Tim O’Donnell

Research Scientist I

Tim O’Donnell is a freshwater and marine fish researcher with an emphasis on answering applied fisheries questions using molecular tools. He comes to GMGI from Charleston, SC where he worked at the South Carolina Department of Natural Resources as a wildlife biologist concentrating on population genetics in a variety of commercially and recreationally important estuarine and marine fish species. Prior to his employment at the SCDNR, Tim earned his M.S. in marine biology at the College of Charleston studying the spatial and temporal genetic population structure of spotted seatrout off the coast of the southeastern United States. Tim’s interest in molecular biology and the marine environment was piqued during his undergraduate studies at Penn State where he earned his B.S. in wildlife and fisheries science and independently researched endosymbiont communities in tropical corals using molecular techniques. When not at work, Tim enjoys cooking, fishing, hiking, and cheering on the Nittany Lions on the gridiron.


978.879.4575 ext 211


Research Interests

Finfish and shellfish are incredibly valuable both commercially and culturally on local, regional, and global levels. My research interests derive from a passion to preserve the value of our fisheries by using cutting-edge science to answer important questions.

The focus of my research is to investigate fundamental aspects of fish populations using advanced molecular techniques. Using genomic sequencing, we can better understand things like stock structure, genetic diversity, and effective population size, which are important for evaluating the status of our fisheries. Using environmental DNA techniques, we can learn about the spatial and temporal distribution of important species and how they might interact with anthropogenic activities. Molecular techniques can help us understand the prevalence and impact of disease and viral pathogens on populations and generate estimates for population census size. Using these tools will help us learn more about fish populations and ensure that they are here for years to come.


2010 – BSc Wildlife and Fisheries Science, Penn State University
2013 – MS Marine Biology, College of Charleston, Advisor: Tanya L. Darden

Prior Positions

2013-2019: Wildlife Biologist II, Marine Resources Research Institute, South Carolina Department of Natural Resources, Charleston, SC

Research Profile Links

Tim’s Google Scholar Profile

Tim’s ResearchGate Profile

Research Projects


O’Donnell, T.P., & T.J. Sullivan. 2021. Low-coverage whole-genome sequencing reveals molecular markers for spawning season and sex identification in Gulf of Maine Atlantic cod (Gadus morhua, Linnaeus 1758). Ecology and Evolution 11: 10659-10671. doi:10.1002/ece3.7878

O’Donnell, T.P., M.J.M Reichert, and T.L. Darden. 2019.  Genetic population structure of white grunt in the southeastern United States. North American Journal of Fisheries Management 39(4): 725-737. doi: 10.1002/nafm.10306

Underwood, E.B., T.L. Darden, T.P. O’Donnell, and P.R. Kingsley-Smith. 2019.  Population genetic structure and diversity of the invasive island apple snail, Pomacea maculataIa (Perry, 1810), in South Carolina and Georgia, USA. Journal of Shellfish Research 38(1): 163-175. doi: 10.2983/035.038.0115

Montie, E.W., M. Hoover, C. Kehrer, J. Yost, K. Brenkert, T.P. O’Donnell, and M.R. Denson. 2017.  Acoustic monitoring indicates a correlation between calling and spawning in captive spotted seatrout (Cynoscion nebulosus) PeerJ 5: e2944. doi: 10.7717/peerj.2944

Montie, E.W., C. Kehrer, J. Yost, K. Brenkert, T.P. O’Donnell, and M.R. Denson. 2016.  Long-term monitoring of captive red drum Sciaenops ocellatus reveals that calling incidence and structure correlate with egg deposition. Journal of Fish Biology 88:1776-1795. doi: 10.1111/jfb.12938

O’Donnell, T.P., S.A. Arnott, M.R. Denson, and T.L. Darden. 2016.  Effects of cold winters on the genetic diversity of an estuarine fish, the spotted seatrout. Marine and Coastal Fisheries 8:263-276. doi: 10.1080/19425120.2016.1152333

O’Donnell, T.P., M.R. Denson, and T.L. Darden. 2014.  Genetic population structure of spotted seatrout (Cynoscion nebulosus) along the south-eastern U.S.A. Journal of Fish Biology 85:374-393. doi: 10.1111/jfb.12419