My primary research interests are in ichthyology and marine ecology with emphasis on the biology of exploited estuarine and marine fishes. Much of my research addresses specific questions or fills specific biological gaps necessary for management of fisheries resources, especially elasmobranch fishes. As a primary tool, I use fishery-independent survey methods to study population dynamics, life histories, and distribution patterns of fishes. I also use conventional mark-recapture studies and modern telemetry techniques to acquire data on movement patterns, habitat use, residency and philopatry. A principal goal of this line of research is to delineate essential and vulnerable habitats, especially in estuaries and nearshore marine environments. For example, my work in Virginia led to the federal designation of a Habitat Area of Particular Concern (HAPC) for juvenile sandbar sharks in the lower Chesapeake Bay, a highly vulnerable area that serves as a primary and secondary nursery for this large coastal species. While my work in these areas has primarily involved coastal sharks, I have been involved in projects that included diverse taxa such as estuarine teleosts and terrestrial reptiles.
I also have immense interest in the biology of pelagic and deepwater fishes. Areas of research have included the behavioral and trophic ecology of tropical tunas, the relationship between intermediate seamounts and pelagic predators, the impact of industrial-scale fisheries on the trophic dynamics of pelagic ecosystems, and the role of mesopelagic communities in oceanic ecosystems. My deepwater research is in its infancy but includes studies of life histories, reproductive biology, and movement patterns of elasmobranchs associated with island and continental slopes. I currently have projects in the central Pacific, western Atlantic, and Caribbean investigating various aspects of the biology of bluntnose sixgill sharks (Hexanchus griseus), bigeye sixgill sharks (H. nakamurai), deepwater stingrays (Plesiobatis daviesi), and short-spined spurdogs (Squalus mitsukurii).