1. Program In Organismic and Evolutionary Biology, University of Massachusetts, Amherst, MA 01003, USA
2. S.O. Conte Anadromous Fish Research Center, US Geological Survey/Leetown Science Center, One Migratory Way, Turners Falls, MA 01376, USA
3. Northern Research Station, US Forest Service, University of Massachusetts, Amherst, MA 01003, USA