Oct. 3, 2014

Invasive, sharp-shelled mollusk discovered in Management Park cove

TOPEKA– The Kansas Department of Wildlife, Parks and Tourism (KDWPT) has confirmed the presence of invasive zebra mussels in Pomona Reservoir in Osage County. A small adult group was discovered on a single rock by U.S. Army Corps of Engineers (USACE) staff on September 23 in Management Park cove near the south end of the dam. KDWPT staff found more zebra mussels the next day. KDWPT is sampling other parts of the lake to determine if the population has spread. Twenty-three Kansas lakes now have confirmed zebra mussel populations. Other reservoirs in northeast Kansas with zebra mussel infestations include Milford, Perry, John Redmond, Clinton and Melvern.   

Pomona Reservoir covers approximately 4,000 acres and is located 24 miles south of Topeka. It is managed by the USACE, and KDWPT manages the fishery. The lake, completed in 1963, is home to Pomona State Park and several USACE parks. It is a popular destination for fishing, camping, swimming, hiking, and a variety of boating and other water-related activities.          

USACE and KDWPT officials stress that there is no known method to completely rid a lake of zebra mussels. If the population appears to be limited to Management Cove, officials may attempt to treat the cove within the next week to kill as many of the mussels as possible to slow their spread. The cove and boat ramp will be closed for at least 72 hours if the chemical is used. Generally, fish will move out of an area where treatments are applied. As a result, officials don’t expect a large fish kill, though there may be some mortality among fish remaining in the cove.  

Officials emphasize that everyone using the lake plays a key role in stemming the spread of mussels to uninfested lakes. “This situation shows how important it is for boaters, anglers, swimmers and skiers to be aware of aquatic nuisance species (ANS) and to take precautions to prevent their spread,” said Jessica Howell, KDWPT Aquatic Nuisance Species Coordinator.

Prevention is the best way to avoid spreading ANS. They often travel by “hitchhiking” with unsuspecting lake-goers. “Always clean, drain, and dry boats and other equipment and don’t transfer lake water or live fish to another body of water. This can help stop the spread of not only zebra mussels, but most aquatic nuisance species that may be present,” Howell said. 

The lake will be added to the list of ANS-designated waters in Kansas, and notices will be posted at various locations around the reservoir. The sharp-shelled zebra mussels attach to solid objects, so lake-goers should be careful when handling mussel-encrusted objects and when grabbing an underwater object when they can’t see what their hands may be grasping. Visitors should protect their feet when walking on underwater or shoreline rocks.     

Zebra mussels are just one of the non-native aquatic species that threaten our waters and native wildlife. After using any body of water, people must remember to follow regulations and precautions that will prevent their spread:

  • Clean, drain and dry boats and equipment between uses
  • Use wild-caught bait only in the lake or pool where it was caught
  • Do not move live fish from waters infested with zebra mussels or other aquatic nuisance species
  • Drain livewells and bilges and remove drain plugs from all vessels prior to transport from any Kansas water on a public highway.

For more information about aquatic nuisance species in Kansas, report a possible ANS, or see a list of ANS-designated waters, visit ProtectKSWaters.org.


Zebra mussels are dime-sized mollusks with striped, sharp-edged, two-part shells. They can produce huge populations in a short time and do not require a host fish to reproduce. A large female zebra mussel can produce 1 million eggs, and then fertilized eggs develop into microscopic veligers that are invisible to the naked eye. Veligers drift in the water for at least two weeks before they settle out as young mussels which quickly grow to adult size and reproduce within a few months.

After settling, zebra mussels develop byssal threads that attach their shells to submerged hard surfaces such as rocks, piers, and flooded timber. They also attach to pipes, water intake structures, boat hulls, propellers, and submerged parts of outboard motors. As populations increase, they can clog intake pipes and prevent water treatment and electrical generating plants from drawing water. In 2012, two Kansas communities, Council Grove and Osage City, experienced temporary water shortages from zebra mussel infestations before water intake structures could be cleaned up. Removing large numbers of zebra mussels to ensure adequate water flow can be labor-intensive and costly.

Zebra mussels are native to the Black and Caspian seas of western Asia and eastern Europe and   were spread around the world in the ballast water of cargo ships. They were discovered in Lake St. Clair and the Detroit River in 1988 and quickly spread throughout the Great Lakes and other rivers including the Mississippi, Illinois, Ohio, Tennessee, Arkansas and Hudson. They were first discovered in Kansas in 2003 at El Dorado Reservoir. Despite public education efforts to alert boaters about the dangers of zebra mussels and how to prevent spreading them, the species continues to show up in new lakes every year. Moving water in boats and bait buckets has been identified as a likely vector.

For information about Pomona State Park, visit www.ksoutdoors.com/Pomona-State-Park

For information about Pomona Reservoir and USACE campgrounds, visit http://www.nwk.usace.army.mil/Locations/DistrictLakes/PomonaLake.aspx