UCF Biology Faculty

Research Interests

Dr. Worthy’s research interests relate to understanding the physiological ecology of marine mammals through the study of their bioenergetics, feeding ecology, and habitat utilization. The goal of the Physiological Ecology and Bioenergetics Lab (PEBL) is to better understand how marine ecosystems function, and ultimately examine the health of those systems, by exploring relationships between different species, predator-prey interactions, and how species respond to natural and anthropogenic perturbations. His research program integrates laboratory and field based investigations in an attempt to elucidate the capabilities of different species to withstand normal seasonal variation in their environment. He is also interested in integrating lab and field information to more appropriately define suitable criteria for the husbandry of animals in captivity. His program includes ongoing investigations into the life history and physiological ecology of manatees, cetaceans, and pinnipeds at study sites around the world. Current research interests center around examining the feeding ecology and physiological requirements of marine mammals and how the availability and quality of food impacts their survival and growth. The Worthy lab is currently involved in studies investigating the thermoregulatory capabilities, water balance, feeding ecology, and free-ranging energetics of several important species of marine mammals using techniques such as indirect calorimetry, proximate composition analysis of prey, doubly-labeled water energetics, carbon/nitrogen isotope analysis, and fatty acid signature analysis, amongst others.

Selected Publications

Witteveen, B.H., G.A.J. Worthy, and J.D. Roth. 2009. Tracing migratory movements of breeding North Pacific humpback whales using stable isotope analysis. Marine Ecology Progress Series. In press.
Alves-Stanley, C.D. and G.A.J. Worthy. 2009. Carbon and nitrogen stable isotope turnover rates and diet-tissue discrimination in Florida manatees (Trichechus manatus latirostris). Journal of Experimental Biology 212:2349-2355.
Witteveen, B.H., G.A.J. Worthy, K.M. Wynn, and J.D. Roth. 2009. Population structure of North Pacific humpback whales on their feeding grounds revealed by stable carbon and nitrogen isotope ratios. Marine Ecology Progress Series 379:299-310.
Reich, K. and G.A.J. Worthy. 2006. An isotopic assessment of the feeding habits of free-ranging manatees. Marine Ecology Progress Series 322:303-309.
Smith, H.S. and G.A.J. Worthy. 2006. Stratification and intra- and inter-specific differences in fatty acid composition in common dolphin (Delphinus sp.) blubber. Comparative Biochemistry and Physiology, Part B 143: 486-499.
Ortiz, R.M. and G.A.J. Worthy. 2006. Body composition and water turnover rates of bottle-fed West Indian manatee (Trichechus manatus) calves. Aquatic Mammals 32:41-45.
Samuel, A.M. and G.A.J. Worthy. 2004. Variability in fatty acid composition of bottlenose dolphin (Tursiops truncatus) blubber as a function of body site, season, and reproductive status. Canadian Journal of Zoology 82:1933-1942.
Ortiz, R.M. and G.A.J. Worthy. 2004. Could lower body fat mass contribute to cold-water susceptibility in calves of the West Indian manatee (Trichechus manatus)? Marine Mammal Science 20:176-183.
Kurle, C.M. and G.A.J. Worthy. 2002. Variations in stable carbon and nitrogen isotope ratios in northern fur seal (Callorhinus ursinus) tissues: Implications for dietary and migratory reconstructions. Marine Ecology Progress Series 236:289-300.
Worthy, G.A.J. 2001. Nutrition and energetics. Pages 791-818 in Handbook of marine mammal medicine. Chapter 36. 2nd Edition. L. Dierauf and F. Gulland (eds.). CRC Press, Boca Raton, FL. 1063 p.
Kurle, C.M. and G.A.J. Worthy. 2001. Stable isotope assessment of temporal and geographic differences in the feeding ecology of northern fur seals (Callorhinus ursinus) and their prey. Oecologia 126:254-265.
Ortiz, R.M., D.S. MacKenzie, and G.A.J. Worthy. 2000. Thyroid hormone concentrations in captive and free-ranging West Indian manatees (Trichechus manatus). Journal of Experimental Biology 203: 3631-3637.
Ortiz, R.M. and G.A.J. Worthy. 2000. Effects of capture on adrenal steroid and vasopressin concentrations in free-ranging bottlenose dolphins (Tursiops truncatus). Comparative Biochemistry and Physiology 125A: 317-324.

Highlights

September 2009:

In July, Dr. Graham Worthy, Biology traveled to Haulien, Taiwan to represent UCF at the official signing of a Memorandum of Agreement with Far Glory Ocean Park. This MOA will facilitate joint research activities and the exchange of researchers and open up new opportunities for marine research in Taiwan.

July 2009:

In July, Dr. Graham Worthy was an invited participant in an international symposium on “Developing Conservation Strategies for *Sousa chinensis* in Taiwan” held at National Taiwan University in Taipei. He presented a paper on “The application of stable isotope and fatty acid signature analysis to assessing habitat utilization and feeding habits of *Sousa* in Taiwan” and participated in 2 days of planning sessions.

July 2009:

May 2008:

Steve Shippee (Con Bio PhD) and Dr Graham Worthy received $12,435 from SeaWorld & Busch Gardens Conservation Fund to support Shippee's research on "Changes in habitat use and distribution of bottlenose dolphins in the Choctawhatchee Bay estuary following recent red tide episodes"

Links

The Physiological Ecology and Bioenergetics Lab (PEBL)

Memberships

Director, Physiological Ecology and Bioenergetics Lab (PEBL)