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Seminar: "Where's home? Applying Genetic Tools to Resolve Marine Turtle Spatial Ecology and Reproductive Behavior"

Assistant Research Scientist

Contact Information

Pictured: Dr. Brian Shamblin

Contact Dr. Brian Shamblin


Campus address

Warnell 3-301


Research Areas Detail:

My research focuses on the application of genetic tools to inform management and conservation. Much of this work has addressed knowledge gaps in marine turtle life history. Marine turtle populations are defined based on female natal homing, but the scale of this homing behavior is often difficult to infer due to poor marker resolution. We have refined assessments of population structure and migratory connectivity in western Atlantic loggerhead and green turtles through application of mitogenomic markers. Physical tagging and satellite telemetry projects have made seminal contributions to our understanding of marine turtle reproductive ecology, but many aspects remain unresolved. I developed a clutch sampling approach to identify individuals females without the need to physically interact with them, which has permitted genetic tagging on a scale that would not be feasible using traditional tagging methods. We use these genetic tagging data in a capture-recapture framework to better understand the reproductive ecology of Northern Recovery Unit loggerhead turtles. This work includes characterizing site fidelity and nest site selection as well as refining estimates of adult female population size, survival, and reproductive parameters. 

Recent Citations:

Shamblin BM, Hart KM, Martin KJ, Ceriani SA, Bagley DA, Ehrhart LM, Nairn CJ (2020) Green turtle mitochondrial microsatellites indicate finer-scale natal homing to isolated islands than to continental nesting sites. Marine Ecology Progress Series 643: 159-171.

Pfaller JB, Pajuelo M, Vander Zanden HB, Andrews KA, Dodd MG, Godfrey MH, Griffin DB, Ondich BL, Pate SM, Williams KL, Shamblin BM, Nairn CJ, Bolten AB, Bjorndal KA (2020) Identifying patterns in foraging-area origins in breeding aggregations of migratory species: Loggerhead turtles in the Northwest Atlantic. PLoS One 15:e0231325.

Tumas HR, Shamblin BM, Woodrey MS, Nairn CJ (2019) Broad-scale patterns of genetic diversity and structure in a foundational salt marsh species, black needlefish (Juncus roemerianus). Conservation Genetics 20: 903-915. 

Pfaller JB, Williams KL, Frick MG, Shamblin BM, Nairn CJ, Girondot M (2019) Genetic determination of tag loss dynamics in nesting loggerhead turtles: a new chapter in the "tag loss problem." Marine Biology 166: 97. 

Shamblin BM, Godfrey MH, Pate SM, Thompson WP, Sutton H, Altman J, Fair K, McClary J, Wilson AM, Milligan B, Stetzar EJ, Nairn CJ (2018) Green turtles at their northern range limit in the United States represent a distinct subpopulation. Chelonian Conservation and Biology 17:314-319.

Tumas HR, Shamblin BM, Woodrey MS, Nibbelink NP, Chandler R, Nairn CJ (2018) Landscape genetics of the foundational salt marsh plant species black needlerush (Juncus roemerianus Scheele) across the northeastern Gulf of Mexico. Landscape Ecology 33:1585-1601.

Shamblin BM, Witherington BE, Hirama S, Hardy RF, Nairn CJ (2018) Mixed stock analyses indicate population-scale connectivity effects of active dispersal by surface-pelagic green turtles. Marine Ecology Progress Series 601:215-226.

Ferrari B, Shamblin BM, Chandler R, Tumas HR, Haché S, Reitsma L, Nairn CJ (2018) Canada Warbler (Cardellina canadensis): novel molecular markers and a preliminary analysis of genetic diversity and structure. Avian Conservation and Biology 13:8.

Shamblin BM, Dodd MG, Griffin DB, Pate SM, Godfrey MH, Coyne MS, Williams KL, Pfaller JB, Ondich BL, Andrews KM, Boettcher R, Nairn CJ (2017) Improved female abundance and reproductive parameter estimates through subpopulation-scale genetic capture-recapture of loggerhead turtles. Marine Biology. 164:138.

Shamblin BM, Dutton PH, Shaver DJ, Bagley DA, Putman NF, Mansfield KL, Ehrhart LM, Peña LJ, Nairn CJ (2017) Mexican origins for the Texas green turtle foraging aggregation: a cautionary tale of incomplete baselines and poor marker resolution. Journal of Experimental Marine Biology and Ecology. 488:111-120.

Komoroske LM, Jensen MP, Stewart KR, Shamblin BM, Dutton PH (2017) Advances in the application of genetics in marine turtle biology and conservation. Frontiers in Marine Science. DOI: 10.3389/fmars.2017.00156.

Shamblin BM, Dutton PH, Bjorndal KA, Bolten AB, Naro-Maciel E, Santos AJB, Bellini C, Baptistotte C, Marcovaldi MÂ, Nairn CJ (2015) Deeper mitochondrial sequencing reveals cryptic diversity and structure in Brazil’s green turtle rookeries. Chelonian Conservation and Biology. 14:167-172.

Shamblin BM, Bagley DA, Ehrhart LM, Desjardin NA, Martin RE, Hart KM, Naro-Maciel E, Rusenko K, Stiner JC, Sobel D, Johnson C, Wilmers TJ, Wright LJ, Nairn CJ (2015) Genetic structure of Florida green turtle rookeries as indicated by mitochondrial control region sequences. Conservation Genetics. 16:673-685.

Naro-Maciel E, Reid B, Alter SE, Amato G, Bjorndal KA, Bolten AB, Martin M, Nairn CJ, Shamblin BM, Pineda-Catalan O (2014) From refugia to rookeries: phylogeography of Atlantic green turtles. Journal of Experimental Marine Biology and Ecology. 461:306-316.

Vander Zanden HB, Pfaller JB, Reich KJ, Pajuelo M, Bolten AB, Williams KL, Frick MG, Shamblin BM, Nairn CJ, Bjorndal KA (2014) Foraging areas differentially affect reproductive output and interpretation of trends in abundance of loggerhead turtles. Marine Biology. 161:585-598.

Shamblin BM, Bolten AB, Abreu-Grobois FA, Bjorndal KA, Cardona L, Carreras C, Clusa M, Monzón-Argüello C, Nairn CJ, Nielsen JT, Nel R, Soares LS, Stewart KR, Vilaça ST, Türkozan O, Yilmaz C, Dutton PH (2014) Geographic patterns of genetic variation in a broadly distributed marine vertebrate: new insights into loggerhead turtle stock structure from expanded mitochondrial DNA sequences. PLOS ONE. DOI: 10.1371/journal.pone.0085956

Shamblin BM, Bolten AB, Bjorndal KA, Dutton PH, Nielsen JT, Abreu-Grobois FA, Reich KJ, Witherington BE, Bagley DA, Ehrhart LM, Tucker AD, Addison DS, Arenas A, Johnson C, Carthy RR, Lamont MM, Dodd MG, Gaines MS, LaCasella E, Nairn CJ (2012) Expanded mitochondrial control region sequences increase resolution of stock structure among North Atlantic loggerhead turtle rookeries. Marine Ecology Progress Series. 469:145-160.

Shamblin BM, Bjorndal KA, Bolten AB, Hillis-Starr ZM, Lundgren I, Naro-Maciel E, Nairn CJ (2012) Mitogenomic sequences better resolve stock structure of southern Greater Caribbean green turtle rookeries. Molecular Ecology. 21:2330-2340.

Courses Regularly Taught:

Seminar: Multi-stakeholder partnerships as a tool for recovering imperiled species...

USGS Georgia Cooperative Fish & Wildlife Unit Leader
Adjunct Professor

Contact Information

Contact Dr. Cecil Jennings


Campus address

Warnell 3-429


Ph.D. Forest Resources Conservation (Fisheries Science) University of Florida, Gainesville, Florida
M.S. Wildlife Ecology (Fisheries Management Option) Mississippi State University, Starkville, Mississippi
B.A. Biology, Natural Science, and Conservation Carthage College, Kenosha, Wisconsin

Prior Positions:
Research Fisheries Biologist - Upper Midwest Environmental Science Center, La Crosse, WI

Fisheries Biologist - Virgin Islands Division of Fish and Wildlife, St. Thomas, VI


Recent Citations:

TenHarmsel, H. J., B. B. Boley, B. J. Irwin, and C. A. Jennings. 2019. An Importance-Satisfaction Analysis of trout license holders in Georgia. North American Journal of Fisheries Management 39(6):1227-1241. doi:10.1002/nafm.10353 

Roop, H. J., N. C. Poudyal, and C. A. Jennings. 2019. Catch and harvest of targeted sportfishes at Marben Public Fishing Area in middle Georgia. Journal of the Southeastern Association of Fish and Wildlife Agencies 6:28-34.

Roop, H. J., N. C. Poudyal, and C. A. Jennings. 2018. Efficacy of a passive use-estimation system for estimating fishing effort on a multi-lake fishery.  Fisheries Management and Ecology 2018;25:512-514.

Roop, H.J., N.C. Poudyal, and C. A. Jennings.  2018. Assessing angler effort, catch, and harvest on a multi-lake fishery in middle Georgia.  North American Journal of Fisheries Management 38:833-841. (DOI) - 10.1002/nafm.10179 —

Jennings, C. A., G. E. Mitchell, C. Nelson. 2018. Seasonal Food Habits of Introduced Blue Catfish in Lake Oconee, Georgia.  Journal of the Southeastern Association of Fish and Wildlife Agencies 5:39-45. —

Parr, R. T., Bringolf, R. B. and Jennings, C. A. 2018. Efficacy of Otoliths and First Dorsal Spines for Preliminary Age and Growth Determination in Atlantic Tripletails. Marine and Coastal Fisheries 10: 71–79. doi:10.1002/mcf2.10008

Sundmark, A. P. and C. A. Jennings. 2017. Influence of lake surface area and total phosphorous on annual bluegill growth in small impoundments of central Georgia.  Southeastern Naturalist 16(4):546-566.

Parr, R.T., C.A. Jennings, N.D. Denslow, K.J. Kroll, and R.B. Bringolf. 2016. Evaluation of reproductive status in Tripletail by traditional and non-lethal approaches.  Marine and Coastal Fisheries: Dynamics, Management, and Ecosystem Science 8(1):16-22.

Homer, M.D., J. T. Peterson, and C. A. Jennings. 2015.  Evaluation of Three Aging Techniques and Back-calculated Growth for Introduced Blue Catfish from Lake Oconee, Georgia.  Southeastern Naturalist 14(4):740–756.

Kellock, K., B. E. Trushel, P. C. Ely, C.A. Jennings, and R. B. Bringolf.  2014. Survey of intersex Largemouth Bass Micropterus salmoides from impoundments in Georgia USA.  Transactions of the American Fisheries Society 143:565-572.

Robinson, K. F. and C.A. Jennings. 2014. Productivity of functional guilds of fishes in managed wetlands in coastal South Carolina.  Journal of Fish and Wildlife Management 5(1):70-86.

Robinson, K.F. and C.A. Jennings.  2014. A comparison of resident fish communities in managed and unmanaged coastal wetlands in North Carolina and South Carolina, USA.  Southeastern Naturalist 13:(2):237-260.

Boone, S. S., S. J. Divers, A. C. Camus, D. L. Peterson, C. A. Jennings, J. L. Shelton, & S. M. Hernandez.  2013.  Pathologic and Physiologic Effects Associated with Long-Term Intracoelomic Transmitters in Captive Siberian Sturgeon (Acipenser baerii).  North American Journal of Fisheries Management 33:869-877.

Boone, S. S., S. M. Hernandez, A. C. Camus, D. L. Peterson, C. A. Jennings, J. L. Shelton & S. J. Divers. 2013.  Evaluation of four suture materials for surgical incision closing in Siberian sturgeon.  Transactions of the American Fisheries Society  142:649-659.

Jennings, C.A., B. L. Sloss, B. A. Lasee, G. J. Burtle, and G. R. Moyer. 2013.  Care, Handling, and Examination of Sampled Organisms.  Pp 163-221 in A. V. Zale, D. L. Parrish, and T. M. Sutton, editors.  Fisheries Techniques 3rd Edition.  American Fisheries Society, Bethesda, MD.Jennings, C. A., T. E. Lauer, and B. Vondracek, Editors. 2012.  Scientific Communication for Natural Resource Professionals.  American Fisheries Society. Bethesda, MD. 180 p.

Jennings, C. A.  2012.  Communicating science: from cuneiform to the contemporary and beyond.  pp 1-6. in C. A. Jennings, T. E. Lauer, and B. Vondracek (editors). Scientific Communication for Natural Resource Professionals. American Fisheries Society. Bethesda, MD. 180 p.

Dennerline, D.E., C.A. Jennings, and D.J. Degan. 2012. Relationships between hydroacoustic derived density and gill net catch: Implications for Fish Assessments. Fisheries Research 123-124: 78-89.

Robinson, K. F. and C. A. Jennings.  2012.  Maximizing Age-0 Spot export form a South Carolina estuary: an evaluation of coastal impoundment management via structured decision making.  Marine and Coastal Fisheries: Dynamics, Management, and Ecosystem Science 4(1):156-172.

Peterson, R. C., C. A. Jennings, and J. T. Peterson. 2012.  River discharge effects on abundance of age-0 redhorses (Moxostoma spp.) in the Oconee River, Georgia, USA, with implications for robust redhorse.  River Research and Application. 29:734-742.

Bonvehcio, T. F. and C. A. Jennings, and D. R. Harrison. 2011.  Diet and population metrics of the introduced blue catfish population in the Altamaha, River, GA.  Proceedings of the Southeastern Association of Fish and Wildlife Agencies 65:112-118.

Belcher, C. N. and C. A. Jennings. 2011. Identification and evaluation of sub-adult shark bycatch in Georgia’s commercial trawl fisheries.  Fisheries Management and Ecology 18:104-112.

Homer, M. D. Jr, and C. A. Jennings. 2011.  Historical catch, age structure, sizes, and relative growth for an introduced population of blue catfish in Lake Oconee, GA.  Pages 383-394 in P. H. Michaletz and V. H. Travnichek, editors.  Conservation, ecology, and management of catfish: the second international symposium.  American Fisheries Society, Symposium 77.  Bethesda, MD

Reinert, T. R. and C. A. Jennings. 2011.  Effect of egg sampling efficiency on estimates of historic striped bass egg production in the Savannah River Estuary, Georgia-South Carolina.  Proceedings of the Annual Conference of Southeastern Association of Fish and Wildlife Agencies 65:71-77.

Belcher, C.N. and Jennings, C. 2010. Utility of Mesohabitat Features for Determining Habitat Associations of Sub-adult Sharks in Georgia's Estuaries. Environmental Biology of Fishes 88:349-359.

Jennings, C. A., E. W. Dilts, J. S. Shelton and R. C. Peterson.  2010.  Fine sediment affects on survival to emergence of robust redhorse.  Environmental Biology of Fishes 87:43-53.

Jennings, C. A., and S. J. Zigler. 2010. Biology and life history of paddlefish in North America: an update.  Pages 1- 22 in C. P. Paukert and G. D. Scholten, Editors.  Paddlefish Management, Propagation, and Conservation in the 21st Century: Building from 20 years of Research and Management.  American Fisheries Society, Symposium 66.  Bethesda, MD.

Courses Regularly Taught: