Use of telemetry to assess potential effects of Schoharie Reservoir waters on trout populations in the Upper Esopus Creek Active

Background - Turbid waters originating in the Schoharie Reservoir allegedly impair habitat and resident trout populations in Upper Esopus Creek; however, to date no scientific studies have documented adverse affects of altered thermal, suspended sediment (turbidity), and flow regimes on survival, growth, or behavior of trout or the health of their populations. The 424 mi2 Esopus Creek watershed is a tributary to the Hudson River in the south-central Catskill Mountains of New York State and is often considered to be two systems separated by the Ashokan Reservoir. The Upper Esopus Creek is considered the reach between its source, Winisook Lake, and the reservoir. Flows in the Upper Esopus Creek are supplemented by inputs from Schoharie Reservoir via an aqueduct connecting the reservoir (in the Mohawk River drainage) to Esopus Creek at the portal near Shandakan, NY. When warm and (or) turbid, those discharges purportedly cause adverse effects on fish and invertebrate assemblages at sites downstream of the portal. However, the releases are sometimes cooler than the Esopus and may sometimes provide thermal-refuge habitat (and benefits) for resident species. Because any impacts that the releases have on aquatic species or ecosystems in the basin are speculative, stakeholders (who disagree on the management of local resources) remain poorly informed about real problems and viable solutions in the basin. More information on survival, growth, and behavior of individual trout and on the health of local fish populations is needed to help make management decisions concerning portal releases, drinking water supplies, and fish resources in the watershed more ecologically sound.

Objectives - Primary objectives of the study are to assess potential beneficial and (or) adverse effects of releases from the Shandaken Portal on,

• behavior, survival, and growth of individual brown or rainbow trout (wild or hatchery),
• health of individual trout and their local populations, and
• availability and use of thermal refuges downstream of the portal.

Approach - The US Geological Survey (USGS), New York State Department of Environmental Conservation (DEC), New York City Department of Environmental Protection (DEP), Trout Unlimited, Cornell Cooperative Extension, and Cornell University began a multi-year study in 2009 using hatchery and wild brown trout to document differences in their rates of movement, use of thermal refuges, apparent survival, condition (health), and growth at two reaches in the Upper Esopus Creek (an upstream control reach and an impacted reach downstream of the portal). Differences in trout metrics will be compared to water chemistry, flow, turbidity, suspended sediments, and temperature data (generated via a companion study, Quantitative assessment of water quality in the upper Esopus Creek: fish, macroinvertebrates, periphyton, turbidity, and nutrients) to evaluate the potential beneficial and (or) adverse effects of releases from the portal on the (a) health of individual trout, (b) naturalized trout populations, (c) availability thermal refuges, and (d) use of thermal refuges downstream of the portal. Results from the study will be summarized in a master’s thesis and in one or more reports or refereed journal articles. All will be available, or linked to the web site, http://ny.usgs.gov.

Project
Location by County

Greene County, NY, Ulster County, NY