My research combines molecular and field-based approaches to better understand the population biology, evolution and ecology of large marine vertebrates, particularly sharks and their relatives. Projects are designed to answer interesting biological questions and often address pressing conservation issues. I also develop resources to aid in wildlife forensics applications, in particular for monitoring the global shark fin trade.
One focus of my research is to better understand how genetic variation within marine fish species is partitioned across the seascape. I am especially interested in elucidating the behavioral processes underpinning genetic population structure, in particular the tendency of individuals to remain within or return to the place where they were born. This type of research is also useful for delineating management units, scaling management interventions and as a basis for sourcing wildlife products in trade back to their geographic area of origin. My students and I have recently focused on using information about the genetic diversity of wild marine fish populations to make inferences about the effective number of breeding adults, inbreeding levels and population trajectories.
DNA-analysis is also very useful for elucidating the reproductive biology of species that are not amenable to sustained field observation. I am currently using DNA-analysis to better understand the evolution of mating systems in a variety of sharks and their relatives. I recently discovered that female sharks are able to reproduce without sex (parthenogenesis or â€œvirgin birthâ€). This finding was reported in over 1100 media venues worldwide.
Outside of the genetics laboratory I use acoustic and satellite telemetry to better understand the movements of sharks and other large fish in relation to protected areas (e.g. marine reserves) and potential threats. I am involved in tracking projects in Belize (Caribbean reef and nurse sharks), the Bahamas (lemon, oceanic whitetip and great hammerhead sharks) and along the U.S. eastern seaboard from Long Island to Florida (e.g. lemon, bull and great hammerhead sharks; Atlantic sturgeon). This research is useful for defining essential fish habitat, for revealing migratory patterns and for designing marine reserves that will more effectively contribute to the conservation of these animals. My research group has also combined these tracking studies with remote-video based surveys of reef shark abundance to directly assess the effectiveness of marine reserves for these species. My research and outreach efforts in these areas have contributed to the establishment of marine reserves in Belize and The Bahamas.
My research group also develops resources for wildlife forensics applications, with a particular focus on the international dried shark fin trade. We have developed DNA tests to identify the species-of-origin of shark and sawfish body parts in trade, some of which have proven sensitive enough to tell us the species present in shark fin soup. Debra Abercrombie and I have recently developed a guide to help customs and enforcement personnel from all over the world to identify the fins from five shark species of particular conservation concern (see www.sharkfinid.org). These resources were an integral part of successful proposals to list these species on the Convention on International Trade in Endangered Species (CITES) in March 2013.