Green Lake is primarily managed for Walleye and Northern Pike. The Walleye population is currently maintained through annual fingerling stocking. Green Lake is in lake class 27 which includes moderately large, deep lakes with very hard water. To assess lake management goals and the success of the current stocking plan, Green Lake was surveyed in August of 2016.
The 2016 assessment found both Walleye size and abundance similar to the lake historic average. The Walleye catch (4.1 per gill net) was normal for the lake class and met the lake management goal. Over the last 30 years the catch rate for Walleye has averaged just under 5 per gill net. Walleye were large compared to other lakes in class 27. In the gill nets, sampled Walleye ranged from 9.7 to 27.0 inches and averaged 2.7 pounds. More than half the catch exceeded 20 inches in length. Age analysis found good growth rates. Nine year classes were present, all associated with stocking events. The 2011 year class represented 24 percent of the total catch. These 5 year old fish averaged 20.7 inches.
Northern Pike were also sampled within both the lake class norm and management goals. The 2016 catch rate (6.8 per net) was a historic high for Green Lake. Like Walleye, the Northern Pike were large compared to other lakes in class 27, averaging 3.1 pounds and 24 inches. Six year classes were present with 2012 representing nearly half the catch.
Black Crappie numbers, 26.4 per gill net, were at a historic high and remained well above the lake class norm. The average size (0.24 pounds) was on the small size compared recent catches. Crappies ranged from 3.9 to 13.7 inches in length with a 7.6 inch average.
Based on the trap net catch, both Bluegill abundance (23.4/trap net) and average size (0.18 pounds) were up slightly compared to 2012 and normal compared to similar lakes. Trap netted Bluegill averaged 6.3 inches in length and ranged from 3.0 and 9.3 inches.
Largemouth Bass were sampled by night electrofishing at a rate of 53.7 per hour, very similar to the historic high rate established in 2012. The average size of bass has increased slightly. Largemouth ranged from 8.3 to 19.5 inches with a 13.3 inch 1.5 pound average. Fifty five percent of bass were 14 inches or larger.
Yellow Perch were captured in the gill nets at a rate of 32.7 per lift. This rate was the highest since the 2002 assessment and within normal ranges for lake class 27 but below the long term average for Green Lake. Although Yellow Perch have historically been on the small side (a 6.3 inch average in this survey), they provide the primary forage for both Walleye and Northern Pike.
- Eurasian Watermilfoil
Recreational activities such as recreational boating, angling, waterfowl hunting, and diving may spread aquatic invasive species. Some aquatic invasive species can attach to boats, while others can become tangled on propellers, anchor lines, or boat trailers. Many species can survive in bilge water, ballast tanks, and motors or may hide in dirt or sand that clings to nets, buckets, anchors, and waders. Fortunately, completing simple steps can prevent the transport of aquatic invasive species.