John Tyminski - USF Ichthyology

johnski@mote.org

Current Program: M.S. in Biology

B.S. with Specialization in Marine Biology, University of Guelph, 1991

Research Interests

I have a broad array of research interests which include reproductive physiology, behavioral ecology, feeding ecology, and fisheries biology. Although my early research experience focused on salmonid fishes, the last 10 years of work have been devoted to studying elasmobranchs. My thesis research aims to examine the role of steroid hormones in the reproductive tissues of the male bonnethead shark (Sphyrna tiburo). Specifically, I am developing an RNA probe to evaluate the expression patterns of androgen receptors (AR) both ontogenetically and seasonally in the testes, epididymides, seminal vesicles, and claspers of male bonnetheads. Molecular methods such as in situ hybridization and northern blotting will be utilized to evaluate the cellular location and relative levels of AR gene expression. Because elasmobranchs are the oldest living animals to possess an archetypical vertebrate pattern of reproductive endocrinology, this study may provide insight into the evolution of steroid hormone receptors.

Research Experience

Since joining the Center for Shark Research at Mote Marine Laboratory in 1995, I have had the opportunity to work on a diverse range of projects involving a broad array of shark and ray species. Here are a few of the specific projects that I have been involved in:
• Blacktip shark relative abundance surveys along Florida’s Gulf coast
• Characterization of the shark nursery areas of Florida’s coastal waters
• A survey of the artisanal elasmobranch fishery of the Sea of Cortez
• Endocrine disruption as a possible cause of infertility in the bonnethead shark
• Diet, feeding chronology, and gastric evacuation rates in the bonnethead shark
• Movement and migration studies of blacktip sharks in Mexico and Texas
• Behavior ecology of the whale sharks of Mexico’s Yucatan Peninsula

Selected Publications and Abstracts

• Kajiura S.M., Tyminski J.P, Forni J.B., and Summers A.P. 2005. The sexually dimorphic cephalofoil of bonnethead sharks, Sphyrna tiburo. Biological Bulletin. 209:1-5.

•Hueter, R.E., Manire C.A, Tyminski J.P., Hoenig J.M., and Hepworth D.A. Assessing mortality of released or discarded fish using a logistic model of relative survival derived from tagging data. Transactions of the American Fisheries Society. In Press.

•Hueter, R.E., Castillo B Géniz J.L. , Márquez B Farias J.F., and Tyminski J.P. The use of Laguna Yalahau, Quintana Roo , Mexico as a primary nursery for the blacktip shark (Carcharhinus limbatus). In: C.T. McCandless, N.E. Kohler, and H.L. Pratt, Jr., editors. Shark nursery grounds of the Gulf of Mexico and the East Coast waters of the United States. Special Publication of the American Fisheries Society. In press.

•Hueter, R.E. and Tyminski J.P.. Species-specific distribution and habitat characteristics of shark nurseries in Gulf of Mexico waters off peninsular Florida and Texas . In: C.T. McCandless, N.E. Kohler, and H.L. Pratt, Jr., editors. Shark nursery grounds of the Gulf of Mexico and the East Coast waters of the United States. Special Publication of the American Fisheries Society. In press.

•Hueter, R.E., Gonzalez J.C., Remolina F.S., De la Parra R., Tyminski J.P., and Perez Ramirez J. Whale shark summer feeding grounds where the Gulf of Mexico meets the Caribbean Sea . American Elasmobranch Society Annual Meeting. Tampa , FL.

•Tyminski, J.P , Hueter R.E., and Simpfendorfer C.A. Relative abundance and long-term movement patterns of juvenile blacktip sharks, Carcharhinus limbatus, in three Florida Gulf coastal nursery areas, 1995-2004. American Elasmobranch Society Annual Meeting. Tampa , FL.

•Wiley, T.R., Simpfendorfer C.A. , and Tyminski J.P. Elasmobranchs of Everglades National Park . American Elasmobranch Society Annual Meeting. Tampa , FL.

• Hueter R.E., Castillo-Geniz J.L, Marquez-Farias J.F., and Tyminski J.P., 2003. “Investigations of a primary nursery area for the blacktip shark, Carcharhinus limbatus, in Quintana Roo, Mexico.” American Society of Ichthyologists and Herpetologists Annual Meeting, Manaus, Brazil.

• Gelsleichter J., Rasmussen L.E.L., Manire C.A., Tyminski J., Chang B., and Lombardi-Carlson L., 2002. ”Serum steroid concentrations and development of reproductive organs during puberty in male bonnethead sharks Sphyrna tiburo.” Fish Physiology and Biochemistry. 26:389-401.

• Hueter R.E, and Tyminski, J.P., 2002. U.S. Shark Nursery Research Overview, Center for Shark Research, Mote Marine Laboratory 1991-2001. Final Report submitted to NOAA/NMFS, Narragansett, RI. Mote Marine Laboratory Technical Report No. 816.

• Tyminski J.P., Simpfendorfer C., Manire C.A., and Hueter, R.E., 2001. “Growth rates of bonnethead sharks, Sphyrna tiburo, from the west coast of Florida estimated from tag-recapture data.” American Society of Ichthyologists and Herpetologists Annual Meeting State College, PA.

• Tyminski J.P., Neer J.A., and Jones E.M., 2001. “Nursery areas, revised sizes at maturity, and range extensions: findings from the Gulf of California artisanal elasmobranch fishery.” American Society of Ichthyologists and Herpetologists Annual Meeting, La Paz, Mexico.

• Tyminski J.P., Cortés E., Manire C.A., and Hueter R.E., 1999. “Gastric evacuation and estimates of daily ration in the bonnethead shark Sphyrna tiburo.” American Society of Ichthyologists and Herpetologists Annual Meeting, State College, PA.

• Tyminski J.P., Cook S.J., and Hueter R.E., 1997. “Development of an external coating to reduce biofouling of fish dart tags,” American Fisheries Society Florida Chapter Annual Meeting, Brooksville, FL.