Areas of Expertise
Teaching Responsibilities: General Biology I and III, Endocrinology, Health Effects of Environmental Pollutants, Environmental Toxicology, Ecology of Sharks, Aquatic Toxicology (graduate), Critical Skills in Science (graduate)
Research Interests: shark biology, hormone function, reproduction, toxicology, pollution
B.S. (Marine Science), Eckerd College, (1990)
Ph.D. (Marine Science), The College of William and Mary in Virginia, (1998)
My research focuses on the physiological factors that regulate development and reproduction in aquatic vertebrates with special emphasis on the endocrine system. I also conduct research on the effects that environmental pollution may have on these essential processes. The overall goals of my research program are to determine how reproductive adaptations contribute to the growth and stability of aquatic vertebrate populations, and how alterations in the reproductive biology of aquatic vertebrates caused by environmental contaminants can lead to population decline.
The majority of my research is conducted on sharks and rays, fishes that have received far less attention in the fields of endocrinology and ecotoxicology than most other vertebrate groups. However, I also conduct research on pollutant exposure and effects in bony fish and marine mammals. I have a long history of student involvement in my research projects, and encourage both undergraduate and graduate students who are interested in participating in my research to contact me.
My research lab currently focuses on the following research themes:
Identification of Shark Essential Fish Habitat in Northeast Florida Waters: As part of the Cooperative Atlantic States Shark Pupping and Nursery (COASTSPAN) Survey Program, the UNF Shark Biology Program examines the species composition, abundance, distribution, and movement patterns of shark populations in northeast Florida waters. This work currently focuses on three regions: 1) Cumberland Sound, 2) Nassau Sound, and 3) portions of the Atlantic Intracoastal Waterway near Jacksonville and St. Augustine (for example, the Tolomato River). The goal of this research is to identify areas that are in need of special consideration and, in some cases, protection because they serve as essential habitat for ecologically and economically important and federally regulated shark species. I also use these collections as a resource for samples used in my other studies on pollutant exposure/effects and reproduction.
Pollutant Exposure & Effects in Sharks and Rays on the U.S. East Coast: I will be continuing to study exposure levels and effects of environmental pollutants in shark and ray populations from the U.S. east coast, with special emphasis on emerging contaminants of concern, such as human pharmaceuticals and personal care products. The goal of this research is to determine if shark populations residing in areas identified as “essential habit” are exposed to health-threatening levels of aquatic toxins or pollutants and are exhibiting signs of pollutant effects. Since little research has been conducted on pollutant effects in sharks and rays, much of this work focuses on the development of techniques used to identify pollutant-specific effects in these animals. Given the threatened status of many shark populations, I place special emphasis on the development of non-lethal tools for examining pollutant exposure and effects in sharks and rays. Several of these techniques are also being applied to other threatened or federally protected wildlife, such as the Florida manatee and Cook Inlet beluga whales.
Reproduction in sharks and other aquatic vertebrates: I also intend to continue my research on the hormonal regulation of reproduction in sharks and rays, with new emphasis on the development and/or refinement of non-lethal tools for examining the reproductive biology of these animals. For example, my collaborators and I are preparing to begin a multi-year study on the reproductive biology of the endangered smalltooth sawfish (Pristis pectinata), in which we will use plasma sex hormone profiles to determine size-at-maturity and reproductive seasonality of this species. A similar collaborative study will use sex hormone profiles to determine maturity status and reproductive stage of the threatened alligator gar, Atractosteus spatula.
Publications & Presentations
Gelsleichter, J., Szabo, N.J., Belcher, C.N., Ulrich, G.F. 2008. Organochlorine contaminants in bonnethead sharks (Sphyrna tiburo) from Atlantic and Gulf estuaries on the U.S. east coast. Mar. Pollut. Bull. 56: 359-363.
Bethea, D.M., Hale, L., Carlson, J.K., Cortés, E., Manire, C.A., Gelsleichter, J. 2007. Latitudinal variation in the diet and daily ration of the bonnethead shark, Sphyrna tiburo, from the eastern Gulf of Mexico. Mar. Biol. 152:1009-1020.
Gelsleichter, J., Szabo, N.J., and Morris, J.J. 2007. Organochlorine contaminants in juvenile sandbar (Carcharhinus plumbeus) and blacktip (Carcharhinus limbatus) sharks from major nursery areas on the east coast of the United States. Submitted for publication in Shark Nursery Grounds of the Gulf of Mexico and East Coast waters of the United States. (C. McCandless, N. Kohler, and H.L. Pratt, Jr., eds). American Fisheries Society symposium 50: 153-164.
Gelsleichter, J., Walsh, C.J., Szabo, N.J., and Rasmussen, L.E.L. 2006. Organochlorine concentrations, reproductive physiology, and immune function in unique populations of freshwater Atlantic stingrays (Dasyatis sabina) from Florida’s St. Johns River. Chemosphere. 63: 1506-1522.
Piercy, A.P., Gelsleichter, J., and Snelson, F.F. 2006. Morphological changes in the clasper gland of the Atlantic stingray, Dasyatis sabina, associated with the seasonal reproductive cycle. J. Morph. 267:109-114.
McComb, D.M., Gelsleichter, J, Manire, C.A., and Brown, C.L. 2005. Geographic variation in maternal provisioning of thyroid hormones in egg yolk of embryonic bonnethead sharks (Sphyrna tiburo). Gen. Comp. Endocrinol. 144: 167-173.
Gelsleichter, J., Manire, C.A., Szabo, N.J., Cortés, E., Carlson, J., and Lombardi-Carlson, L. 2005. Organochlorine concentrations in bonnethead sharks (Sphyrna tiburo) from four Florida estuaries. Arch. Environ. Contam. Toxicol. 48: 474-483.
Chapman, D.D., Prodöhl, P.A., Gelsleichter, J., Manire, C.A., and Shivji, M.S. 2004. Molecular insights into shark mating systems: Predominance of genetic monogamy by females in the hammerhead Sphyrna tiburo (Carcharhiniformes, Sphyrnidae). Mol. Ecol. 13:1965-1974.
Gelsleichter, J. 2004. Hormonal regulation of elasmobranch physiology. Pages 287-323 in Biology and Ecology of Sharks and Their Relatives. (J. Carrier, J. Musick and M. Heithaus, eds.). CRC Press, Boca Raton, FL.
Gelsleichter, J., Rasmussen, L.E.L. Manire, C.A., Tyminski, J., Chang, B., and Lombardi-Carlson, L. 2002 (Published in 2004). Serum steroid concentrations and development of the reproductive system during puberty in male bonnethead sharks, Sphyrna tiburo. Fish Physiol. Biochem. 26: 389-401.