Hammerhead sharks are recognized as species of conservation concern. The great hammerhead and scalloped hammerhead are both large-bodied, highly mobile, coastal-pelagic sharks with circumtropical distribution. Both species are target or by-catch species in a variety of fisheries throughout their range, and as a result, substantial population declines have occurred in many areas. The International Union for the Conservation of Nature (IUCN) Red List categorizes both species as Critically Endangered. Successful management of these species requires detailed information on their movement and distributions. Generating such information for large-bodied sharks is challenging, however, as they typically move over long distances.
The Project
In the U.S. Atlantic, both species are caught in commercial fisheries. Due to their high at-vessel and post-release mortality, traditional management methods such as prohibited landings are expected to show limited conservation success. Therefore, alternative management strategies are needed. In collaboration with scientists from the Bimini Sharklab, NOAA and Florida State University, we aim to analyze fishery capture data of hammerhead sharks in conjunction with tracking data on space and habitat use. The project uses satellite and acoustic telemetry in combination with fishery dependent and independent data to examine the efficiency of potential time-area closures as a strategy for the conservation of great and scalloped hammerheads in the U.S. Atlantic and the Gulf of Mexico.
The Impact
It is essential that despite demands for food security, fisheries are kept at sustainable levels to safeguard the ecological function of large marine predators. Novel management methods are required to ensure the future of fisheries and the communities that depend on them, as well as the survival of wild populations. This project will provide data to government fisheries managers on the effectiveness of time-area closures as a tool to reduce hammerhead shark mortality from commercial fisheries.