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 and community ecotoxicology 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
Education
- 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
Professional experience
- 2009-present: Research Fish Biologist, US Geological Survey, Eastern Ecological Science Center
- 2018-present: Adjunct Associate Professor, Natural Resource Ecology & Management, Oklahoma State University
- 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
- 2002-2007: Graduate Research Assistant, Virginia Tech, Department of Fisheries and Wildlife Sciences
- 1999-2002: Graduate Research Assistant, University of Montana, Division of Biological Sciences
Science and Products
Study of stream fishes provides new framework to monitor climate change in the Chesapeake Bay headwaters
Enabling AI for citizen science in fish biology
Effects of introduced species on native brook trout: a guide to the scientific literature
Enabling AI for citizen science in fish ecology
Changing Freshwater Flows Affect Fish Populations in the Potomac River
Brook Trout Population Responses to Climate Variation Across the Southeast USA
Assessing native fish restoration potential in Catoctin Mountain Park
Project eTrout—Linking Research and Education with Virtual Reality
Brook trout vulnerability to drought: eastern component of USGS national integrated ecohydrological research and monitoring plans
A hydrological framework to improve precision of Vital Signs metrics in the Appalachian highlands
Project eTrout
USGS Expands Studies of Brook Trout
Fish species abundance data for selected streams of the Potomac River basin
Stream temperature observations during summer 2021 for sites in the Antietam Creek watershed, Maryland
Brook trout imagery data for individual recognition with deep learning
USGS EcoDrought Stream Discharge, Gage Height, and Water Temperature in Shenandoah National Park, Virginia
USGS EcoDrought Stream Discharge, Gage Height, and Water Temperature Data in Massachusetts
Stream temperature observations during summer 2021 for sites in the Sleepy Creek watershed, West Virginia
Annotated fish imagery data for individual and species recognition with deep learning
Spatial patterns of dewatering within watersheds of Shenandoah National Park, Virginia 2016 - 2021 (ver. 2.0, December 2021)
Stream temperature and sculpin growth data collected from Catoctin Mountain Park in 2019
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
Water and air temperature data from Shenandoah Valley streams, Virginia (2017)
Bedrock depth influences spatial patterns of summer baseflow, temperature and flow disconnection for mountainous headwater streams
Spout Run temperature study revisited- Part II: New insights for trout habitat from TU & USGS collaboration 2022
Stream size, temperature, and density explain body sizes of freshwater salmonids across a range of climate conditions
Life history strategies of stream fishes linked to predictors of hydrologic stability
Comparative morphology of freshwater sculpin inhabiting different environmental conditions in the Chesapeake Bay headwaters
Response of aquatic life to coal mining in Appalachia
Assessing native fish restoration potential in Catoctin Mountain Park
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
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: 14
Study of stream fishes provides new framework to monitor climate change in the Chesapeake Bay headwaters
Issue: The Chesapeake Bay Program (CBP) have identified four goals for actions toward change climate: • address the threats of climate change in all aspects of the partnership’s work; • prioritize communities, working lands, and most vulnerable habitats; • apply the best scientific, modeling, monitoring and planning capabilities; and • connect restoration outcomes with emerging opportunities. A...Enabling AI for citizen science in fish biology
Artificial Intelligence (AI) is revolutionizing ecology and conservation by enabling species recognition from photos and videos. Our project evaluates the capacity to expand AI for individual fish recognition for population assessment. The success of this effort would facilitate fisheries analysis at an unprecedented scale by engaging anglers and citizen scientists in imagery collection. This...Effects of introduced species on native brook trout: a guide to the scientific literature
Issue: Native brook trout (Salvelinus fontinalis) are of great ecological, cultural, and economic importance in eastern North America, and their restoration is a focus of the Chesapeake Bay Program. Introduced, non-native species can jeopardize native brook trout, and more information on these effects are needed.Enabling AI for citizen science in fish ecology
Artificial Intelligence (AI) is revolutionizing ecology and conservation by enabling species recognition from photos and videos. Our project evaluates the capacity to expand AI for individual fish recognition for population assessment. The success of this effort would facilitate fisheries analysis at an unprecedented scale by engaging anglers and citizen scientists in imagery collection.This projeChanging Freshwater Flows Affect Fish Populations in the Potomac River
Issue: Millions of people rely on the Potomac River for drinking water and recreational opportunities. The Potomac is Maryland’s most popular freshwater fishing destination, and the second largest river that enters the Chesapeake Bay. Restoring fisheries is also an important goal for the Chesapeake Bay Partnership restoration efforts.Brook Trout Population Responses to Climate Variation Across the Southeast USA
Brook trout are the only native fish from the salmon family in the southeastern United States. Despite their recreational and cultural significance, human activities, such as habitat degradation and introduction of non-native species, have led to serious declines of brook trout populations in the region. Stream temperature and flow alterations from climate change are projected to impact this cold-Assessing native fish restoration potential in Catoctin Mountain Park
Native species conservation is a fundamental purpose of National Parks. Catoctin Mountain Park (CATO) in Maryland supports a prized trout fishery and a healthy community of native fishes, with one exception: native Blue Ridge Sculpin (Cottus caeruleomentum) appear to have been extirpated from Big Hunting Creek above Cunningham Falls. Infection by a fungal-like protist Dermocystidium is...Project eTrout—Linking Research and Education with Virtual Reality
In the Chesapeake Bay headwaters, native brook trout are economically and culturally important and require high-quality, cold-water habitats. Project eTrout, led by the U.S. Geological Survey (USGS), explores the use of crowdsourcing and virtual reality (VR) to estimate the abundance of brook trout in headwater streams of the Chesapeake Bay watershed. Project eTrout engages students, anglers, and...Brook trout vulnerability to drought: eastern component of USGS national integrated ecohydrological research and monitoring plans
There is a growing and urgent need to develop and implement innovative strategies to research, monitor, and manage freshwater resources as societal demands escalate simultaneously with climate-driven changes in water availability.A hydrological framework to improve precision of Vital Signs metrics in the Appalachian highlands
Stream flow is a fundamental driver of ecological structure and function, but its influence on bioassessment measures is poorly understood. Although extreme flow conditions (e.g., floods and droughts) have long been known to play a central role in structuring stream communities, a mechanistic understanding of the linkages between flow variables, landscape and local physical characteristics, and...Project eTrout
Welcome to Project eTrout [instructional video]! Click here to begin. Click here for a summary of results. Virtual reality (VR) provides exciting opportunities for environmental education and research. We invite your participation in a new program to engage students, anglers, and citizen scientists in fish ecology and climate change research using new VR methods. Participants will learn about fish...USGS Expands Studies of Brook Trout
The USGS has established an experimental stream lab in the Leetown Science Center. - Data
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Fish species abundance data for selected streams of the Potomac River basin
This Data Release contains data on fish species abundance for selected streams of the Potomac River basin in eastern North America. This dataset supports analysis of karst streams in the Chesapeake Bay headwaters region and was funded by USGS Chesapeake Bay studies.Stream temperature observations during summer 2021 for sites in the Antietam Creek watershed, Maryland
This Data Release contains stream temperature observations for 28 sites in the Antietam Creek Watershed (Maryland) during summer 2021. Data were collected using Onset ProV2 temperature gages within perforated PVC cases attached to stream substrates with rebar. Temperature gages were deployed and retrieved by volunteers with the Antietam-Conococheague Watershed Alliance. Temperature records are proBrook trout imagery data for individual recognition with deep learning
This Data Release provides imagery data for the development of deep-learning models to recognize individual brook trout (n=435). Images were collected at the Paint Bank State Fish Hatchery (Paint Bank, VA) on August 9, 2021 using a GoPro Hero 9 camera mounted approximately 50 cm above a fish board. The Paint Bank State Fish Hatchery is operated by the Virginia Department of Wildlife Resources.USGS EcoDrought Stream Discharge, Gage Height, and Water Temperature in Shenandoah National Park, Virginia
The U.S. Geological Survey (USGS) Water Mission Area (WMA) - Ecosystems Mission Area (EMA) EcoDrought project is comprised of interdisciplinary teams in five pilot regions across the country. The over-arching project goal is to measure streamflow in headwater streams and to relate flow variation to stream fish population dynamics. For the catchments located in Shenandoah National Park, Virginia,USGS EcoDrought Stream Discharge, Gage Height, and Water Temperature Data in Massachusetts
The USGS Water Mission Area (WMA) - Ecosystems Mission Area (EMA) EcoDrought project is comprised of interdisciplinary teams in five pilot regions across the country. The over-arching project goal is to measure streamflow in headwater streams and to relate flow variation to stream fish population dynamics. In the northeast, the New England Water Science Center (NewEngWSC) partnered with the fishStream temperature observations during summer 2021 for sites in the Sleepy Creek watershed, West Virginia
This Data Release contains stream temperature observations for 10 sites in the Sleepy Creek Watershed (West Virginia) during summer 2021. Data were collected using Onset ProV2 temperature gages within perforated PVC cases attached to stream substrates with rebar. Temperature gages were deployed and retrieved by volunteers with the Sleepy Creek Watershed Association. Temperature records are provideAnnotated fish imagery data for individual and species recognition with deep learning
We provide annotated fish imagery data for use in deep learning models (e.g., convolutional neural networks) for individual and species recognition. For individual recognition models, the dataset consists of annotated .json files of individual brook trout imagery collected at the Eastern Ecological Science Center's Experimental Stream Laboratory. For species recognition models, the dataset consistSpatial patterns of dewatering within watersheds of Shenandoah National Park, Virginia 2016 - 2021 (ver. 2.0, December 2021)
These data describe longitudinal (upstream to downstream) patterns of dewatering during summer baseflow (July-September) conditions in nine watersheds in Shenandoah National park. In July-August of 2016 all nine watersheds (Jeremy's Run, Hazel River, Piney River, Hughes River, Staunton River, Whiteoak Canyon Run, Paine Run, Meadow Run, and Big Run) were evaluated for dewatering. In September of 20Stream temperature and sculpin growth data collected from Catoctin Mountain Park in 2019
This Data Release includes records of stream temperature during summer months of 2019 (10 sites) and records of Blue Ridge sculpin (Cottus caeruleomentum) weight for fish held in experimental enclosures for 45 days during the temperature sampling period (5 sites).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 HDXWater 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. - Multimedia
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Bedrock depth influences spatial patterns of summer baseflow, temperature and flow disconnection for mountainous headwater streams
In mountain headwater streams, the quality and resilience of summer cold-water habitat is generally regulated by stream discharge, longitudinal stream channel connectivity and groundwater exchange. These critical hydrologic processes are thought to be influenced by the stream corridor bedrock contact depth (sediment thickness), a parameter often inferred from sparse hillslope borehole information,Spout Run temperature study revisited- Part II: New insights for trout habitat from TU & USGS collaboration 2022
The Winchester TU Chapter partnered with US Geological Survey scientists to forecast habitat conditions for brook trout in Virginia. The results can be viewed here: https://chesapeake.usgs.gov/fishforecast/ TU members deployed stream temperature gages within several streams across the region: Dry River, Passage Creek, Spout Run, Beaver Creek, Mossy Creek. The USGS then used the temperature data toStream size, temperature, and density explain body sizes of freshwater salmonids across a range of climate conditions
Climate change and anthropogenic activities are altering the body sizes of fishes, yet our understanding of factors influencing body size for many taxa remains incomplete. We evaluated the relationships between climate, environmental, and landscape attributes and the body size of different taxa of freshwater trout (Salmonidae) in the USA. Hierarchical spatial modeling across a gradient of habitatsLife history strategies of stream fishes linked to predictors of hydrologic stability
Life history theory provides a framework to understand environmental change based on species strategies for survival and reproduction under stable, cyclical, or stochastic environmental conditions. We evaluated environmental predictors of fish life history strategies in 20 streams intersecting a national park within the Potomac River basin in eastern North America. We sampled stream sites during 2Comparative morphology of freshwater sculpin inhabiting different environmental conditions in the Chesapeake Bay headwaters
We compared body morphology of two freshwater sculpin taxa that inhabit distinct environmental conditions in the Chesapeake Bay watershed of eastern North America: Potomac sculpin (C. girardi, Robins; PS) and checkered sculpin (C. sp. cf. girardi; CS). Both taxa are endemic to the study area, but PS are more broadly distributed than CS which are limited to karst groundwater-dominated streams in thResponse of aquatic life to coal mining in Appalachia
No abstract available.Assessing native fish restoration potential in Catoctin Mountain Park
Biological conservation is a fundamental purpose of the National Park system, and Catoctin Mountain Park (CATO) supports high-quality habitat for native fishes in the headwaters of the Chesapeake Bay watershed in eastern North America. However, native Blue Ridge sculpin (Cottus caeruleomentum) have been extirpated in Big Hunting Creek above Cunningham Falls in CATO. Prior research indicates that iHeed 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 reModeling 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;Comparison 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 thanPaired 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 pairSpatial 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 richNon-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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