Differential Impacts of Hurricane Irene on Fish Communities and Trout Populations in a Catskill Mountain River, New York, USA

The Upper Esopus Creek, in the eastern Catskill Mountains of New York, was subjected to extreme flooding from the remnants of Hurricane Irene on August 28, 2011. Discharge at several USGS stream-flow gages in the basin approached or surpassed levels corresponding to the one percent chance of occurrence (>100 year flood). Although comparable floods have been found to severely reduce species abundances and disrupt entire ecosystems, the actual impacts on resident biota in the Esopus were only speculative. Fishery population and community data from quantitative surveys done at 9 sites during 2012 and 2013 in the Upper Esopus Creek were compared with data from annual (2009-11) surveys done before Tropical Storm Irene to characterize the potential impacts and recovery in streams across the basin.  Preliminary analysis indicates that the floods did not have a strong adverse impact on overall fish communities, and density and biomass of the entire community actually increased at some locations following the flood.   The density of young-of-the-year brown trout peaked in the year following the flood (2012) while rainbow trout did not have a strong year-class in 2012 and population density declined throughout the 5-year study.