Nathaniel (Than) Hitt, PhD
Dr. Nathaniel (Than) P. Hitt is a Research Fish Biologist at the USGS Eastern Ecological Science Center in Kearneysville, West Virginia
He holds a B.A. in Biology from the College of Wooster, an M.S. in Organismal Biology and Ecology from the University of Montana, and a Ph.D. in Fisheries and Wildlife Sciences from Virginia Tech. Dr. Hitt’s research investigates freshwater fish ecology from a landscape perspective, focusing on stream ecosystems in the Appalachian highlands. His research includes:
- Modeling fish habitat and population/community responses to environmental change
- Forecasting effects of climate change for fish habitat in headwater streams
- Effects of stream flow and temperature on fish population dynamics
- Optimizing conservation and restoration planning for native fishes
Professional Experience
2009-present: Research Fish Biologist, US Geological Survey, Eastern Ecological Science Center
2015-present: Adjunct Associate Professor, Department of Ecosystem Science and Management, Pennsylvania State University
2008-2009: Postdoctoral Researcher, US Geological Survey, Leetown Science Center
2007-2008: Postdoctoral Researcher, Virginia Tech, Department of Fisheries and Wildlife Sciences
2007-2008: Postdoctoral Researcher, Virginia Tech, Department of Fisheries and Wildlife Sciences
1999-2002: Graduate Research Assistant, University of Montana, Division of Biological Sciences
Education and Certifications
2007 PhD, Virginia Polytechnic Institute and State University, Blacksburg, VA, Department of Fisheries and Wildlife Sciences
2002 MS, University of Montana, Missoula, MT, Division of Biological Sciences, Organismal Biology and Ecology
1996 BA, The College of Wooster, Wooster, OH Biology, Honors
Science and Products
USGS Expands Studies of Brook Trout
The Past as a Prelude to the Future: Assessing Climate Effects on Native Trout in the U.S.
Bringing People, Data, and Models Together – Addressing Impacts of Climate Change on Stream Temperature
Video data for trout abundance estimation
Brook trout movement data related to cover and forage in an experimental stream system with associated water quality parameters
Seismic data for study of shallow mountain bedrock limits seepage-based headwater climate refugia, Shenandoah National Park, Virginia
Water and air temperature data from Shenandoah Valley streams, Virginia (2017)
Stream fish species abundance and associated physical habitat data in Catoctin Mountain Park (2015-2016)
Temperature data for study of shallow mountain bedrock limits seepage-based headwater climate refugia, Shenandoah National Park, Virginia
Air-water temperature data for the study of groundwater influence on stream thermal regimes in Shenandoah National Park, Virginia (ver. 2.0, May 3, 2018)
Heed the data gap: Guidelines for using incomplete datasets in annual stream temperature analyses
Modeling occupancy of rare stream fish species in the upper Cumberland and Kentucky River Basins
Comparison of underwater video with electrofishing and dive‐counts for stream fish abundance estimation
Paired air-water annual temperature patterns reveal hydrogeological controls on stream thermal regimes at watershed to continental scales
Spatial and temporal trends in Potomac River fish abundance linked to species traits
Distribution and status of trout and char in North America
Individual behaviour and resource use of thermally stressed brook trout Salvelinus fontinalis portend the conservation potential of thermal refugia
An integrated framework for ecological drought across riverscapes of North America
State-space analysis of power to detect regional brook trout population trends over time
Inferring watershed hydraulics and cold-water habitat persistence using multi-year air and stream temperature signals
Forecasting stream habitat and Brook Trout responses to climate change in Catoctin Mountain Park
Landform features and seasonal precipitation predict shallow groundwater influence on temperature in headwater streams
Non-USGS Publications**
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
Science and Products
- Science
Filter Total Items: 15
USGS Expands Studies of Brook Trout
The USGS has established an experimental stream lab in the Leetown Science Center.The Past as a Prelude to the Future: Assessing Climate Effects on Native Trout in the U.S.
Salmonids (a family of fish that includes salmon, trout, and char) are a keystone species for both aquatic and terrestrial ecosystems, and can be an early warning indicator of ecosystem health. Salmonids also have strong societal values and contribute enormously to regional economies and Native American cultures. Today, many native salmonid populations are small, highly fragmented, and isolated frBringing People, Data, and Models Together – Addressing Impacts of Climate Change on Stream Temperature
This study set out to answer the question: “What data and modeling frameworks are needed to provide scientists reliable, climate-informed, water temperature estimates for freshwater ecosystems that can assist watershed management decision making?” To accomplish this, the study gathered existing stream temperature data, identified data gaps, deployed stream temperature monitoring devices, and devel - Data
Filter Total Items: 19
Video data for trout abundance estimation
Rapid advances in video technology are enabling new strategies for species abundance estimation. Here we provide estimates of fish abundance derived from video data collected in a series of stream pools in Shenandoah National Park, Virginia (n=41). Two 360-degree cameras were simultaneously used at each pool site where 15-minutes of underwater footage was collected. Environmental data are providedBrook trout movement data related to cover and forage in an experimental stream system with associated water quality parameters
Brook trout is a species of conservation concern in the eastern US. In 2016, we evaluated brook trout movement patterns in response to food and cover treatments in an experimental stream system using RFID monitoring techniques at the USGS Leetown Science Center in Kearneysville, WV. Brook trout were tagged with 12mm HDX Passive Integrated Transponder (PIT) tags and monitored with Multi-Antenna HDXSeismic data for study of shallow mountain bedrock limits seepage-based headwater climate refugia, Shenandoah National Park, Virginia
A combination of long-term daily temperature records and depth to bedrock measurements were used to parametrize one-dimensional models of shallow aquifer vertical heat transport in Shenandoah National Park, VA, USA. Depth to bedrock can directly influence shallow aquifer flow and thermal sensitivity, but is typically ill-defined along the stream corridor in steep mountain catchments. We employed rWater and air temperature data from Shenandoah Valley streams, Virginia (2017)
This Data Release provides hourly records of air and water temperature within 5 watersheds (Beaver Creek, Dry River, Mossy Creek, Passage Creek & Spout Run) in the Shenandoah Valley, VA in the summer of 2017. Data loggers were deployed and retrieved by Trout Unlimited personnel and volunteers.Stream fish species abundance and associated physical habitat data in Catoctin Mountain Park (2015-2016)
This Data Release provides records of fish species abundance collected during summer 2015 using single pass backpack electrofishing within sections of Owens Creek, Big Hunting Creek, and Blue Blazes Creek (a tributary to Big Hunting Creek) in Maryland (USA). We also provide water and air temperature data collected during at 30 minute increments summers of 2015 and 2016. Stream physical habitat datTemperature data for study of shallow mountain bedrock limits seepage-based headwater climate refugia, Shenandoah National Park, Virginia
A combination of long-term daily temperature records and depth to bedrock measurements were used to parameterize one-dimensional models of shallow aquifer vertical heat transport in Shenandoah National Park, VA, USA. Spatially discontinuous roving water surface and bank temperatures surveys were performed with a handheld thermal infrared camera in September and December 2015 along the main channelAir-water temperature data for the study of groundwater influence on stream thermal regimes in Shenandoah National Park, Virginia (ver. 2.0, May 3, 2018)
USGS Leetown Science Center scientists collected hourly air and water temperature data at 79 site locations within nine watersheds in Shenandoah National Park, Virginia over four water years (2012-2015). Data were collected using HOBO Pro V2 thermographs (accuracy = 0.2 degrees Celsius, drift = less than 0.1 degrees Celsius per year per year). - Multimedia
- Publications
Filter Total Items: 45
Heed the data gap: Guidelines for using incomplete datasets in annual stream temperature analyses
Stream temperature data are useful for deciphering watershed processes important for aquatic ecosystems. Accurately extracting signal trends from stream temperature is essential for predicting responses of environmental and ecological indicators to change. Missing data periods are common for various reasons, and pose a challenge for scientists using temperature signal analysis to support stream reAuthorsZachary C. Johnson, Brittany G. Johnson, Martin A. Briggs, Craig D. Snyder, Nathaniel P. Hitt, Warren DevineModeling occupancy of rare stream fish species in the upper Cumberland and Kentucky River Basins
Biological conservation often requires an understanding of how environmental conditions affect species occurrence and detection probabilities. We used a hierarchical framework to evaluate these effects for several Appalachian stream fish species of conservation concern: Chrosomus cumberlandensis (BSD; blackside dace), Etheostoma sagitta (CAD; Cumberland arrow darter), and Etheostoma spilotum (KAD;AuthorsNathaniel P. Hitt, Karli M. Rogers, Karmann Kessler, Hannah E. MacmillanComparison of underwater video with electrofishing and dive‐counts for stream fish abundance estimation
Advances in video technology enable new strategies for stream fish research. We compared juvenile (age‐0) and adult (age 1+) Brook Trout Salvelinus fontinalis abundance estimates from underwater video with backpack electrofishing and dive‐count methods across a series of stream pools in Shenandoah National Park, Virginia (n = 41). Video methods estimated greater mean abundance of adult trout thanAuthorsNathaniel P. Hitt, Karli M Rogers, Craig D. Snyder, C. Andrew DolloffPaired air-water annual temperature patterns reveal hydrogeological controls on stream thermal regimes at watershed to continental scales
Despite decades of research into air and stream temperature dynamics, paired air-water annual temperature signals have been underutilized to characterize watershed processes. Annual stream temperature dynamics are useful in classifying fundamental thermal regimes and can enhance process-based interpretation of stream temperature controls, including deep and shallow groundwater discharge, when pairAuthorsZachary C. Johnson, Brittany G. Johnson, Martin A. Briggs, Warren Devine, Craig D. Snyder, Nathaniel P. Hitt, D. Hare, T. MinkovaSpatial and temporal trends in Potomac River fish abundance linked to species traits
Analysis of species abundance trends can inform an understanding of the underlying mechanisms. We evaluated spatial and temporal trends in fish species abundance in the non-tidal Potomac River (USA) from a dataset comprising 2841 seine-hauls with > 250,000 individual fish records across 10 sites and 43 years (1975-2017). The dataset contained 47 species from 7 taxonomic families, with species richAuthorsNathaniel P. Hitt, Karli Rogers, Zachary A. Kelly, Josh Henesy, John E. MullicanDistribution and status of trout and char in North America
No abstract available.AuthorsPhaedra Budy, Kevin B. Rogers, Yoichiro Kanno, Brooke E Penaluna, Nathaniel Hitt, Gary P. Thiede, Jason B. Dunham, Chad Mellison, William Somer, James DeRitoIndividual behaviour and resource use of thermally stressed brook trout Salvelinus fontinalis portend the conservation potential of thermal refugia
Individual aggression and thermal refuge use were monitored in brook trout Salvelinus fontinalis in a controlled laboratory to determine how fish size and personality influence time spent in forage and thermal habitat patches during periods of thermal stress. On average, larger and more exploratory fish initiated more aggressive interactions and across all fish there was decreased aggression at waAuthorsShannon L. White, B.C. Kline, Nathaniel Hitt, Tyler WagnerAn integrated framework for ecological drought across riverscapes of North America
Climate change is increasing the severity and extent of extreme droughts events, posing a critical threat to freshwater ecosystems, particularly with increasing human demands for diminishing water supplies. Despite the importance of drought as a significant driver of ecological and evolutionary dynamics, current understanding of drought consequences for freshwater biodiversity is very limited. WAuthorsRyan Kovach, Jason B. Dunham, Robert Al-Chokhachy, Craig Snyder, Erik A. Beever, Gregory T. Pederson, Abigail Lynch, Nathaniel P. Hitt, Christopher P. Konrad, Kristin Jaeger, Alan H. Rea, Adam J. Sepulveda, Patrick M. Lambert, Jason M. Stoker, J. Joseph Giersch, Clint C. MuhlfeldState-space analysis of power to detect regional brook trout population trends over time
Threats to aquatic biodiversity are expressed at broad spatial scales, but identifying regional trends in abundance is challenging owing to variable sampling designs, and temporal and spatial variation in abundance. We compiled a regional dataset of brook trout Salvelinus fontinalis counts across their southern range representing 326 sites from eight states between 1982-2014, and conducted a statiAuthorsKasey C. Pregler, R. Daniel Hanks, Evan S. Childress, Nathaniel P. Hitt, Daniel J. Hocking, Benjamin H. Letcher, Yoichiro KannoInferring watershed hydraulics and cold-water habitat persistence using multi-year air and stream temperature signals
Streams strongly influenced by groundwater discharge may serve as “climate refugia” for sensitive species in regions of increasingly marginal thermal conditions. The main goal of this study is to develop paired air and stream water annual temperature signal analysis techniques to elucidate the relative groundwater contribution to stream water and the effective groundwater flowpath depth. GroundwatAuthorsMartin A. Briggs, Zachary C. Johnson, Craig D. Snyder, Nathaniel P. Hitt, Barret L. Kurylyk, Laura K. Lautz, Dylan J. Irvine, Stephen T. Hurley, John W. LaneForecasting stream habitat and Brook Trout responses to climate change in Catoctin Mountain Park
Anticipating and mitigating the effects of climate change is a fundamental challenge for natural resource conservation. In this report, we respond to research needs identified by Catoctin Mountain Park (CATO) for native Brook Trout (Salvelinus fontinalis) conservation and management as part of the US Geological Survey (USGS) Natural Resources Preservation Program in FY15-16. We addressed three oveAuthorsNathaniel P. Hitt, Craig D. Snyder, Erin Snook, Zachary Johnson, Matthew MorganLandform features and seasonal precipitation predict shallow groundwater influence on temperature in headwater streams
Headwater stream responses to climate change will depend in part on groundwater‐surface water exchanges. We used linear modeling techniques to partition likely effects of shallow groundwater seepage and air temperature on stream temperatures for 79 sites in nine focal watersheds using hourly air and water temperature measurements collected during summer months from 2012 to 2015 in Shenandoah NatioAuthorsZachary C. Johnson, Craig D. Snyder, Nathaniel P. HittNon-USGS Publications**
Hitt, N.P. and M. Hendryx. 2010. Ecological integrity of streams linked to human cancer mortality rates. EcoHealth 7:91-104.Hitt, N.P. and P.L. Angermeier. 2008. River-stream connectivity affects fish bioassessment performance. Environmental Management 42:132-150.Hitt, N.P. and P.L. Angermeier. 2008. Evidence for fish dispersal from spatial analysis of stream network topology. Journal of the North American Benthological Society 27:304-320.Hitt, N.P. and B.R. Murphy. 2007. An inquiry-based case study for conservation biology. Journal of Virginia Science Education 2:43-50.Hitt, N.P. and P.L. Angermeier. 2006. Effects of adjacent streams on local fish assemblage structure in western Virginia: implications for biomonitoring. American Fisheries Society Symposium 48:75-86.Vignieri, S.N., E.M. Hallerman, B.J. Bergstrom, D.J. Hafner, A.P. Martin, P. Devers, P. Grobler and N.P. Hitt. 2006. Mistaken view of taxonomy undermines conservation of an evolutionarily distinct mouse: a response to Ramey et al. Journal of Animal Conservation 9:237-243.Allendorf, F.W., R. Leary, N.P. Hitt, K. Knudsen, M. Boyer and P. Spruell. 2005. Cutthroat trout hybridization and the U.S. Endangered Species Act: one species, two policies. Conservation Biology 19:1326-1328.Hitt, N.P. and C.A. Frissell. 2004. A case study of surrogate species in aquatic conservation planning. Aquatic Conservation: Marine and Freshwater Ecosystems 14:625-633.Allendorf, F.W., R. Leary, N.P. Hitt, K. Knudsen, L. Lundquist, and P. Spruell. 2004. Intercrosses and the U.S. Endangered Species Act: should hybridized populations be included as westslope cutthroat trout? Conservation Biology 18: 1203-1213.Hitt, N.P., C.A. Frissell, C.C. Muhlfeld and F.W. Allendorf. 2003. Spread of hybridization between native westslope cutthroat trout, Oncorhynchus clarki lewisi, and non-native rainbow trout, O. mykiss. Canadian Journal of Fisheries and Aquatic Sciences 60:1440-1451.Hitt, N.P. 2003. Immediate effects of wildfire on stream temperature. Journal of Freshwater Ecology 18:171-173.**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
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