Zebra Mussel Larvae Extremely Sensitive to Copper!
Ann Arbor, MI — Effective control of Zebra mussel larvae can be obtained well within 1 day of exposure to a copper-containing algaecide at concentrations much lower than allowable dosage for treatment of algal blooms. Adult mussels, however, cannot be controlled at the maximum dosage allowed by environmental regulations after 96 hours of exposure.
Several U.S. states are permitted to use copper-containing products such as Cutrine®-Ultra to control algal blooms in open waterways. So, when a new Zebra mussel infestation was discovered in an inland Minnesota lake and important recreational area in 2003, Minnesota became interested in looking into the effectiveness of using Cutrine®-Ultra to control mussel larvae as a short term control strategy for limiting the spread of the population.
"Researchers have discussed taking advantage of the sensitivity of mussel larvae for control measures in the past," says Alan Kennedy, a research biologist at the US Army Engineer Research and Development Center in Vicksburg, Mississippi. "Adults can be especially challenging to chemical control strategies since they may sense some chemicals in the water and close their shells for weeks. This limits their exposure."
The study findings were that an early life stage called the trochophore can be killed in the laboratory after just a few hours using copper exposures that were 50 times lower than the permitted dosage into water of 1 part per million. Killing adults with the algaecide was not possible after 24 hours exposure at almost 5 times the permitted dosage. Even after 96 hours of continuous exposure, it took almost 2 times the maximum allowable dosage of the algaecide to kill most of the adults. Control strategies that target more sensitive mussel larvae would require less chemical, which saves money and reduces unintended ecological impacts. Such a strategy would need to be coordinated with spawning events and repeated seasonally for several years (the approximate life expectancy of adult mussels) to achieve effective control of both population spread and recruitment.
Original Publication Information
Results of this study "Relative Sensitivity of Zebra Mussel (Dreissena polymorpha) Life-stages to Two Copper Sources," are reported by Alan J. Kennedy, Rod N. Millward, Jeffery A. Steevens, John W. Lynn and Karen D. Perry in the latest issue (Volume 32, No. 3, pp. 596-606) of the Journal of Great Lakes Research, published by the International Association for Great Lakes Research, 2006.
Contacts
For more information about the study, contact Alan Kennedy, US Army Engineer Research and Development Center, Environmental Laboratory, CEERD-EP-R, Vicksburg, MS 39180; Alan.J.Kennedy@erdc.usace.army.mil; (601) 634-3344.
For information about the Journal of Great Lakes Research, contact Marlene Evans, Editor, National Water Research Institute, 11 Innovation Boulevard, Saskatoon, SK, S7N 3H5, Canada; editor@iaglr.org; (608) 692-1076.
Links
Since 1967, IAGLR has served as the focal point for compiling and disseminating multidisciplinary knowledge on North America's Laurentian Great Lakes and other large lakes of the world and their watersheds. In part, IAGLR communicates this knowledge through publication of the Journal of Great Lakes Research, available to members in print and electronic form. A searchable archive of the journal is available online and includes the abstracts of articles from the journal's inception in 1975 through the most recent issue. In addition, complete articles are available to members who have signed up for an electronic subscription.