Cooperative Fish and Wildlife Research Units Program: Vermont
Education, Research and Technical Assistance for Managing Our Natural Resources

Recently much of the popular science literature has focused on the concept of climate change. Thus far, there have been some very simple predictions on how climate change will affect temperature, especially in more northern latitudes. As ectotherms, fish are affected directly by any changes in temperature, which can range from altering foraging, reproduction, metabolism, migration timing, etc. In the Connecticut River, anadromous fish (e.g., Atlantic salmon (Salmo salar), American shad (Alosa sapidissima), sea lamprey (Petromyzon marinus)) are predicted to change migration patterns in relation to climate change. The life cycle complexity of migratory species introduces several unknowns regarding the transitions from freshwater to marine and back, and from tributary to mainstem in some species. The changing thermal regime will be accompanied by changes in discharge as a component of the altered water cycle. Predictions of changes in shorter-term weather patterns include more severe events; e.g., a tornado occurred in Vermont on May 9, 2009 and Hurricane Irene caused major damage in Vermont tributaries in August 2011. This backdrop provides an opportunity to expand on our previous modeling of Atlantic salmon migration in the Connecticut River. We explored how temperature, discharge, and the indirect effects of dams (by creating delays in migration) were related to survival of Atlantic salmon smolts. We worked in this area for several years using data from previous monitoring and research. The final phase of our efforts was to model juvenile American shad migration in response to changing environmental conditions.