Tim O’Donnell

Research Scientist I

Tim O’Donnell is a researcher focusing on addressing critical issues related to the health and management of fisheries 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 fish species. Tim has a M.S. in marine biology from the College of Charleston, where he studied the genetic population structure of spotted seatrout off the southeastern U.S coast.

Tim’s interests in the marine environment and molecular biology were piqued while earning his B.S. in wildlife and fisheries science and researching symbiotic organisms in tropical corals using molecular techniques at Penn State. When not at work, Tim enjoys cooking, fishing, hiking, and cheering on the Nittany Lions on the gridiron.


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

Research Interests

Finfish and shellfish are incredibly valuable, both commercially and culturally, on local, regional, and global levels. My passion is to preserve those values by promoting sustainable fisheries using cutting-edge science.

The focus of my research is to investigate fundamental aspects of fish populations using advanced molecular techniques. Using genomic sequencing, we can understand genetic population structure, diversity, and effective population size, which are all critical for the accurate assessment and sustainable management of fish stocks.

Additionally, we use environmental DNA (eDNA) to learn about the spatial and temporal distribution of important species and how they might interact with anthropogenic activities and changing ocean conditions. Molecular techniques can help us understand the prevalence and impact of disease and viral pathogens on populations, and generate estimates for population census size.

We strive to push molecular technology forward by creating innovative tools that can efficiently and accurately provide data-driven insights into critical aspects of fisheries biology and assessment. Using these tools will help us learn more about fish populations and ensure that they are here for decades to come.

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