James B. Layzer

       Professor Emeritus Biology and retired Unit Leader
       U.S. Geological Survey  100 4296                                                                                                    

Mailing address:
P.O. Box 5114
Cookeville, TN 38505

Office: 205 Pennebaker Hall
E-mail: This e-mail address is being protected from spambots, you need JavaScript enabled to view it


B.S., Fishery Biology, University of Massachusetts (1971)
M.S., Fishery Biology, University of Massachusetts (1974)
Ph.D., Zoology, Oklahoma State University (1982)

Professional Experience

1995-Present: Professor and Leader, Tennessee Cooperative Fishery Research Unit

1985-1995: Associate Professor (1990-1995), Assistant Professor (1985-1990), and Assistant Unit Leader, Tennessee Cooperative Fishery Research Unit

1982-1985: Fishery Biologist (1982-1983), Ecologist (1983-1985), Federal Energy Regulatory Commission, Washington, D.C.

1978-1982: University Fellow, Oklahoma Cooperative Fishery Research Unit, Oklahoma State University

1973-1978: Project Leader, U.S. Fish and Wildlife Service, Amherst, Mass.

Research Interests

Effects of stream regulation on aquatic biota; ecology and conservation of freshwater mussels; restoring and maintaining aquatic biodiversity; ecology of stream fishes.

Courses Taught


Recent Publications

Davis, V.M. and J.B. Layzer.  2012.  Life history of the fluted kidney shell Ptychobranchus subtentum.  American Midland Naturalist 167:79-95.

Weber, A.S. and J.B. Layzer.  2011.  A comparison of turtle sampling methods in a small lake in Standing Stone State Park, Overton County, Tennessee.  Journal of the Tennessee Academy of Science 86:45-52.

Ashton, M.J. and J.B. Layzer.  2010.  Summer microhabitat use by adult and young-of-year snail darters (Percina tanasi) in two rivers.  Ecology of Freshwater Fisheries, doi:10.1111/j.1600-0633.2010.00442.x.

Ashton, M.J. and J.B. Layzer.  2008.  Distribution of the threatened Snail Darter (Percina tanasi) in the upper Tennessee River drainage.  Journal of the Tennessee Academy of Science 83:52-56.

Simmons, J.W., J.B. Layzer and D.D. Smith.  2008.  Age-class structure and variability of two populations of the Bluemask Darter Etheostoma (Doration) sp.  American Midland Naturalist 160:300-309.

Layzer, J.B. and E.M. Scott, Jr. 2006. Restoration and colonization of freshwater mussels and fish in a southeastern United States tailwater. River Research and Applications 22:475-491.

Layzer, J.B. and J.R. Khym. 2005. Fish hosts for glochidia of the pheasantshell, Actinonaias pectorosa. Walkerana 14(31):79-85.

Layzer, J. B. and J. R. Heinricher. 2004. Coded wire tag retention in ebonyshell mussels Fusconaia ebena. North American Journal of Fisheries Management 24(1):228-230.

Simmons, J.W. and J.B. Layzer. 2004. Spawning behavior and habitat of the endangered bluemask darter, Etheostoma (Doration) sp. Copeia 2004(2):412-417.

Strayer, D. L., J. A. Downing, W. R. Haag, T. L. King, J. B. Layzer, T. J. Newton, and S. J. Nichols. 2004. Changing perspectives on pearly mussels, North America’s most imperiled animals. BioScience 54(5): 429-439.

Layzer, J. B. and T. R. Brady. 2003. Summer microhabitat of the endangered bluemask darter Etheostoma (Doration) sp. Journal of the Tennessee Academy of Science 78(2):55-57.

Layzer, J.B., B. Adair, S. Saha, and L.M. Woods. 2003. Glochidial hosts and other aspects of the life history of the Cumberland pigtoe (Pleurobema gibberum). Southeastern Naturalist 2(1):73-84.

Eads, C.B. and J.B. Layzer. 2002. How to pick your mussels out of a crowd: using fluorescence to mark juvenile freshwater mussels. Journal of the North American Benthological Society 21(3):476-486.

Gore, J.A., J.B. Layzer, and J. Mead. 2001. Macroinvertebrate instream flow studies after 20 years; a role in stream management and restoration. Regulated Rivers: Research & Management 17:527-542.

Hardison, B.S. and J.B. Layzer. 2001. Relations between complex hydraulics and the localized distribution of mussels in three regulated rivers. Regulated Rivers: Research & Management 17:77-84.

Khym, J.R. and J.B. Layzer. 2000. Host fish suitability for glochidia of Ligumia recta. The American Midland Naturalist 143:178-184.

Current Research Projects


Current Students

Mieko Camp (PhD); Georgia College and State University; Identifying stream sections with suitable food resources for reestablishing endangered mussels.

Ryan Foley (MS); University of Minnesota; Population ecology of endangered and imperiled mussels in the Duck River, Tennessee.

Kendall Moles (PhD); Arkansas Tech University; Predicting the effects on endangered mussels from incremental decreases in minimum flow.