Thinleaf cattail

For all the great reasons that make the Glen Lake/ Crystal River Watershed so beautiful and unique, we do need to set the record straight – our watershed is NOT free of invasive species.

Invasive species are those living things that are often introduced and spread through recreational boating and angling activities with long
lasting negative impacts. They often out-compete our native species for space and resources.

Some of the invasive species the Glen Lake Association is aware of include shoreline plants; Coltsfoot, Purple Loosestrife, Yellow Iris, Phragmites, and Thin Leaf Cattail. Animal species include Mute Swan, Japanese Coi, European Starlings, and Zebra Mussels. Aquatic species include Curly-Leaf Pondweed.  

For each species listed above, the GLA has a working plan to eradicate and/or control the species so they do not spread and evolve into costly
control programs. The Yellow Iris is aggressively taking hold in the Fisher Lakes and has the GLA concerned that riparians see it as a
beautiful plant and tend to not want to remove it. People who see the Mute Swan also are enamored by their grace and beauty, not aware of
their aggressive behavior to humans and other native species, such as the Trumpeter Swan.

In addition, the Japanese Coi –a pet fish that likely came from someone’s artificial pond– was first discovered in Little Glen three years
ago. Now it’s been spotted on several occasions in Big Glen this past year.  

The GLA Boat Wash is the best management plan to prevent invasive species from entering our watershed. If you have seen any of the
above species or have encountered invasives not on this list, please contact the GLA to come and validate your findings.

Contact Tricia Denton at or call 231 313-0359.