FOR IMMEDIATE RELEASE: Monday, November 24, 2014

CONTACT: Emily Kiel at Emily.Kiel@state.sd.us  

Single Adult Zebra Mussel Discovered at Lewis and Clark Lake

PIERRE, S.D. – On Nov. 14, 2014, a single adult zebra mussel was discovered at the Midway boat ramp on Lewis and Clark Lake near Yankton. As a result of the discovery, the South Dakota Game, Fish and Parks (GFP) has classified the lake as ‘suspect’ for contamination by zebra mussels.

“Inspections of 11 boat docks and shorelines yielded no additional zebra mussels in or near the lake,” stated John Lott, GFP chief administrator of aquatic resources. “The hulls of some boats being stored for the winter were also inspected and no mussels were found, though many boats are power-washed prior to storage.”

Lewis and Clark Lake is a U.S. Army Corps of Engineers project and the fishery is jointly managed by the states of South Dakota and Nebraska. South Dakota aquatic resource staff will continue to work in partnership with Nebraska Game and Parks Commission staff to monitor the lake and determine appropriate steps to protect the important aquatic resources of both states.

“The Nebraska Game and Parks Commission water samples from this summer were negative for the presence of larval-stage zebra mussels; which are called veligers. Finding other adults or veligers in the lake during the next three years would result in the classification being changed from ‘suspect’ to ‘positive,’” stated Lott.

Zebra mussels are a small invasive mollusk (clam) that originated in Eastern Europe and first arrived in the U.S. in the mid-1980s. Although usually less than an inch in size as adults, they can rapidly spread under the right conditions. It is not known if those conditions exist in Lewis and Clark Lake at this time. Zebra mussels are closely related to quagga mussels. Quagga mussel veligers were discovered in Angostura Reservoir (Fall River County) earlier this fall.

Current aquatic invasive species (AIS) management efforts in South Dakota include monitoring for AIS in selected waters across the state and balancing information and education efforts with regulations to prevent new introductions and slow the spread of existing AIS populations.

“The documentation of quagga mussel veligers in Angostura Reservoir and a single zebra mussel in Lewis and Clark Lake will result in a detailed evaluation of how GFP will manage AIS in the future. Currently, we are evaluating multiple management options including restricting the movement of water among lakes, requiring all drain plugs to be removed during watercraft transit, requiring boat inspections and increasing outreach efforts. Our goal is to determine which options will have meaningful results in stopping or slowing the spread of AIS in our state,” concluded Lott.

For more information on AIS and how to reduce the spread, please visit sdleastwanted.com.

-GFP-