Nathaniel Hitt, PhD
Biography
Dr. Nathaniel (Than) P. Hitt is a Research Fish Biologist at the U.S. Geological Survey’s (USGS) Leetown 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 communities population dynamics
Links to media coverage in The Washington Post, The Washington Post, McClatchy News, Herald-Mail, Discovery News, EarthSky.org, Shepherdstown Chronicle, and National Geographic News Watch
Link to Google Scholar profile
Link to Project eTrout: crowdsourcing trout ecology data with virtual reality. See a demo 360-video here.
Visit a webmap of future brook trout habitat in Catoctin Mountain Park, and see the underlying methods (2018).
Watch a National Park Service webinar "forecasting fish habitat responses to climate change: importance of groundwater-surface water interactions" (2018)
Visit a webmap of stream-groundwater modeling results in Shenandoah National Park (2017).
Read an article announcing the Presidential Early Career Award for Scientists and Engineers (2017).
Watch a timelapse video of stream flow in Catoctin Mountain Park over a year (2016).
Watch a video of brook trout feeding in the LSC Experimental Stream Laboratory.
Watch a video introducing the LSC Experimental Stream Laboratory.
Watch a presentation on the importance of stream network topology for brook trout recruitment in 2016.
Watch a presentation entitled "spatial structure of stream thermal sensitivity affects climate change forecasts for brook trout" given at James Madison University in 2013.
Hear a radio segment on my work investigating brook trout responses to climate change.
Download a final report to USFWS on Kentucky arrow darter and blackside dace relations to stream conductivity.
Download a pdf of slides presented to USFWS, OSM, and TDEC regarding conductivity thresholds for abundance of imperiled stream fishes (June 9, 2015).
Watch a video citing our research on American eel responses to dam removal.
New York Times quote of the day (June 21, 2015).
Publications
Budy, P., J. Dunham, N.P. Hitt, Y. Kanno, B. Penaluna, K.B. Rogers, and G. Thiede. In press. Distribution and status of trouts and chars in North America. Chapter 8 In: Diversity and Status of Trouts and Chars of the World. J. Kershner, J. Williams, B. Gresswell, and J. Lobon-Cervia, eds.
White, S.L., B.C. Kline, N.P. Hitt, and T. Wagner. 2019. Individual behaviour and resource use of thermally stressed brook trout Salvelinus fontinalis portend the conservation potential of thermal refugia. Journal of Fish Biology [Link]
Pregler, K.C., R.D. Hanks, E. Childress, N.P. Hitt, D.J. Hocking, B.H. Letcher, T. Wagner, and Y. Kanno. 2019. State-space analysis of power to detect regional brook trout population trends over time. Canadian Journal of Fisheries and Aquatic Sciences [Link]
Kovach, R., J. Dunham, R. Al-Chokhachy, C. Snyder, J. Young, A. Lynch, C. Konrad, K. Jaeger, N.P. Hitt, B. Letcher, A. Rea, A. Sepulveda, G. Pederson, P. Lambert, C. Torgersen, J. Stoker, and C. Muhlfeld. 2019. An integrated framework for ecological drought across riverscapes of North America. BioScience 69:418-431 [Link]
Briggs, M.A., Z.C. Johnson, C.D. Snyder, N.P. Hitt, B.L. Kurylyk, L. Lautz, D.J. Irvine, S.T. Hurley, and J.W. Lane. 2018. Inferring watershed hydraulics and cold-water habitat persistence using multi-year air and stream temperature signals. Science of the Total Environment 636:1117-1127. [Link]
Briggs, M.A., J.W. Lane, C.D. Snyder, E.A. White, Z.C. Johnson, D.L. Nelms, and N.P. Hitt. 2018. Shallow bedrock limits groundwater seepage-based headwater climate refugia. Limnologica 68:142-156. [Link]
Hitt, N.P., Snook, E.L., and D.L. Massie. 2017. Brook trout use of thermal refugia and foraging habitat influenced by brown trout. Canadian Journal of Fisheries and Aquatic Sciences 74:406-418. [Link]
Johnson, Z.C., C.D. Snyder, and N.P. Hitt. 2017. Landform features and seasonal precipitation predict shallow groundwater influence on temperature in headwater streams. Water Resources Research 53:5788-5812. [Link]
Blazer, V.S., N.P. Hitt, C.D. Snyder, and E. Snook. 2016. Dermocystidium sp. infection in Blue Ridge Sculpin Cottus caeruleomentum captured in Maryland, USA. Journal of Aquatic Animal Health 28:143-149. [Link]
Kanno, Y., Pregler, K.C., Hitt, N.P., Letcher, B.H., Hocking, D.J., and J.E.B. Wofford. 2016. Seasonal temperature and precipitation regulate brook trout young-of-the-year abundance and population dynamics. Freshwater Biology 61:88-99. [Link]
Hitt, N.P., Floyd, M., Compton, M. and K. McDonald. 2016. Threshold responses of Blackside Dace (Chrosomus cumberlandensis) and Kentucky Arrow Darter (Etheostoma spilotum) to stream conductivity.Southeastern Naturalist 15:41-60. [Link]
Shephard, B.B., Al-Chokhachy, R., Koel, T., Kulp, M.A., and N.P. Hitt. 2016. Likely responses of native and invasive salmonid fishes to climate change in the Rocky Mountains and Appalachian mountains. Chapter 12 In: Climate Change in Wildlands. Hansen, A.J., Monahan, W.B., Theobald, D.M., and S.T. Olliff, eds. Island Press. [Link]
Snyder, C.D., Hitt, N.P., and J.A. Young. 2015. Accounting for the influence of groundwater on the thermal sensitivity of headwater streams to climate change. Ecological Applications 25:1397-1419. [Link]
Kanno, Y., Letcher, B.H., Hitt, N.P., Boughton, D.A., Wofford, J.E.B., and E.F. Zipkin. 2015. Seasonal weather patterns drive population vital rates and persistence in a stream fish. Global Change Biology 21:1856-1870. [Link]
Hitt, N.P. , Bonneau, L.K., Jayachandran, K.V. and M.P. Marchetti. 2015. Freshwater ecosystems and biodiversity. Lessons in Conservation 5:5-16. [Link]
Hitt, N.P. and D.B. Chambers. 2014. Temporal changes in taxonomic and functional diversity of fish assemblages downstream from mountaintop mining. Freshwater Science 33:915-926. [Link]
Hitt, N.P. and D.R. Smith. 2014. Threshold-dependent sample sizes for selenium assessment with stream fish tissue. Integrated Environmental Assessment and Management 11:143-149. [Link]
Jastram, J.D., Snyder, C.D., Hitt, N.P., and K.C. Rice. 2013. Synthesis and interpretation of surface-water quality and aquatic biota data collected in Shenandoah National Park, Virginia, 1979-2009. US Geological Survey, Scientific Investigations Report 2013-5157. Reston, Virginia. 77 pg. [Link]
Hitt, N.P. and J.R Roberts. 2012. Hierarchical spatial structure of stream fish colonization and extinction. Oikos 121:127-137. [Link]
Iwanowicz., L.R., Blazer, V.S., Hitt, N.P., McCormick, S.D., DeVault, D., and C.A. Ottinger. 2012. Histologic, immunologic, and endrocrine biomarkers indicate contaminant effects in fishes of the Ashtabula River. Ecotoxicology 21:165-182. [Link]
Daily, J.P., Hitt, N.P., Smith, D.R., and C.D. Snyder. 2012. Experimental and environmental factors affect spurious detection of ecological thresholds. Ecology 93:17-23. [Link]
Hitt, N.P., Eyler, S., and J.E.B. Wofford. 2012. Dam removal increases American eel abundance in distant headwater streams. Transactions of the American Fisheries Society 141:1171-1179. [Link]
Smith, D.R., Snyder, C.D., Hitt, N.P., Young, J.A., and S.P. Faulkner. 2012. Shale gas development and brook trout: scaling best management practices to anticipate cumulative effects. Environmental Practice. 14:1-16. [Link]
Hitt, N.P. and P.L. Angermeier. 2011. Fish community and bioassessment responses to stream network position. Journal of the North American Benthological Society 30:296-309. [Link]
Brown, B. L., Swan, C.M., Auerbach, D., Campbell Grant, E., Hitt, N.P., Maloney, K.O., and C. Patrick. 2011. Metacommunity theory as a multi-species, multi-scale framework for studying the influence of river network structure on riverine communities and ecosystems. Journal of the North American Benthological Society 30:310-327. [Link]
Roberts, J.R. and N.P. Hitt. 2010. Longitudinal structure in stream fish communities: evaluating conceptual models with temporal data. American Fisheries Society Symposium 73: 281-299. [Link]
Betz, R., Hitt, N.P., Dymond, R., and C. D. Heatwole. 2010. A method for delineating stream network topology over large geographic extents. Journal of Spatial Hydrology 10:15-29. [Link]
Hodson, P., Reash, R., Canton, S.P., Campbell, P., Delos, C., Fairbrother, A., Hitt, N.P., Miller, L.L., and H.S. Ohlendorf. 2010. Selenium risk characterization. In: Ecological Assessment of Selenium in the Aquatic Environment. Chapman, P.M., et al., eds. Society for Ecotoxicology and Chemistry Press. [Link]
Hitt, N.P. and M. Hendryx. 2010. Ecological integrity of streams linked to human cancer mortality rates. EcoHealth 7:91-104. [Link]
Hitt, N.P. and P.L. Angermeier. 2008. River-stream connectivity affects fish bioassessment performance. Environmental Management 42:132-150. [Link]
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. [Link]
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.[Link]
Vignieri, S.N., Hallerman, E.M., Bergstrom, B.J., Hafner, D.J., Martin, A.P., Devers, P., Grobler, P. 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. [Link]
Allendorf, F.W., Leary, R., Hitt, N.P., Knudsen, Boyer, M., and P. Spruell. 2005. Cutthroat Trout Hybridization and the U.S. Endangered Species Act: One Species, Two Policies. Conservation Biology 19: 1326-1328. [Link]
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. [Link]
Allendorf, F.W., Leary, R., Hitt, N.P., Knudsen, K., Lundquist, L., 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. [Link]
Hitt, N.P., Frissell, C.A., Muhlfeld, C.C. 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. [Link]
Hitt, N.P. 2003. Immediate effects of wildfire on stream temperature. Journal of Freshwater Ecology 18(1): 171-173. [Link]
Science and Products
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 ...
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...
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. Over the past several years, many regions have experienced extreme droughts, fueled by prolonged periods of reduced precipitation and exceptionally warm temperatures...
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,...
Project eTrout
Welcome to Project eTrout [instructional video]!
Click here to begin.
Click here for a summary of results.
Virtual reality (VR)...
USGS Expands Studies of Brook Trout
The USGS has established an experimental stream lab in the Leetown Science Center.
Bringing 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...
An 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...
Kovach, Ryan; Dunham, Jason B.; Al-Chokhachy, Robert; Snyder, Craig; Beever, Erik A.; Pederson, Gregory T.; Lynch, Abigail; Hitt, Nathaniel P.; Konrad, Christopher P.; Jaeger, Kristin; Rea, Alan H.; Sepulveda, Adam J.; Lambert, Patrick M.; Stoker, Jason M.; Giersch, J. Joseph; Muhlfeld, Clint C. State-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...
Pregler, Kasey C.; Hanks, R. Daniel; Childress, Evan S.; Hitt, Nathaniel P.; Hocking, Daniel J.; Letcher, Benjamin H.; Kanno, Yoichiro Inferring 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...
Briggs, Martin A.; Johnson, Zachary C.; Snyder, Craig D.; Hitt, Nathaniel P.; Kurylyk, Barret L.; Lautz, Laura K.; Irvine, Dylan J.; Hurley, Stephen T.; Lane, Jr., John W. Shallow bedrock limits groundwater seepage-based headwater climate refugia
Groundwater/surface-water exchanges in streams are inexorably linked to adjacent aquifer dynamics. As surface-water temperatures continue to increase with climate warming, refugia created by groundwater connectivity is expected to enable cold water fish species to survive. The shallow alluvial aquifers that source groundwater seepage to headwater...
Briggs, Martin A.; Lane, John W.; Snyder, Craig D.; White, Eric A.; Johnson, Zachary; Nelms, David L.; Hitt, Nathaniel P. Forecasting 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...
Hitt, Nathaniel P.; Snyder, Craig D.; Snook, Erin; Johnson, Zachary; Morgan, Matthew Landform 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...
Johnson, Zachary C.; Snyder, Craig D.; Hitt, Nathaniel P. Brook trout use of thermal refugia and foraging habitat influenced by brown trout
The distribution of native brook trout (Salvelinus fontinalis) in eastern North America is often limited by temperature and introduced brown trout (Salmo trutta), the relative importance of which is poorly understood but critical for conservation and restoration planning. We evaluated effects of brown trout on brook trout behavior and habitat use...
Hitt, Nathaniel P.; Snook, Erin; Massie, Danielle L. Dermocystidium sp. infection in Blue Ridge Sculpin captured in Maryland
Raised pale cysts were observed on Blue Ridge Sculpin Cottus caeruleomentum during stream fish community surveys in Catoctin Mountain Park, Maryland. When examined histologically, preserved sculpin exhibited multiple cysts containing spherical endospores with a refractile central body characteristic of Dermocystidiumspp. Cysts were not observed on...
Blazer, Vicki S.; Hitt, Nathaniel P.; Snyder, Craig D.; Snook, Erin; Adams, Cynthia R. Threshold responses of Blackside Dace (Chrosomus cumberlandensis) and Kentucky Arrow Darter (Etheostoma spilotum) to stream conductivity
Chrosomus cumberlandensis (Blackside Dace [BSD]) and Etheostoma spilotum (Kentucky Arrow Darter [KAD]) are fish species of conservation concern due to their fragmented distributions, their low population sizes, and threats from anthropogenic stressors in the southeastern United States. We evaluated the relationship between fish...
Hitt, Nathaniel P.; Floyd, Michael; Compton, Michael; McDonald, Kenneth Seasonal temperature and precipitation regulate brook trout young-of-the-year abundance and population dynamics
Abundance of the young-of-the-year (YOY) fish can vary greatly among years and it may be driven by several key biological processes (i.e. adult spawning, egg survival and fry survival) that span several months. However, the relative influence of seasonal weather patterns on YOY abundance is poorly understood. We assessed the importance of...
Kanno, Yoichiro; Pregler, Kasey C.; Hitt, Nathaniel P.; Letcher, Benjamin H.; Hocking, Daniel; Wofford, John E.B. Accounting for groundwater in stream fish thermal habitat responses to climate change
Forecasting climate change effects on aquatic fauna and their habitat requires an understanding of how water temperature responds to changing air temperature (i.e., thermal sensitivity). Previous efforts to forecast climate effects on brook trout habitat have generally assumed uniform air-water temperature relationships over large areas that...
Snyder, Craig D.; Hitt, Nathaniel P.; Young, John A. Threshold-dependent sample sizes for selenium assessment with stream fish tissue
Natural resource managers are developing assessments of selenium (Se) contamination in freshwater ecosystems based on fish tissue concentrations. We evaluated the effects of sample size (i.e., number of fish per site) on the probability of correctly detecting mean whole-body Se values above a range of potential management thresholds. We modeled Se...
Hitt, Nathaniel P.; Smith, David R.
Fish Populations Down Due to Mountaintop Mining
Appalachian streams impacted by mountaintop mining have less than half as many fish species and about a third as many fish as non-impacted streams, according to U.S. Geological Survey research published this week in the journal Freshwater Science.