The north bay on Mule Lake has excessive weed growth minimizing the boat traffic and fishing in that area during the late summer. The rest of the lake appears to have experienced an increase in vegetation during the same time span but is not, as yet, a nuisance to recreational activities (e.g. swimming and fishing). Mule Lake has experienced days where tree pollen (confirmed by samples submitted to the DNR) has left a green substance in the lake which dissipated after several days.
Area Fisheries Biologist Harlan Fierstine reports that the DNR has identified aquatic vegetation along 20 transects in 2001, including completion of an “abundance” survey of the vegetation. No exotic vegetation species were identified by the DNR.
In August, 2010 an indepth vegetation survey was completed for Mule Lake. The results of that survey identified significantly more types of vegetation but did not identify any invasive species type. To get more detail follow the link below to the DNR website. Insert Mule as the lake you are trying to get more detail about and add Cass county on the next line. Then click 'get lake data'. You will see a lot of information covering Mule Lake (lake number - 11020000) as well as more in-depth data on the 2010 vegetation survey.
Several homes around Mule Lake have developed good filtering of aquatic vegetation (i.e. reeds) along portions of their shoreline. This has also provided excellent habitat for some of the fish in the lake.
Runoff issues exist at the former access on the north end of Mule Lake. This access has been closed to any trailored boats but runoff has destroyed some vegetation in the lake. This was repaired by the DNR Trails and Waterways and many lake residents late in 2008.
Links to the two vegetation surveys for Mule Lake.
2001 vegetation survey