New Technology Reveals Habitat Use by Caribbean Sharks
December 06, 2005
Contacts: Francine Bobroff, 305-421-4163, 305-494-4511 (cell)
MIAMI, FL ~~ Important new research by marine scientists, including Dr. Ellen Pikitch of the Pew Institute for Ocean Science, has implications for policy that will improve the conservation of Caribbean sharks. Two related publications in the Marine Technology Society Journal and Marine Ecology Progress Series document findings of the five-year-long Glover's Reef Shark Survey, revealing important information about habitat use and movement patterns of sharks in the Caribbean. Until these studies, virtually nothing had been known about the status and biology of Caribbean sharks. "Sharks are critically important to the health of entire ecosystems, and to protect them we must understand their habitat needs and population status," says Dr. Pikitch, who directs the Pew Institute for Ocean Science at the University of Miami Rosenstiel School of Marine and Atmospheric Science. â€œOur research provides a great deal of information about how different species of sharks use and move about a protected area. We can use these findings to plan marine refuges so they truly protect endangered species.â€
North Atlantic shark populations have declined precipitously in the last few years alone. Fisheries to supply the vast and highly lucrative global shark-fin trade are now expanding into the Caribbean Sea, and coastal areas are undergoing rapid development throughout Central America. Together, these pressures heighten the urgency of developing and implementing a comprehensive conservation and fisheries management plan to conserve the sharks of this region. The Glover's Reef research shows that technology can be employed cost-effectively to identify critical shark habitats, providing the basis for well-designed marine reserves that can protect these ancient predators and their ecosystems.
Glover's Reef, a large and relatively healthy coral atoll off the eastern coast of Belize, is a marine reserve that includes a number of different types of habitat (e.g. shallow lagoon, deep lagoon, ocean reef) and is frequented by sharks. Over the past five years, the scientists of the Glover's Reef Shark Survey collected and studied almost 300 individuals from 9 species of sharks and 3 species of rays. They found sharp differences in preferred habitats between species, as well as between different age groups of the same species. Using automated acoustic telemetry (a system of underwater devices that track the sharks and rays through transmitters carried by the animals), they determined that individual nurse and Caribbean reef sharks showed strong preferences for particular locations ("site fidelity") and appear to be residents of the atoll for extended periods. â€œOur surveying and tracking work provides an important framework for site-selection, sizing and zoning of marine reserves that will help protect these ecologically important reef sharks,â€ says coauthor Demian Chapman of The Guy Harvey Research Institute.
Research methods of the Glover's Reef Shark Survey combine systematic fishing efforts guided by native Belizeans with cutting-edge technology that ranges from DNA-analysis to satellite tracking tags. DNA samples, which were taken from Caribbean reef sharks, southern stingrays, and nurse sharks, have provided new information on the population structure of these species throughout the Caribbean. Moreover, DNA analysis has confirmed the discovery of shark species never before recorded in the region.
As coauthor Dr. Elizabeth Babcock points out, "Glover's Reef serves as a nursery habitat for young sharks. We captured several female sharks that were close to giving birth, as well as newborn and juvenile lemon, nurse, and Caribbean reef sharks. It is very likely that many other unexplored oceanic atolls and inshore areas along this Barrier Reef also support shark breeding grounds, which highlights how much more research and conservation is needed to protect this relatively pristine region."
Ellen K. Pikitch, Demian D. Chapman, Elizabeth A. Babcock, and Mahmood S. Shivji: Habitat use and demographic population structure of elasmobranchs at a Caribbean atoll (Glover's Reef, Belize). Marine Ecology Progress Series 302:187â€“197, 2005.
Demian D. Chapman, Ellen K. Pikitch, Elizabeth A. Babcock, and Mahmood S. Shivji:
Marine reserve design and evaluation using automated acoustic telemetry: A case-study involving coral reef-associated sharks in the Mesoamerican Caribbean. Marine Technology Society Journal 39(1): 42-55, 2005.
This project was funded by the Pew Charitable Trusts through a Pew Fellowship grant to Ellen Pikitch, the Wildlife Conservation Society, the Oak Foundation, a National Science Foundation Fellowship to Demian Chapman, and the Seastar Foundation.
The Guy Harvey Research Institute (GHRI) conducts high quality, solution-oriented basic and applied scientific research needed for effective conservation, biodiversity maintenance, restoration, and understanding of the world's wild fishes. The GHRI also provides advanced scientific training to US and international students who will serve as future stewards of the health of our oceans.
The Pew Institute for Ocean Science is dedicated to conducting, sponsoring, disseminating, and promoting world-class scientific activity aimed at protecting the world's oceans and the species that inhabit them. Established in October of 2003 in partnership with the University of Miami Rosenstiel School for Marine and Atmospheric Science, the Institute is funded by the Pew Charitable Trusts and other philanthropic individuals and organizations.