
LARGEMOUTH BASS 1995 FINGERLING 3.9 6000
NORTHERN PIKE 1991 FINGERLING 7.9 400
NORTHERN PIKE 1992 FINGERLING 8 150
NORTHERN PIKE 1994 FINGERLING 1.5 20000
YELLOW PERCH 1973 ADULT 5 2322
YELLOW PERCH 1977 YEARLING ‐ 5000
YELLOW PERCH 1978 ADULT ‐ 2800
YELLOW PERCH 1979 YEARLING ‐ 5000
YELLOW PERCH 1990 ADULT 8 30
YELLOW PERCH 1998 YEARLING 7 6500
YELLOW PERCH 2002 YEARLING 6 3200
Black Otter Lake (WBIC 315600 - Summary Report Continued
Management Options and other Information
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