Dr. Clay L Pierce

Assistant Unit Leader (Fisheries)
Collaborating NREM Faculty Member
Photograph of Clay Pierce

Clay Pierce is the Assistant Leader for Fisheries of the Iowa Cooperative Fish and Wildlife Research Unit at Iowa State University.  He supervises graduate students and does aquatic ecology and fisheries research in the lakes, rivers, and streams of Iowa.  He teaches courses in Stream Ecology and Fisheries Science.  Clay is a native of Minnesota, and received his Bachelors degree at Mankato State University, his Masters degree at the University of Kentucky, and his Ph.D. at the University of Maryland.  He was a postdoctoral researcher at McGill University and an assistant professor at Eastern Illinois University before assuming his present position in 1993.


Dr. Pierce’s research interests encompass aquatic ecology, fisheries science and fisheries management. Most of his research is applied and addresses information needs of state and federal natural resource agencies. Dr. Pierce collaborates with graduate students, university staff, and agency biologists.


A ECL 418/518
Stream Ecology. This dual-listed course explores the biological, chemical, physical, and geological processes shaping the structure and function of flowing water ecosystems. Topics from basic principles to synthetic theories of stream ecosystems are covered, as well as applications for management of water quality, biological integrity, and fisheries in streams. Laboratory sessions and field trips provide hands-on experiences. Students work on term projects in small groups. Graduate students enrolling in A Ecl 518 participate in bi-weekly discussions of primary literature. Team-taught with Dr. Thomas Isenhart.

A ECL 520
Fisheries Science. This graduate-level course explores concepts, approaches and techniques for assessment of recreational and commercial fisheries. Topics range from basic principles to applications and from individual fish to entire ecosystems. Computer simulation modeling, group projects, and discussion of primary literature are emphasized.


Swanson, J. E., C. L. Pierce, S. J. Dinsmore, K. L. Smalling, T. W. Stewart, M. W. Vandever, and E. Muths. 2019. Factors influencing anuran wetland occupancy in an agricultural landscape. Herpetologica 75(1):47-56. 

Mills, N., M. J. Weber, C. L. Pierce, and D. Cashatt. 2019. Factors influencing fish mercury concentrations in Iowa rivers. Ecotoxicology 28(2):229-241.

Katzenmeyer, E. D., C. L. Pierce, M. E. Colvin, T. W. Stewart, and S. E. Grummer. 2019. Fish growth changes over time in a Midwestern U.S. lake. Transactions of the American Fisheries Society 148:493-506.

Sullivan, C. J.,  M. J. Weber, C. L. Pierce, and C. A. Camacho. 2018. Influence of river discharge on grass carp occupancy dynamics in southeastern Iowa rivers. River Research and Applications 2018:1-8. DOI: 10.1002/rra.3385.

Swanson, J. E., C. L. Pierce, S. J. Dinsmore, K. L. Smalling, T. W. Stewart, M. W. Vandever, and E. Muths. In Press. Factors influencing anuran wetland occupancy in an agricultural landscape. Herpetologica.

Swanson, J. E., E. Muths, C. L. Pierce, S. J. Dinsmore, M. W. Vandever, M. L. Hladik, amd K. L. Smalling. 2018. Exploring the amphibian exposome in an agricultural landscape using telemetry and passive sampling. Scientific Reports 8:10045.

Sullivan, C. J., M. J. Weber, C. L. Pierce, D. H. Wahl, Q. E. Phelps, C. A. Camacho, and R. E. Colombo. 2018. Factors regulating year-class strength of silver carp throughout the Mississippi River Basin. Transactions of the American Fisheries Society 147:541-533.

Mills, N., D. Cashatt, M. J. Weber, and C. L. Pierce. 2018. A case study and a meta-analysis of seasonal variation in fish mercury concentrations. Ecotoxicology (2018). https://rdcu.be/NZ2c.

Fischer, J. R., B. D. Bakevich, C. P. Shea, C. L. Pierce, and M. D. Quist. 2018. Floods, drying, habitat connectivity, and fish occupancy dynamics in restored and unrestored oxbows of west-central Iowa. Aquatic Conservation: Marine and Freshwater Ecosystems. 2018:1-11.

Yaw, T. J., J. E. Swanson, C. L. Pierce, E. Muths, K. L. Smalling, M. W. Vandever, and B. A. Zaffarano. 2017. Placement of intracoelomic radiotransmitters and silicone passive sampling devices in northern leopard frogs (Lithobates pipiens). Journal of Herpetological Medicine and Surgery 27:111-115.

Sullivan, C. J., C. A. Camacho, M. J. Weber, and C. L. Pierce. 2017. Intra-annual variability of Silver Carp populations in the Des Moines River, USA. North American Journal of Fisheries Management 37:836-849. 

Reeves, R. A., C. L. Pierce, M. W. Vandever, E. Muths, and K. L. Smalling. 2017. Amphibians, pesticides, and the amphibian chytrid fungus in restored wetlands in agricultural landscapes. Herpetological Conservation and Biology 12:68-77. 

Reeves, R. A., C. L. Pierce, E. Muths., K. L. Smalling, R. W. Klaver, M. W. Vandever and W. A. Battaglin. 2016. Restored agricultural wetlands in central Iowa: habitat quality and amphibian response. Wetlands 36(1):101-110.

Colvin, M. E., C. L. Pierce, and T. W. Stewart. 2015. A food web modeling analysis of a Midwestern, USA eutrophic lake dominated by non-native Common Carp and Zebra Mussels. Ecological Modeling 312:26-40.

Bakevich, B. D., C. L. Pierce, and M. C. Quist. 2015. Status of the Topeka shiner in west-central Iowa. American Midland Naturalist 174:350-358.

More Publications...

Area of Expertise: 
Aquatic Ecology
B.S., Mankato State, 1980
M.S., Kentucky, 1982
Ph.D., Maryland, 1987
338 Science II