Nicholas Som, Ph.D.

Current Research Interests

  • Statistical methods for modeling habitat use
  • Statistical methods for modeling fish disease dynamics
  • Spatial sampling
  • Life-cycle dynamics modeling


B.S. Mathematics, 2000, Regis University
M.S. Statistics, 2002, Washington State University
Ph.D. Forest Science (Ecological Statistics), 2009, Oregon State University

Courses Taught

STAT 410/510 Modern Statistical Modeling


  • Robinson, H. E., Henderson, M. J., Perry, R. W., Goodman, D. H., & Som, N. A. 2022. From site to system: Approaches for producing system-wide estimates of fish habitat in large rivers. River Research and Applications, 38(1), 119– 130.
  •  Turecek, A., Payton, Q., Alexander, J. D., Goodman, G., Evans, A. F., Som, N. A. 2021. Reducing river flows to control a parasitic salmonid disease in the Klamath River: simulations question the efficacy of desiccation as a management tool. North American Journal of Fisheries Management 41: 1215-1224.
  •  Payton, Q. and Som, N.A. 2021. Evaluating alternative hierarchical modelling approaches for the estimation of salmonid smolt abundance. North American Journal of Fisheries Management 41: 1182-1193
  •  Lehman, B. M., et al. (including N.A. Som). 2020. Disease in Central Valley Salmon: Status and Lessons from Other Systems. San Francisco Estuary and Watershed Science 18(3). doi:
  •  Pearse, A. R., McGree, J. M., Som, N. A., Leigh, C., Maxwell, P., Ver Hoef, J. M., Peterson, E. E. 2020. SSNdesign – An R package for pseudo-Bayesian optimal and adaptive sampling designs on stream network. PLOS ONE 15(9): e0238422.
  •  Robinson, H. E., Alexander, J. D., Hallett, S. L., Som, N. A. 2020. Prevalence of infection in hatchery-origin Chinook Salmon correlates with abundance of Ceratonova shasta spores: implications for management and disease risk. North American Journal of Fisheries Management 40: 959-972. doi: 10.1002/nafm.10456.
  •  Rub, A. M. W., Som, N. A., Hederson, M. J., Sandford,B. P., Van Doornik, D. M., Teel, D. J., Tennis, M., Langness, O., van der Leeuw, B., Huff, D. D. 2019. Changes in adult Chinook salmon (Oncorhynchus tshawytscha) survial within the lower Columbia River amid increasing pinniped abundance. Canadian Journal of Fisheries and Aquatic Sciences 76:1862-1873. doi: 10.1139/cjfas-2018-0290.
  •  Goodman, D. G., Som, N. A., Hetrick, N. J. 2018. Increasing the availability and spatial variation of spawning habitats through ascending baseflows. River Research and Applications 34(7): 844-853. doi: 10.1002/rra.3302.
  •  Som, N. A., Perry, R. W., Jones, E. C., De Juilio, K., Petros, P. Pinnix, W. D., Rupert, D. L. 2018. N-mix for fish: estimating riverine salmonid habitat selection via N-mixture models. Canadian Journal of Fisheries and Aquatic Sciences 75(7): 1048-1058. doi: 10.1139/cjfas-20017-0027.
  •  Manhard, C. V., Som, N. A., Perry, R. W., Plumb, J. M. 2018. A laboratory-calibrated model of coho salmon growth with utility for ecological analyses. Canadian Journal of Fisheries and Aquatic Sciences 75(5): 682-690. doi: 10.1139/cjfas-2016-0506.
  •  Wright, K. A., Goodman, D. H., Som, N. A., Alvarez, J., Martin, A., Hardy, T. B. 2017. Improving hydrodynamic modelling: an analytical framework for assessment of two-dimensional hydrodynamic Models. River Research and Applications., 33: 170–181. doi: 10.1002/rra.3067.
  •  Alexander, J.D., Bartholomew, J.L., Wright, K.A., Som, N.A., Hetrick, N.J. 2016. Integrating models to predict distribution of the invertebrate host of myxosporean parasites. Freshwater Science 35(4): 1263-1275.
  •  Som, N.A., Goodman, D.H., Perry, R.W., Hardy, T.B. 2016. Habitat suitability criteria via parametric distributions: estimation, model selection and uncertainty. River Research and Applications. 32(5): 1128-1137. doi: 10.1002/rra.2900.
  •  Goodman, D.H., Reid, S.B., Som, N.A., Pytress, W.R. 2015. The punctuated seaward migration of Pacific Lamprey (Entosphenus tridentatus): environmental cues and implications for streamflow management. Canadian Journal of Fisheries and Aquatic Sciences., 72(12): 1817-1828. doi: 10.1139/cjfas-2015-0063.
  •  Som, N.A., Monestiez, P., Ver Hoef, J.M., Zimmerman, D.L., Peterson , E.E. 2014. Spatial sampling on streams: Principles for inference on aquatic networks. Environmetrics. 25(5): 306-323. doi: 10.1002/env.2284
  •  Goodman, G.H., Som, N.A., Alvarez, J., Martin, A. 2014. A mapping technique to evaluate age-0 salmon habitat response from restoration. Restoration Ecology. Early View Online. doi: 10.1111/rec.12148.
  •  Isaak, D. et al. (including N.A. Som). 2014. Applications of spatial statistical network models to stream data. Wiley Interdisciplinary Reviews: Water. 1(3): 277-294.
  •  Ray, A.R., Perry, R.W., Som, N.A., Bartholomew, J.L. 2014. Using cure models for analyzing the influence of pathogens on salmon survival. Transactions of the American Fisheries Society. 143(2): 387-398.
  •  Wenger, S.J., Som, N.A., Dauwalter, D.C., Isaak, D.J., Neville, H.M., Luce, C.H., Fausch, K.D., Dunham, J.B., Young, M.K., Reiman, B.E. 2013. Probabilistic accounting of uncertainty in forecasts of species distributions under climate change. Global Change Biology. 19(11): 3343-3354. doi: 10.1111/gcb.12294.
  •  Malakauskas, D.M., Willson, S.J., Wilzback, M.A., Som, N.A.. 2013. Flow variation and substrate type affect dislodgement of the freshwater polychaete, Manayunkia speciosa. Freshwater Science. 32(3): 862-873. doi: 10.1899/12-140.1.
  •  Peterson, E.E. et al. (including N.A. Som). 2013. Modelling dendritic ecological networks in space: an integrated network perspective. Ecology Letters. 16(5): 707-719. doi: 10.1111/ele.12084.
  •  Som, N.A., Zegre, N.P., Ganio, L.M., Skaugset, A.E. 2011. Corrected prediction intervals for change detection in paired watershed studies. Hydrological Sciences Journal. 57(1): 134-143.
  •  Zegre, N., Skaugest, A.E., Som, N.A., McDonnell, J.J., Ganio, L.M.. 2010. In Lieu of the paired catchment approach: Hydrologic model change detection at the catchment scale. Water Resources Research. 46. W11544, doi:10.1029/2009WR008601.
  •  Zegre, N.P., Som, N.A. Detecting the effects of forest harvesting on streamflow using hydrologic model change detection. Conference Proceedings of the 17th Central Hardwoods Forest Conference. April 5-7, 2010. Lexington, KY.
  •  Betts, M.G., Ganio, L.M., Huso, M.M.P., Som, N.A., Huettmann, F., Bowman, J.,Wintle, B.A. 2009. Comment on ‘‘Methods to account for spatial autocorrelation in the analysis of species distributional data: a review’’. Ecography. 32: 374-378.