Union Lake Fishing guide

No Black Crappies were sampled for the second consecutive survey since 2005. Since 1984 (n=4), trap net catch rates have varied from 0/net in 2005 and 2015 to 24.7/net in 1984 with an average of 6.5/net. Winterkill events appear to have eliminated the Black Crappie population from Union Lake and have surprisingly not rebounded like other game species in the lake. Stocking Black Crappie adults should be considered in order to reintroduce the species to Union Lake.

Bluegill

A total of 73 Bluegills were sampled with trap nets for a catch rate of 8.1/net, indicating moderate to high numbers were present. Since 1984 (n=4), catch rates have varied from 0/net in 1984 to 60.7/net in 2005 with an average of 18.6/net. Lengths ranged from 3.2 to 4.6 inches with an average of 3.8 inches. An additional 12 Bluegills ranging from 3.6 to 7.9 inches were sampled with gill nets for a catch rate of 2.4/net. Fish from both gears were 0 or 1 year old with the exception of one 8 year old fish. Overall, the Bluegill population in Union Lake is in a state of recovery from the 2013-2014 winterkill and is dominated by small, young fish.

Northern Pike

Northern Pike were sampled at an extremely high rate in 2015. A total of 140 fish were sampled with gill nets for a catch rate of 28.0/net, indicating high numbers were present. Since 1984 (n=4), catch rates have varied from 9.0/net in 1995 to 28.0/net in 2015 with an average of 16.2/net. Lengths ranged from 13.4 to 27.0 inches with an average of 19.2 inches. An additional 4 fish ranging from 14.7 to 22.3 inches were sampled with trap nets. Fish from both gears were 1 or 2 years old, with 1 year old fish making up 91% of the sample. Northern Pike numbers remain high in Union Lake despite frequent winterkills.

Yellow Perch

A total of 216 Yellow Perch were sampled with gill nets for a catch rate of 43.2/net, which was the highest ever recorded in Union Lake and indicated high numbers were present. Catch rates have increased every survey since sampling began in 1984 (n=4) with an average of 17.4/net. Lengths ranged from 5.3 to 9.8 inches with an average of 7.1 inches. An additional 54 Yellow Perch ranging from 5.6 to 7.9 inches were sampled with trap nets for a catch rate of 6.0/net. Fish from both gears ranged from 1 to 3 years old with three year-classes present. Two year old fish made up over 64% of the sample. Despite high Northern Pike numbers, Yellow Perch have continued to increase in abundance in Union Lake but small size structure limits the fishery.

Walleye

Only eight Walleyes were sampled with gill nets for a catch rate of 1.6/net, indicating low numbers were present. Since 1984 (n=4), catch rates have varied from 0/net in 1984 and 1995 to 4.0/net in 2005 with an average of 1.4/net. Lengths ranged from 12.2 to 13.7 inches with an average of 12.9 inches. An additional four Walleyes ranging from 5.7 to 12.9 inches were sampled with trap nets. Fish from both gears were 0 or 1 year old and coincide with fry stocking in 2014 and 2015. Despite regular fry stocking, the Walleye population remains low in Union Lake providing limited fishing opportunity.

Black Bullhead

A total of 336 Black Bullheads were sampled with gill nets for a catch rate of 67.2/net, which was the lowest ever recorded and indicated low to moderate numbers were present. Since 1984 (n=4), catch rates have varied from 67.2/net in 2015 to 284.0/net in 2005 with an average of 176.6/net. Lengths ranged from 4.3 to 10.7 inches with an average of 6.5 inches. An additional 63 Black Bullheads were sampled with trap nets. Despite the decrease in abundance, Black Bullheads continue to thrive in Union Lake where winterkills are common.

Common Carp

Common Carp numbers remained high in 2015. A total of 226 were sampled with gill nets for a catch rate of 45.2/net, indicating high numbers were present. Since 1984 (n=4), catch rates have varied from 27.8/net in 1995 to 56.7/net in 1984 with an average of 43.3/net. Sizes were small with over 95% less than 5.5 inches. Common Carp were also the most abundant fish sampled with trap nets with a catch rate of 44.8/net. Fish up to 27.8 inches were caught but the mean length was just 6.6 inches. Common Carp are able to repopulate Union Lake quickly following winterkill and remain a dominant member of the lake's fish community.

Other Species

Other species sampled in 2015 include Bigmouth Buffalo, Green Sunfish, hybrid sunfish, Tadpole Madtom, and White Sucker.

Water Quality Parameters

Water quality parameter measurements included secchi depth, water temperature, and dissolved oxygen readings. At the time of this survey, secchi depth was 1.9 feet, indicating poor water clarity. Water temperatures and dissolved oxygen readings throughout the water column ranged from 77.2 degrees Fahrenheit and 9.9 ppm at the surface to 76.3 degrees Fahrenheit and 6.0 ppm at 9 feet.

Shoreline property owners also play an important role in the overall health of an aquatic ecosystem, including the fish population. Natural shorelines, including vegetation, woody debris, and bottom substrates, provide valuable habitat for fish and wildlife, help maintain water quality, and reduce bank erosion. By leaving natural shorelines unaltered or restoring them to natural conditions, shoreline property owners are doing their part to maintain or improve a healthy ecosystem in the lake and protect the resource for future generations.

-Sky Wigen, Fisheries Specialist