Zebra Mussels in South Carolina: The Potential Risk of Infestation by Steven de Kozlowski and Chris Page S.C. Department of Natural Resources and Jack Whetstone Clemson University S.C. Sea Grant Consortium This report was initiated by the South Carolina Zebra Mussel Task Force and supported by CLEMSON South Carolina Department of Natural Resources E X T E N S I O N South Carolina Sea Grant Consortium and Clemson University Jointly funded by the South Carolina Department of Natural Resources, the South Carolina Sea Grant Consortium and Clemson University 2002 The South Carolina Department of Natural Resources prohibits discrimination on the basis of race, color, gender, national origin, religion, disability or age. Direct all inquiries to the Office of Human Resources, PO Box 167, Columbia, SC 29202. Total Copies - 300 • Total Cost - $2,417 • Cost per Copy - $8.00 02WR3607 SOUTH CAROLINA ZEBRA MUSSEL TASK FORCE Steve de Kozlowski - S.C. Department of Natural Resources, Co-chair Rick DeVoe - S.C. Sea Grant Consortium, Co-chair Butch Younginer - S.C. Department of Health & Environmental Control Reese Edwards - S.C. Governor’s Office John Inabinet - S.C. Public Service Authority Larry Setzler - S.C. Ports Authority Robin Socha - U.S. Army Corps of Engineers (Charleston) Bill Bailey - U.S. Army Corps of Engineers (Savannah) Ed EuDaly - U.S. Fish and Wildlife Service Chuck Jennings - U.S. Coast Guard Cam Ferguson - Greenville Water System Andrew Fairey - Charleston Commissioners of Public Works Eddie Dearybury - Spartanburg Water System Bud Summers - City of Columbia Arnie Gnilka - Duke Power Company John Pearrow - S.C. Electric and Gas Company Michael Swing - Carolina Power and Light Company S.C. Rural Water Association S.C. Chamber of Commerce, Technical Committee Zebra Mussels in South Carolina: The Potential Risk of Infestation by Steven de Kozlowski and Chris Page S.C. Department of Natural Resources and Jack Whetstone Clemson University S.C. Sea Grant Consortium This report was initiated by the South Carolina Zebra Mussel Task Force and supported by South Carolina Department of Natural Resources and South Carolina Sea Grant Consortium January 2002 TABLE OF CONTENTS Introduction:..................................................................................................... 1 Zebra Mussel Biology and Dispersal:.............................................................. 2 Impacts of Zebra Mussel Infestations: ............................................................. 4 Assessment Method: ........................................................................................ 6 Water Quality Parameters and Associated Suitability Criteria .................... 6 Dissolved Oxygen ............................................................................. 6 Temperature....................................................................................... 7 pH ..................................................................................................... 7 Calcium ............................................................................................. 7 Salinity .............................................................................................. 8 Results and Discussion .................................................................................... 9 Potential for Colonization............................................................................ 9 Potential Sources of Introduction ............................................................. 10 Recommendations.......................................................................................... 11 Acknowledgments.......................................................................................... 12 References...................................................................................................... 13 Appendix: Summary of Water Quality Data from Primary Monitoring Stations ......................................................................................................... 15 ACE Basin ................................................................................................ 17 Santee Basin ............................................................................................. 18 Savannah Basin ......................................................................................... 20 Pee Dee Basin............................................................................................ 21 Zebra Mussels in South Carolina: The Potential Risk of Infestation Introduction: Non-native invasive species, such as zebra as a model for several states. Because three of mussels, cost the U.S. economy an estimated our largest rivers, the Broad, Catawba, Pee Dee, $137 billion annually in lost production and and several smaller rivers originate in North control costs (Pimentel et al., 2000). In the Carolina, we adopted their methodology for this absence of native predators and diseases, exotic assessment. Together, the North Carolina and organisms may develop very large populations South Carolina assessments provide a uniform that create severe ecological and economic zebra mussel risk assessment for three major problems. When such invasions occur in our river basins in the South Atlantic Slope Drainage. lakes and rivers they can disrupt whole aquatic Hopefully, this document will serve as a ecosystems and impair important municipal, valuable resource for public and private water industrial, agricultural, and recreational uses of use interests to plan for and prevent major our waterways. adverse impacts from zebra mussels when they The S.C. Department of Natural Resources finally arrive. (SCDNR) attempts to prevent and manage aquatic invasive species problems through its Aquatic Nuisance Species Program. Following Zebra Mussel Biology and Dispersal: the introduction of zebra mussels in the Great The zebra mussel, Dreissena polymorpha, is Lakes, the SCDNR and S.C. Sea Grant a freshwater bivalve mollusk (mussel) native to Consortium formed the Zebra Mussel Task Force the drainage basins of the Aral, Black and to help identify interested parties and to bring Caspian Seas in Eastern Europe and western focus to this issue. Composed of representatives Asia. They can reach lengths of up to two inches from the public and private sector, the task force but are usually about the size of a fingernail (10- has served as an effective communication and 20 mm). education network for those entities most at risk Adult zebra mussels have conspicuous dark of being impacted by zebra mussel infestations. parallel stripes across the shell, hence the The main objective of this study was to common name “zebra” mussel. While these determine the relative risk of zebra mussel zebra stripes are usually in regular striped infestations in public waters throughout the state. patterns, a variety of patterns can occur in local Although several excellent risk assessments have populations (Fig. 1). been conducted independently by electric and water utilities in South Carolina, these studies focused primarily on water bodies used by the utilities, which left large areas of the state unstudied. In addition, water quality criteria used to assess the potential for zebra mussel colonization were not consistent among all the studies, so the results were not directly comparable. A secondary objective was to develop a risk assessment that was not only useful to South Carolina but complimented existing assessments in the region. Fortunately, North Carolina conducted an excellent statewide zebra mussel assessment in 1997 that has served Figure 1. Variations in zebra mussel shell patterns. The Potential Risk of Infestation 1 Adult zebra mussels have conspicuous byssal were successfully introduced into North America threads extending from the lower portion of the in the 1980’s in Lake St. Clair in the Great Lakes shell, which are used to attach to hard, through ballast water discharge. Once submerged substrates (Fig. 2). The mussels often established, they spread rapidly throughout the attach to each other creating “barnacle-type” Great Lakes, Hudson River and upper colonies. Reproduction is sexual with females Mississippi River systems by 1991. Zebra producing up to one-half million eggs per year. mussels have exhibited strong genetic plasticity After fertilization, eggs hatch into veliger larvae, and have tolerated hostile environments beyond which disperse with other plankton in the water their traditional environmental ranges in their column. Veliger larvae change into postlarvae, native area. It was initially thought that water remain planktonic for a while, and then settle on temperatures in the southern United States would and attach to smooth, hard objects where they prohibit colonization in this area but by the mid develop into adults. Zebra mussels feed by 1990’s zebra mussel colonies were documented filtering plankton from the water. They are well as far south as Louisiana on the Mississippi known for their filtering efficiency and ability to River, as far west as Oklahoma on the Arkansas clarify water. River, and as far east as Knoxville on the Tennessee River (Fig. 3). Currently, they do not occur in the Atlantic slope drainages from Virginia south to Florida. Figure 2. Byssal threads used to anchor to substates. In South Carolina, adult zebra mussels may be confused with two other small bivalves, Corbicula (Asiatic clam) and Mytilopsis. Figure 3. Documented zebra mussel range in the United States as of November 2000. Corbicula can be distinguished