By Phil Petersen

It is hard to imagine a biological threat to the Iowa Great Lakes so damaging that modern science couldn’t fix.  That is the situation we face with Aquatic Invasive Species (AIS).  These invaders can sneak in silently and immediately begin to take over.  They have no native enemies and can grow very rapidly.  If they gain a foothold in the Iowa Great Lakes – that could negatively impact our enjoyment of the Lakes – and cause considerable economic loss to our community.  Small lakes and some invaders can be treated with chemicals, but our lakes are too large for effective chemical treatment.  For other invaders like zebra mussels, there simply is no cure.

Aquatic Invasive Species that are an immediate threat to the Iowa Great Lakes are Eurasian water milfoil, brittle naiad, and zebra mussels.  The first two are aquatic plants that have infested lakes and have found their way within 35 miles of the Iowa Great Lakes (Mill Creek and Dog Creek Lake in O’Brien County).  These plants can quickly grow out of control by creating undesirable conditions for boating, angling, and swimming.

Zebra mussels are small clams that attach to any hard surface.  When introduced to lakes and rivers, they can quickly colonize and attach to docks and hoists.  They have sharp edges that can cut swimmer’s feet and can clog the lake water intake pipes that supply our drinking water.  Five years ago, a few zebramussels were found in Clear Lake.  Today, Clear Lake docks and hoists are covered with zebra mussels and their population continues to grow.

Adult Zebra Mussel with Juvenile

With 12 major boat ramps and only three water patrol officers, we are severely limited in our boat ramp coverage.  Last summer a DNR Fisheries Bureau intern was added to help educate boaters to the threat we face from Aquatic Invasive Species, and this summer there will be three Fisheries Bureau interns assigned to the Iowa Great Lakes.

Educating and inspecting boats is hardly a waste of time.  The level of awareness and diligence of boaters has improved dramatically in recent years.  Many boaters are very aware of the threat of AIS and ways to prevent their spread. We need to remain diligent by educating boaters who are still unaware of the threat they may be carrying on their boat or trailer.


In addition to educating and informing the public, last year IGLA made a PROMISE  to its members to contribute $25 for each new $50 IGLA membership to the Water Safety Council’s fight to keep Aquatic Invasive Species out of the Iowa Great Lakes.

Last month, Phil Petersen, IGLA Executive Director, presented a $4,625 check to Gary Owen, Iowa Great Lakes Water Safety Council President.

Although our main concerns are Eurasian water milfoil and zebra mussels, we are also concerned about Asian silver carp – known as the “jumping fish. “

Bighead and silver carp are two species of Asian carp that impact Iowa’s waters. The silver carp variety can jump above the water as boats drive by, injuring boaters, tubers, and water skiers.  This species can grow to be three feet long and weigh up to sixty pounds. Both species compete with native species for food and space.

Both bighead and silver Asian carp are in the Missouri River – while bighead carp have found their way up the Little Sioux River to the Linn Grove dam  (32 miles south of the Iowa Great Lakes).


Your association has asked our Senators, Chuck Grassley and Tom Harkin to request Federal funding to assist us in the prevention of the Asian carp from migrating into the Iowa Great Lakes.