Little Green Fisheries Survey

Summary Report – 2013

In 2013, the Department of Natural Resources conducted a fish survey of Little Green Lake in order to assess the fish community and provide some direction for the future fisheries management of this lake.   The following report is a brief summary of all activities conducted and data taken this past year.  If you have any questions, please contact: Dave Bartz, DNR Fisheries Biologist , 427 E. Tower Dr. Suite 100, Wautoma, Wisconsin, 54982. Phone: 920–787 -3016.  Scott Bunde, DNR Fisheries Technician, 427 E. Tower Dr. Suite 100, Wautoma, Wisconsin, 54982.  Phone 920–787–5683.  

Comprehensive Fish Survey – What is it?

A comprehensive fish survey is an assessment of the entire fish community in a lake.  Different survey methods are used to sample all the different fish species that inhabit a lake (including the smaller forage fish).   Fyke-netting and boomshocking are the primary fish capture methods; however, seines and other gear are also utilized.  Once fish are captured, information can be collected as it relates to species composition, abundance, size structure, age classes, growth, survival, and reproductive success.  The following report provides some of this information for most major species.

This past year the following surveys were conducted on Little Green Lake.

Spring Fyke-Netting: Larger fyke nets were used to sample the spawning population of walleye, northern pike and muskellunge.  Nets were placed in spawning locations; fish were measured, weighed, sexed and given an appropriate mark, then returned to the water.  A formula is used comparing the number of new fish caught in a net daily to the number of marked fish (recap).

Spring Boomshocking: One night of boomshocking took place in April to assess the walleye fishery and one night in early June to assess the bass and panfish fishery.

Gamefish Summary

Largemouth bass, walleye, northern pike and muskellunge are  all common gamefish in Little Green Lake.    

Largemouth Bass

Abundance: Slightly Below Average. CPE=59/hr 8 inches and larger.  

Size Structure: Good. Length Range = 6.5 - 19.5 in.  Average Length = 12.4 inches  

55% of the population larger than 8 inches was also 14 inches (legal harvestable size) or larger.  RSD14=55

Walleye

Abundance:  Good for a stocked fishery.  A total of 325 different fish were sampled in our nets. Total adult population = 1109  (2.4 walleyes/acre). We averaged 10 walleye per net/night of sampling.

Size Structure:  Good.  Length Range = 10.5 – 27.0 inches.  Average Length = 20 inches.  87% of the population was 15 inches (legal harvestable size) or larger. (PSD15=87%)

Growth and Condition:  ?????

Northern Pike

Abundance:   A total of 124 different fish were sampled.

Not enough sampled to determine a good population estimate.

Size Structure:  Fair.  Length Range = 18 – 36.5 inches.  

Average Length = 25.6 inches.  34% of the

population was 26 inches or larger                                                         (RSD26=34%) legal harvestable size.  PSD21 = 97%

Muskellunge

Abundance:   A total of 22 different fish were sampled in our nets.

Size Structure:  Length Range = 32.5 – 43.5 inches.  

Average Length = 38.0 inches.

Panfish

Bluegills, yellow perch and black crappie were all very common panfish (or prey) we caught in our survey. Other species were found in much lower abundance and made up a very small portion of the panfish/prey population.

Bluegill   

Abundance: Good.  Electrofishing Catch:  372/hour larger than 3 inches

Size Structure:  Fair.   Length Range = 3.0 – 8.0 inches.  Average Length = 5.5 inches.  (PSD = 31) 31% of bluegill captured were >6.0 inches (harvestable size).  (RSD7=17%) 17% of bluegills captured were 7.0 inches and larger in length .  Only 1 bluegill 8 inches and larger was caught.

Growth:  Slightly Above Average.  Growth rates are slightly above average with fish averaging 6.4 inches after 4 years of life.  Statewide average is 6.0 inches after 4 years.

Yellow Perch   

Abundance: High.  Fyke Net Catch =  2,706 were caught  (75/net)

Size Structure:  Poor.   Length Range = 5.0 – 10.0 inches.  Average Length = 6.3 inches.  (PSD = 8%) 8% of yellow perch captured were >8.0 inches.  

Growth:  Above Average.  Growth rates are above average with fish averaging 8.1 inches after 4 years of life.  Statewide average is 7.0 inches after 4 years.

Black Crappie

Abundance:  We sampled 327 fish in our nets.

Size Structure:  Length Range = 5.5 – 11.0 inches

Average length = 9.5 inches

Growth:  Slightly Above Average.  Growth rates are a little above average with most crappies attaining quality size (8 inches) after their 3rd year of life.

 Other Panfish and Forage Species

Other panfish and forage species captured during the survey include:  Green sunfish, white sucker, brown bullhead, black bullhead, pumpkinseed, rock bass, common carp and golden shiners.

PSD =(number of fish  minimum quality length  number of fish  minimum stock length)  100

RSD =(number of fish  specified length  number of fish  minimum stock length)  100

                                                     Stock Length     Quality Length

                    Northern Pike             14 inches              21 inches

                    Largemouth Bass         8 inches              12 inches

                     Bluegill                        3 inches               6 inches

CPE (Catch Per unit Effort) - The number of a given species caught during a defined sampling effort.  When shocking the shoreline of a lake we keep track of how much time it takes.  We then count the number of a certain species we caught during that time and convert to a number caught per hour of shocking.  These catch rates are then compared in future surveys.