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



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

  • Assessment of the mussel fauna in the area impacted by dredging for the Green River Ferry, Mammoth Cave National Park.
  • Establish NEPs of two endangered mussel species in the lower French Broad River.
  • Life history of the Barrens heelsplitter (Lasmigona sp.).
  • Predicting the effects on endangered mussels from incremental decreases in minimum flows.
  • Reintroduction of mussels into the Little Tennessee River at the Calderwood Dam By-Pass.
  • Research directed at the recovery of endangered mussels.

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.