Are Low-head Dams Bad News for Darters?
Ann Arbor, MI — When the Munroe Falls low-head dam was built on the Cuyahoga River in 1817, people didn't know its effects on resident fish populations.
Darters are some of the most common and colorful fishes in Great Lakes tributaries, and are used by the EPA as water and habitat quality indicators. Before such lowhead dams were built, darter movements in tributaries were limited only by natural barriers, such as waterfalls, and by their own life history tendencies for migration. In 2005, the Ohio Environmental Protection Agency recommended that the Munroe Falls dam be removed due to low oxygen levels and some heavy metal contamination in the dam pool.
The present study by a graduate student (Amanda Haponski), a high school teacher (Thomas Marth), and professor (Carol Stepien) of Great Lakes Genetics Laboratory at the University of Toledo's Lake Erie Center examined possible genetic differences above and below the dam in greenside and logperch darters.
"We found evidence that the Munroe Falls dam had reduced gene flow in the logperch darter, but had no apparent effect on the greenside darter," says Amanda Haponski. "This could be the result of the logperch being naturally more migratory than the sedentary greenside darter."
The Munroe Falls dam was removed in November 2005, making this a potentially valuable baseline study. Follow-up data should be collected on genetic variation of darters throughout the Cuyahoga River, evaluating further potential barriers to gene flow.
Original Publication Information
Results of this study "Genetic Divergence across a Low-head Dam: A Preliminary Analysis using Logperch and Greenside Darters," are reported by Amanda E. Haponski, Thomas A. Marth and Carol A. Stepien in the latest issue (Volume 33, SI2, pp. 117-126) of the Journal of Great Lakes Research, published by the International Association for Great Lakes Research, 2007.
Contacts
For more information about the study, contact Carol A. Stepien, Lake Erie Center and Department of Environmental Sciences, University of Toledo, Toledo, OH 43606; carol.stepien@utoledo.edu, (419) 530-8360.
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.
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