Researchers at the University of Miami (UM) Rosenstiel School of Marine and Atmospheric Science published new findings that suggest the expansion of protected areas into U.S. federal waters would safeguard 100 percent of core home range areas used by three species of sharks tracked in the northwestern Atlantic Ocean. The study investigated the core home range of 86 bull, great hammerhead and tiger sharks tagged in waters off south Florida and the northern Bahamas to understand if these highly mobile shark species might benefit from spatial protection, such as marine protected areas (MPAs). The team examined shark movements in core habitat use areas, or CHUAs, where the sharks were spending the majority of their time, in relation to zones that prohibited fishing or were these sharks were already fully protected within areas of the U.S. and Bahamas exclusive economic zones (EEZs).

"There are concerns that spatial protections may not benefit large sharks since they are highly mobile and likely to regularly move in and out of MPAs," said study co-author Neil Hammerschlag, a research assistant professor at the UM Rosenstiel Marine School and UM Abess Center for Ecosystem Science and Policy. "While it's not feasible to protect highly mobile species wherever they go, our findings suggest that significant conservation benefits can be achieved if they are protected in areas where they spend the majority of their time, such as their core habitat use areas."

The results show that none of the tracked bull shark's regional CHUAs were in areas that are fully protected from fishing, and for the great hammerhead and tiger sharks tracked, only 18 percent and 35 percent, respectively, of their core use areas were currently protected. The study also found that the majority of the CHUAs utilized by all three shark species were within the U.S. EEZ.

"Our results will help enable policy makers to make more informed decisions when developing conservation plans for these species, particularly when considering a place-based management approach," said UM Rosenstiel School alumna Fiona Graham, the lead author of the study.