Current Threats

The Iowa Great Lakes Association constantly monitors threats to the lakes, including but not limited to aquatic invasive species.

Our Current Identified Threats Include:

  • Eurasion watermilfoil
  • Curly-leaf pondweed
  • Bur oak blight

Our Priorities

Aquatic Invasive Species

Part of IGLA’s responsibility to uphold our mission involves remaining vigilant for threats posed by aquatic invasive species.

Top Concerns: Zebra Mussels & Eurasian Watermilfoil

Spreading to the Iowa Great Lakes from nearby Clear Lake, zebra mussels are an ongoing concern for lakes area residents and tourists. Boaters from Lake Delhi and the Mississippi River traveling to the Okoboji area also must be careful not to spread this species.

Eurasian watermilfoil threatens the lakes area due to its presence in lakes near the Twin Cities. Boaters visiting the area from this area are asked to keep boats, motors, trailers, live wells, and other equipment out of the water for five to 10 days and wash them with hot water before entering our lakes.

Potential Concerns: Asian Carp (Flying Fish)

The Silver Asian Carp, one of several Asian carp species, must be kept out of the Iowa Great Lakes, as they are a concern and potential danger to boaters. These fish have been known to jump several feet out of the water as they are startled by passing watercraft.

To keep Silver Asian Carp out of the lakes, IGLA has helped with establishing an electric fish barrier at the Lower Gar Outlet to prevent these fish from entering the lakes during periods of flooding and high water.

Enforcement Efforts

It is against Iowa law to transport or introduce an aquatic invasive species on a public road and into public waters, as well as operate any watercraft in an area marked for infestation.

In the past, the Iowa Department of Natural Resources has stationed officers at boat ramps to educate boaters and prevent the spread of aquatic invasive species.

IGLA also has a volunteer program to assist the DNR on busy weekends. Volunteers inspect boats and interview boaters to protect our lakes.

What to do if you find aquatic invasive species

Many native plants and mussels can be similar in appearance to invasive species. IGLA recommends contacting a professional to confirm identification.


Dickinson County
Conservation Board
(712) 338-2549
Spirit Lake
Fish Hatchery
(712) 336-1840