|Progress and Results
Mobile organisms including fish predators and anadromous fish may be affected by climate change through several mechanisms. These include increased water temperature and altered discharge patterns. Anthropogenic impacts, especially fragmentation by dams, can exacerbate these effects by preventing or delaying movements. In this project, we use an individual based model to understand the relationships among water temperature, discharge, dams, movement patterns, and fish survival. Although previously this research has focused on anadromous fish in large NE US rivers, the methods and insights have relevance to motile organisms in other systems where temperature and discharge are changing with climate, especially in river systems fragmented by dams. In previous work, we modeled survival of Atlantic salmon smolts in the Connecticut River using three pieces of data: 1) spring river temperature (March – May) as triggers for the initiation of migration from tributaries into the main stem, 2) spring river discharge (March- May) as the determinant of how fast salmon smolts move from the tributaries to the estuary, and 3) spring river temperatures (March-May) in the main stem as the ultimate determinate of whether smolts will survive outmigration (2 -20 oC fish survive, otherwise they die). For this we used real river temperatures and real discharge collected throughout the Connecticut River watershed for a 10 year period. We will continue to take a modeling approach using fish life history and existing temperature and discharge data sets. Results should be applicable to mobile fish in large and small Great Plains rivers.
Marschall, E. A., M. E. Mather, D. L. Parrish, G. W. Allison,. J. McMenemy. 2011. Migration delays caused by anthropogenic barriers: dams, temperature, and success of migrating salmon smolts. Ecological Applications, 21: 3014-3031.
Mather, M.E., E.A. Marschall, and D.L. Parrish. Predicting interactive effects of climate change and dams on success of downstream-migrating salmon. Fish and Climate Change, The Fisheries Society of the British Isles Annual Symposium, Belfast, UK.