Mazaska Lake is a 672 acre lake located northeast of Shieldsville in Rice County. There is a county-owned access located off Mazaska Lake Trail on the southwest shore and a state-owned access located off Highway 21 on the southeast shore. It has a maximum depth of 50 feet, with approximately 50% of the lake classified as littoral area. It is placed in Lake Class 24, which includes other Waterville Area lakes such as Clear Lake (Waseca County), East Jefferson Lake (Le Sueur County), and French Lake (Rice County). Mazaska Lake is primarily managed for Bluegill and Black Crappie and secondarily for Largemouth Bass, Northern Pike, and Walleye. The management plan calls for an annual stocking of 15,000 Northern Pike fry in the connected wetland on the north side of the lake and 336 pounds of Walleye fingerlings stocked 2 out of 3 years. Recent Walleye dispositions include fingerlings stocked in 2011, 2012, 2014, and 2015. The lake was designated as infested in 2010 after the discovery of Eurasian Water Milfoil and annual efforts have been made to keep it and Curly-leaf Pondweed below nuisance levels. Mazaska Lake was surveyed the week of July 25, 2016 as part of a regular monitoring program conducted by the Minnesota DNR. This survey was intended to assess the fish community by deploying 9 gill nets and 12 trap nets, as well as recording water quality parameters.
A total of 124 Bluegills were sampled with trap nets for a catch rate of 10.3/net. Since 1984, catch rates have varied from 4.0/net in 1985 to 50.0/net in 1986 with an average of 21.6/net. Lengths ranged from 2.8 to 9.1 inches with an average of 4.1 inches. Larger fish were sampled at a higher rate by gill nets with a total of 36 fish averaging 7.4 inches sampled for a catch rate of 3.9/net. Approximately 50% of fish sampled with gill nets exceeded preferred length of 8.0 inches. Fish from both gears ranged from 1 to 6 years old with 6 year-classes present. Approximately 82% of the sample consisted of young 1 and 2 year old fish. On average, fish reached 6.0 inches during their third growing season, indicating fast growth relative to other area lakes. According to a 2016 creel survey, Bluegills were one of the most commonly harvested fish from Mazaska Lake with an estimated 3,355 fish averaging 8.2 inches harvested during a 10 month period from January to October. Based on the creel and survey data, the Bluegill population in Mazaska Lake was described as healthy and desirable to anglers.
Black Crappies were the most commonly sampled fish species in the gill nets with a total of 175 sampled for a catch rate of 19.4/net. Since 2002, catch rates have remained high with an average of 32.5/net. Lengths ranged from 4.5 to 13.1 inches with an average of 7.8 inches. An additional 23 fish averaging 8.4 inches were sampled with trap nets for a catch rate of 1.9/net. Fish from both gears were 1 to 8 years old with 7 year-classes present, suggesting consistent recruitment. Over half the sample was 2 years old. On average, fish reached 8.0 inches by 4 years old and 10.0 inches by 6 years old, indicating moderate to fast growth relative to other area lakes. According to a creel survey completed in 2016, Black and White Crappies were collectively the most commonly harvested species with an estimated 6,086 fish averaging 10.3 inches harvested during a 10 month period from January to October. Based on creel and survey data, Black Crappies were the single most important species to the fishery of Mazaska Lake in 2016 and were highly desirable to anglers.
Due to time constraints, a spring boat electrofishing sample targeting Largemouth Bass was not completed in 2016 and was postponed to 2017. A total of 4 Largemouth Bass were sampled with net gears. Lengths ranged from 7.8 to 15.8 inches with an average of 13.4 inches. The last electrofishing sample was conducted in 2007 and resulted in a catch rate of 67.0/hour. Those fish ranged from 6.1 to 19.4 inches with an average of 8.8 inches. The 2016 creel report offered some insight on the Largemouth Bass population in Mazaska Lake. An estimated 982 fish were caught during a 10 month period from January to October. Estimated lengths of released fish ranged from less than 5.0 inches to 20.0 inches with an average of 12.4 inches. Additional analysis of the population will be possible upon completion of the electrofishing sample scheduled for spring 2017.
A total of 76 Northern Pike were sampled with gill nets for a catch rate of 8.4/net. Northern Pike numbers have surged in the last 10 years, with an average of 7.4/net after averaging just 1.8/net from 1984 to 2002. Lengths ranged from 15.4 to 38.3 inches with an average of 22.2 inches. An additional 17 Northern Pike ranging from 13.0 to 31.0 inches were sampled with trap nets for a catch rate of 1.4/net. Fish from both gears ranged from 1 to 8 years old with 6 year-classes present. On average, fish reached 21.0 inches by 3 years old, indicating fast growth relative to other area lakes. The 2016 creel estimated that a total of 1,260 Northern Pike averaging 21.0 inches were harvested during the study period, behind only Bluegill and Crappies in numbers harvested. Northern Pike were an important member of the Mazaska Lake fishery in 2016 but high catch rates work against Walleye management and reduced stocking should be considered if Walleye numbers fall below management goals.
A total of 63 Walleyes were sampled with gill nets for a catch rate of 7.0/net. Much like the Northern Pike population, catch rates have increased in last 10 years with an average of 7.1/net after averaging just 1.3/net prior to 2007. Lengths ranged from 7.5 to 27.4 inches with an average of 15.5 inches, indicating good size structure. Fish ranged from 1 to 8 years old with 7 year-classes present. Approximately 97% of the sample came from years when Walleye fingerlings were stocked. On average, Walleyes grew at a moderate rate, reaching 15.0 inches by 4 years old. Curiously, results from the 2016 creel survey estimated that just 173 Walleyes were harvested during the 10 month study period. The majority of Walleyes caught were small (<9.0 inches) and subsequently released. Based on the gill net data, the Walleye population appeared to be in great shape and has increased in recent years to favorable numbers under the current stocking regime.
A total of 12 White Crappies were sampled with gill nets for a catch rate of 1.3/net. Catch rates have declined in recent years with an average of 2.9/net since 2007 after averaging 11.6/net before 2007. Lengths ranged from 7.7 to 12.2 inches with an average of 9.5 inches. An additional 9.5 inch White Crappie was sampled with trap nets. Fish from both gears ranged from 2 to 6 years old with 3 year-classes present. On average, fish reached 8.0 inches by 3 years old, indicating fast growth. Although less abundant than Black Crappies, White Crappies were estimated to be the third most commonly harvested species behind Black Crappie and Bluegill in the 2016 creel survey.
A total of 31 White Bass were sampled with gill nets for a catch rate of 3.4/net. Like other predator species in the lake, White Bass numbers have increased to an average of 3.5/net since 2007 after averaging just 0.4/net prior to 2007. Lengths ranged from 9.1 to 18.5 inches with an average of 15.8 inches. Fish ranged from 1 to 15 years old with 9 year-classes present. Eighty percent of White Bass were 6 years old or older suggesting few anglers target and harvest them despite trophy length (? 18.0 inches) fish being present in the population. The 2016 creel supported this assumption with only an estimated 256 White Bass caught during the study period of which approximately 80% were released.
A total of 27 Yellow Perch were sampled with gill nets for a catch rate of 3.0/net. Since 2007, predator species such as Walleye, Northern Pike, and White Bass have increased in number and the result was the decline of Yellow Perch during this time to an average of 2.4/net. Prior to 2007, catch rates averaged 16.6/net. Lengths in 2016 ranged from 5.5 to 7.8 inches with an average of 6.4 inches. The 2016 creel survey showed that anglers caught and harvested fish up to 11.5 inches which suggested gill nets may not have accurately reflected the size structure of the population. Yellow Perch are an important prey species in Mazaska Lake and low abundance could impact predator species abundance and growth.
Freshwater Drum were common in Mazaska Lake in 2016. A total of 68 fish averaging 17.4 inches were sampled with trap nets for a catch rate of 5.7/net. By weight, they accounted for approximately 61% of the trap net catch. They were also the second most commonly caught species with gill nets with a catch rate of 11.3/net. Sixty-seven percent of Freshwater Drum in the gill net sample exceeded 15.0 inches. Although undesirable to most anglers, Freshwater Drum are easily caught and provide a good fight and respectable table fare for the open-minded angler.
Bullheads have historically been rare in Mazaska Lake. In 2016, the most common species was the Yellow Bullhead. A total of 26 were sampled with gill nets for a catch rate of 2.9/net. Since 1984, catch rates have varied from 0.0/net in multiple samples and 5.0/net in 2007 with a mean of 1.5/net. Given the stability of the lake, Bullhead species will likely remain a small part of the fish community in Mazaska Lake.
A single 12.3 inch Common Carp was sampled with trap nets for a catch rate of 0.1/net. Only twice since 1984 (1984 and 1986) has the catch exceeded 1.5/net. Although destructive, Common Carp remained rare in Mazaska Lake and did not appear to negatively impact the fishery.
Other species sampled in 2016 include Bowfin, Brown Bullhead, Longnose Gar, and White Sucker.
Anglers can play an important role in maintaining or improving a fish population by practicing selective harvest. Selective harvest allows for the harvest of smaller fish for consumption, while encouraging the release of medium to large fish that may contribute to natural recruitment. This practice helps maintain balance in the fish community and provides anglers the opportunity to catch more and larger fish in the future. Additionally, smaller fish often taste better and have fewer contaminants than larger, older fish from the same water body.
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
- 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.