Round Lake, Mason County, Michigan

Round Lake Improvement Board

Before Treatment
After Treatment

Round Lake is a 571-acre, closed-basin lake located in Sections 28, 29, 32, and 33 of Sheridan Township in Mason County, Michigan (T. 19N, R. 15W). The lake has one primary inlet located at the north side of the lake, and no outlet. Recent limnological surveys of the lake indicate that the lake is meso-eutrophic, with moderate turbidity, and areas of dense exotic and native aquatic macrophyte growth. In 2007, Round Lake had an extremely rigorous Eurasian Watermilfoil (EWM) infestation with over 300 of the lake’s 571 surface acres infested. During the summer of 2008, staff from RLS worked with the Little River Band of Ottawa Indians Inland Fisheries Unit in a joint study and evaluation treatment of the Eurasian Watermilfoil weevil, Euhrychiopsis lecontei. The purpose of the evaluation project was to see how the weevil responded to the Round Lake EWM population and determine if it was practical for use on a whole-lake scale. The secondary purpose was to determine if the current lepomid fishery had any detrimental impacts on the weevil survivorship. Preliminary data on the stems of treated EWM showed that there was some damage, although not enough to keep up with the fast rate of milfoil spread. A whole-lake fluridone treatment was applied in 2008 and approximately 120 acres returned in 2009. RLS staff worked with the chemical herbicide manufacturer to get a refund for the Round Lake Improvement Board and treated the remaining acreage with 2,4-D in 2009. A complete eradication was declared in 2010 and the lake remained free of Eurasian Watermilfoil in the fall of 2012. Approximately 8 acres of milfoil was found in 2013 and successfully treated with Triclopyr.