The Sauk River Chain of Lakes is located in south central Minnesota, near the city of Richmond. A dam on the Sauk River at Cold Spring allows users to access over 3,200 acres by water. The Sauk River drains a large portion of central Minnesota before flowing through the chain of lakes. Combined with drainage from the Long Lake sub-watershed to the south, the total watershed of the chain is nearly 600,000 acres. Although non-point source pollution (agricultural run-off) continues to be a concern, some major contributors of nutrient loading (such as municipal wastewater discharge) were greatly reduced in the 1980's and 1990's. Efforts continue to be made to address existing nonpoint pollution sources, but most of the lakes in the chain remain classified as hypereutrophic (nutrient-rich).
Most of the Sauk River Chain was re-surveyed in 2013, with the exception of Horseshoe and Cedar Island which were surveyed prior to the introduction of Muskellunge in 2011. Netting results from the river portion of the chain (lakes downstream of Cedar Island Lake - Zumwalde, Great Northern, Krays, Knaus, Schneider, and Bolfing) were similar and were combined for this summary.
Largemouth Bass were assessed in the spring by day-time electrofishing. Portions of Zumwalde, Great Northern, Krays, Knaus, Schneider, and Bolfing were sampled. Catch rates were down from previous surveys and were less than half the rate typically observed in other lakes in the Montrose management area. Cooler than average spring water temperatures likely affected seasonal patterns as most bass sampled came from deeper water making it much harder to effectively sample bass with traditional electrofishing gear. Largemouth Bass ranged in length from 6.1 to 19.5 inches with a mean length of 13.3 inches. Of the catchable size Largemouth Bass, 83% were greater than 12 inches and 49% were greater than 15 inches. Smallmouth Bass also comprised 13% of the bass sampled by electrofishing.
The catch rate of Northern Pike in 2013 was within the range of expected values for lakes similar to the Sauk River Chain, and similar to the 2003 survey. Since 1980, catch rates of Northern Pike in these lakes have been relatively stable. Northern Pike ranged in length from 17.8 to 35.6 inches with an average length and weight of 23.1 inches and 2.2 pounds.
From 2000 to 2007, the Walleye population was supported through fry stocking by the Sauk River Chain of Lake's Association. Nearby Cedar Island and Horseshoe Lakes are also biennially stocked with fry by the DNR, and migration among the lakes was verified by fall electrofishing in 2011 when fingerings were sampled throughout the eastern portion of the chain where none were stocked. Fry stocking in 2009 on Horseshoe and Cedar Island Lakes was very successful and the catch throughout the Sauk River Chain was dominated by this year class. The Walleye catch rate in 2013 was within the range expected for the Sauk River Chain, and similar to the 2003 survey. Walleye ranged in length from 13.1 to 25.6 inches and averaged 17.6 inches and 2.0 pounds. Walleye growth was average when compared to statewide data and grew to a length of 16.3 inches by age 4.
Yellow Perch catch rates increased slightly from 2003 to 2013 survey but remained below the expected range for similar lakes. Yellow Perch ranged in length from 5.4 to 9.3 inches and averaged 6.8 inches and 0.16 pounds. Prior to the 2003 survey, catch rates of Yellow Perch were significantly higher on these lakes.
Channel Catfish were introduced into the chain in 1976 and have become well established. In the 1985 and 1990 surveys, Channel Catfish were sampled at relatively low rates in the river portion of the chain, but the population appeared to expand in the early 1990s. Schneider Lake has been an exception to this trend, as the catch rate has remained low. Schneider Lake has clearer water, more submerged vegetation, is less river-like, and is probably less favorable for Channel Catfish. Channel Catfish ranged in length from 10.9 to 25.8 inches with a mean length and weight of 17.6 inches and 1.7 pounds. Growth rates of Channel Catfish were relatively slow as fish grew to an average length of 17.7 inches in eight years.
The Black Crappie catch was unchanged from 2003 in the eastern portion of the chain of lakes and generally exceeded the expected range for these types of lakes. Black Crappie ranged in length from 2.3 to 13.0 inches with an average length and weight of 8.4 inches and 0.36 pounds.
The Bluegill catch in 2013 was very similar to 2003, and remained at the low end of the range of expected values for similar lakes. Bluegill ranged in length from 2.8 to 9.4 inches with an average length and weight of 5.6 inches and 0.24 pounds.
One Muskellunge, a two year old 24.6 inch female, was sampled in Knaus Lake during the 2013 survey. This fish was stocked in the fall of 2011 as a fingerling and was likely between 11 and 13 inches at the time of stocking. This suggests that Muskellunge have the potential for excellent growth in the Horseshoe Chain of Lakes. All muskie fingerlings stocked in the Horseshoe Chain in the fall of 2013 were implanted with an electronic tag under the dorsal fin which will allow the DNR to track the individual growth of fish in the future and is part of a research project to assess the success of the muskie introduction to the Horseshoe Chain of Lakes.
Other species sampled during the 2013 survey included: hybrid and Pumpkinseed sunfish, Bigmouth Buffalo, Bowfin, Yellow, Brown, and Black bullhead, Golden, Greater, Shorthead, and Silver redhorse, White Sucker, and Common Carp.