1. Department of Ecosystem Sciences and Management The Pennsylvania State University University Park Pennsylvania 16802 USA
2. Intercollege Graduate Ecology Program The Pennsylvania State University University Park Pennsylvania 16802 USA
3. USGS Patuxent Wildlife Research Center SO Conte Anadromous Fish Research Center Turners Falls Massachusetts 01376 USA
4. USGS Patuxent Wildlife Research Center Laurel Maryland 20708 USA