Eagle Lake is a 120-acre lake located near the City of Mountain Lake in Cottonwood County. Eagle Lake averages 6.0 ft. deep and has a maximum depth of 8.0 ft. Eagle Lake suffered a severe winterkill during the winter of 2013-2014. A winterkill assessment done in April only captured black bullheads at a rate of 121.8 per trap net. The winter of 2013-2014 proved to be harsh on many area lakes, as the ice was snow covered for much of the winter and ice thickness was consistently over 30 inches, preventing sunlight penetration for photosynthesis. Eagle Lake is managed primarily for yellow perch and secondarily for walleye and northern pike. Because sport fish populations were decimated from winterkill, adult yellow perch, adult walleye, northern pike fingerlings, and walleye fingerlings were stocked in 2014. A population assessment was conducted during the week of August 13, 2014 using one gill net and eight trap nets to gauge the success of the stockings.
Historically, yellow perch have been extremely abundant in Eagle Lake with catch rates of 256.0 per gill net in 1995 and 127.0 per gill net in 2008. Following the winterkill and subsequent restocking in 2014, yellow perch were captured at a rate of 26.0 per gill net, which is below the long term average of 136.3 per gill net, but slightly above the expected range of catch rates for similar lakes. This indicates that there were plenty of adult yellow perch in the lake to reproduce and bolster the population. Lengths of yellow perch ranged from 5.4 to 9.9 inches and averaged 8.1 inches. Yellow perch were plump, indicating that prey is abundant in Eagle Lake. The yellow perch population appears to be recovering from the winterkill in 2013-2014, and should have a decent population of yellow perch in a couple of years.
Management of northern pike in Eagle Lake began in 2004, which marks the first stocking of northern pike fingerlings in this system, in recent history. Additionally, northern pike fingerlings were stocked in 2007, 2010, 2011, and 2014. Despite stocking efforts, northern pike had not been sampled in Eagle Lake until the 2014 survey, when they were captured at a rate of 3.0 per gill net and 0.9 per trap net. The gill net catch rate of 3.0 is within the expected range of catch rates for similar lakes. Northern pike sampled in gill nets and trap nets ranged from 8.7 to 11.4 inches and averaged around 10 inches, and are likely the northern pike fingerlings that were stocked in mid-June 2014. The northern pike population should be on its way to recovery barring any setbacks during the winter of 2014-2015.
Walleye have been abundant in the two surveys that have been conducted since walleye management began in Eagle Lake in 1999 (initial fry stocking). In 2008, walleye were captured at a rate of 27.0 per gill net. In 2014, the catch rate of walleyes was slightly higher at 29.0 per gill net, which is higher than expected catch rates for similar lakes. The walleyes that were captured in the gill net were likely from the stocking of adult walleyes that occurred in May 2014. Walleyes ranged in length from 12.4 to 19.5 inches and averaged 14.9 inches. Walleye were plump, indicating that there is plenty of food available in Eagle Lake. Walleyes will continue to be stocked every third year to maintain the walleye population. The next walleye fry stocking will occur in 2015.
Black bullhead abundance has been highly variable since 1995, as gill net catch rates went from 26.0 per gill net in 1995 to 251.0 per gill net in 2008 to 99.0 per gill net in 2014, and as trap net catch rates went from 109.4 per trap net in 1995 to 5.0 per trap net in 2008 to 133.5 per trap net in 2014. The 2014 gill net catch rate was within the expected range of catch rates for similar lakes. The 2014 trap net catch rate slightly exceeded what would be expected in similar lakes. Black bullhead captured in the trap nets ranged from 4.7 to 11.9 inches and averaged 6.6 inches.
Bluegill (7.8 per trap net) and black crappie (1.5 per trap net) were sampled in the 2008 survey, but were not sampled in the 2014 survey. These species are vulnerable to low dissolved oxygen levels and likely did not survive through the winter of 2013-2014. Additionally, yellow bullheads were sampled in 2008 (0.8 per trap net), but were not detected in 2014.
Plants in the water and at the water's edge provide habitat, prevent erosion, and absorb excess nutrients. Shrubs, trees, and woody debris such as fallen trees or limbs provide good habitat both above and below the water and should be left in place. By leaving a buffer strip of natural vegetation along the shoreline, property owners can reduce erosion, help maintain or improve water quality, and provide habitat and travel corridors for wildlife.
Best management practices within the watershed (no-till farming, cover crops, buffer strips, targeted fertilizer application, reduced or metered tiling) would help reduce nutrients entering the lake. High nutrient and sediment input can cause algae blooms and reduce overall water quality. Any improvements in the watershed are likely to have positive impacts on the fishery.
Prepared by Jonah Dagel