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Energy and Environment Directorate

Brett Pflugrath

Brett Pflugrath

Pacific Northwest National Laboratory
PO Box 999
Richland, WA 99352
(509) 375-6521


Brett Pflugrath joined the Ecology Group of PNNL’s Energy and Environment Directorate in 2007. In 2013, he left PNNL to conduct a PhD at the University of New South Wales in Sydney, Australia. After completing his PhD, Brett returned to the Ecology group in 2018 as a Post-Doctorate Research Associate. Brett is an international expert on downstream fish passage, having conducted research in Europe, Asia, Australia, and North America. He specializes in barotrauma, which occurs when fish are rapidly decompressed while passing downstream through hydro-turbines and weirs. Brett has also studied the effects of high fluid shear strain and collision on fish which may occur during downstream passage at hydraulic structures. One of the primary tools that Brett uses to conduct his research is the Sensor Fish, which was developed at PNNL. Additionally, Brett is experienced in the surgical implantation of acoustic and radio transmitters in fish and the installation/deployment of associated tracking equipment.

Research Interests

  • Downstream fish passage
  • Fish friendly turbine design and evaluation
  • Effects of rapid decompression on fish
  • Autonomous Sensor Fish
  • Bio-acoustics
  • Telemetry tracking animals

Education and Credentials

  • Ph.D., Environmental Engineering, University of New South Wales, Sydney, Australia, 2017
  • M.S., Environmental Science, Washington State University, Tri-Cities, 2011
  • B.S., Environmental Science, Northwest University, Kirkland, WA, 2007

Awards and Recognitions

  • 2016 – Best Student Oral Presentation, International Symposium on Ecohydraulics
  • 2015 – New South Wales DPI Fisheries John Holliday Student Conservation Award
  • 2014 – PNNL Energy and Environment Publication of the Year Award
  • 2013 – Sydney Engineering Excellence Awards Finalist Team Member

PNNL Publications


  • Pflugrath B.D., C.A. Boys, B. Cathers, and Z. Deng. 2019. "Over or under? Autonomous Sensor Fish reveals why overshot weirs may be safer than undershot weirs for fish passage." Ecological Engineering 132. PNNL-SA-138119. doi:10.1016/j.ecoleng.2019.03.010
  • Pflugrath B.D., R.A. Harnish, B.M. Rhode, B. Do Vale Beirao, K.M. Engbrecht, J.R. Stephenson, and A. Colotelo. 2019. "American Eel state of buoyancy and barotrauma susceptibility associated with hydroturbine passage." Knowledge and Management of Aquatic Ecosystems. PNNL-SA-138255. doi:10.1051/kmae/2019012


  • Boys C.A., W. Robinson, B. Miller, B.D. Pflugrath, L.J. Baumgartner, A. Navarro, and R.S. Brown, et al. 2016. "A piecewise regression approach for determining biologically relevant hydraulic thresholds for the protection of fish at river infrastructure." Journal of Fish Biology 88, no. 5:1677-1692. PNNL-SA-109599. doi:10.1111/jfb.12910


  • Brown R.S., A.H. Colotelo, B.D. Pflugrath, C.A. Boys, L.J. Baumgartner, Z. Deng, and L.G. Silva, et al. 2014. "Understanding barotrauma in fish passing hydro structures: a global strategy for sustainable development of water resources." Fisheries 39, no. 3:108-122. PNNL-SA-90945. doi:10.1080/03632415.2014.883570


  • Brown R.S., K.V. Cook, B.D. Pflugrath, L.L. Rozeboom, R.C. Johnson, J. McLellan, and T.J. Linley, et al. 2013. "Vulnerability of larval and juvenile white sturgeon to barotrauma: can they handle the pressure?." Conservation Physiology 1, no. 1:Article No. cot019. PNNL-SA-96109. doi:10.1093/conphys/cot019
  • Brown R.S., Z. Deng, K.V. Cook, B.D. Pflugrath, X. Li, T. Fu, and J.J. Martinez, et al. 2013. "A field evaluation of an external and neutrally buoyant acoustic transmitter for juvenile salmon: implications for estimating hydroturbine passage survival." PLoS One 8, no. 10:e77744. PNWD-SA-10136. doi:10.1371/journal.pone.0077744


  • Brown R.S., B.D. Pflugrath, A.H. Colotelo, C.J. Brauner, T.J. Carlson, Z. Deng, and A. Seaburg. 2012. "Pathways of Barotrauma in Juvenile Salmonids Exposed to Simulated Hydroturbine Passage: Boyle's Law vs. Henry's Law." Fisheries Research 121-122, no. 1:43-50. PNNL-SA-83903. doi:10.1016/j.fishres.2012.01.006
  • Brown R.S., B.D. Pflugrath, T.J. Carlson, and Z. Deng. 2012. "The Effect of an Externally Attached Neutrally Buoyant Transmitter on Mortal Injury during Simulated Hydroturbine Passage." Journal of Renewable and Sustainable Energy 4, no. 1:Article No. 013107. PNNL-SA-83175. doi:10.1063/1.3682062
  • Brown R.S., T.J. Carlson, A.J. Gingerich, J.R. Stephenson, B.D. Pflugrath, A.E. Welch, and M. Langeslay, et al. 2012. "Quantifying mortal injury of juvenile Chinook salmon exposed to simulated hydro-turbine passage." Transactions of the American Fisheries Society 141, no. 1:147-157. PNNL-SA-76832. doi:10.1080/00028487.2011.650274
  • Carlson T.J., R.S. Brown, J.R. Stephenson, B.D. Pflugrath, A.H. Colotelo, A.J. Gingerich, and P.L. Benjamin, et al. 2012. "The Influence of Tag Presence on the Mortality of Juvenile Chinook Salmon Exposed to Simulated Hydroturbine Passage: Implications for Survival Estimates and Management of Hydroelectric Facilities." North American Journal of Fisheries Management 32, no. 2:249-261. PNNL-SA-76806. doi:10.1080/02755947.2012.661384
  • Colotelo A.H., B.D. Pflugrath, R.S. Brown, C.J. Brauner, R.P. Mueller, T.J. Carlson, and Z. Deng, et al. 2012. "The effect of rapid and sustained decompression on barotrauma in juvenile brook lamprey and Pacific lamprey: implications for passage at hydroelectric facilities." Fisheries Research 129-130. PNNL-SA-85601. doi:10.1016/j.fishres.2012.06.001
  • Deng Z., J.J. Martinez, A.H. Colotelo, T.K. Abel, A.P. LeBarge, R.S. Brown, and B.D. Pflugrath, et al. 2012. "Development of External and Neutrally Buoyant Acoustic Transmitters for Juvenile Salmon Turbine Passage Evaluation." Fisheries Research 113, no. 1:94-105. PNNL-SA-79155. doi:10.1016/j.fishres.2011.08.018
  • Janak J.M., R.S. Brown, A.H. Colotelo, B.D. Pflugrath, J.R. Stephenson, Z. Deng, and T.J. Carlson, et al. 2012. "The Effects of Neutrally Buoyant, Externally Attached Transmitters on Swimming Performance and Predator Avoidance of Juvenile Chinook Salmon." Transactions of the American Fisheries Society 141, no. 5:1424-1432. PNNL-SA-82928. doi:10.1080/00028487.2012.688915
  • Pflugrath B.D., R.S. Brown, and T.J. Carlson. 2012. "Maximum Neutral Buoyancy Depth of Juvenile Chinook Salmon: Implications for Survival during Hydroturbine Passage." Transactions of the American Fisheries Society 141, no. 2:520-525. PNNL-SA-80256. doi:10.1080/00028487.2012.670187


  • Deng Z., R.S. Brown, T.J. Carlson, J.J. Martinez, A.H. Colotelo, B.D. Pflugrath, and T.K. Abel, et al. 2011. "Development of external and neutrally buoyant acoustic transmitters for turbine passage evaluation." In EPRI-DOE Conference on Environmentally-Enhanced Hydro Turbines, May 19-20, 2011, Washington DC, 155-164. Palo Alto, California:EPRI. PNNL-SA-79460. doi:10.2172/1057387


  • Stephenson J.R., A.J. Gingerich, R.S. Brown, B.D. Pflugrath, Z. Deng, T.J. Carlson, and M. Langeslay, et al. 2010. "Assessing barotrauma in neutrally and negatively bouyant juvenile salmonids exposed to simulated hydro-turbine passage using a mobile aquatic barotrauma laboratory." Fisheries Research 106, no. 3:271-278. PNNL-SA-72828. doi:10.1016/j.fishres.2010.08.006

Selected Publications


  • Boys CA, Pflugrath BD, Mueller M, Pander J, Deng ZD, Geist J. 2018. “Physical and hydraulic forces experienced by fish passing through three different low-head hydropower turbines.” Marine and Freshwater Research. doi:10.1071/MF18100
  • Pflugrath BD, Boys CA, Cathers B. 2018. “Predicting hydraulic structure-induced barotrauma in Australian fish species.” Marine and Freshwater Research. doi:10.1071/MF18137

Energy and Environment

Core Research Areas