Ecology and management of the zebra mussel and other introduced aquatic nuisance species : a report based on presentations and discussions at the EPA Workshop on Zebra Mussels and Other Introduced Aquatic Nuisance Species, Saginaw Valley State University, Saginaw, Michigan, USA, September 26-28, 1990 / edited by J. David Yount ; prepared with the assistance of ESSA Environmental and Social Systems Analysts Ltd. and AScI Corporation