Combining genetic assessments of NSU and South Carolina researchers shows that at least 7 percent of the sharks in U.S. waters originally thought to be scalloped hammerheads turned out to be the new species. This means that the population of the endangered real scalloped hammerhead in U.S. waters is probably smaller than originally thought.
The status of the scalloped hammerhead (Sphyrna lewini) is currently under review by the U.S. National Marine Fisheries Service to determine if it warrants listing as threatened or endangered under the U.S. Endangered Species Act. It's already on the red list of endangered species of the International Union for Conservation of Nature and Natural Resources (IUCN). The new species is on neither list.
"We hope that during this important scalloped hammerhead status review, the new look-alike species will be recognized, and possible impacts of historical mix-ups between the two species on past scalloped hammerhead stock assessments will be considered," says Shivji.
According to Danillo Pinhal, Ph.D., an assistant professor at the UNESP-So Paulo State University in Brazil who performed the lab work as a visiting graduate student in Shivji's laboratory in 2009, "the finding of this species all the way down in Brazilian waters, where hammerhead sharks are heavily fished, raises concerns about the population status of both species not just in U.S. waters but throughout the western Atlantic. It's an international issue now and it's essential that further research on this new species be conducted in Brazilian waters."
Other than differences in their DNA, the two shark species also differ in their number of vertebrae. The new look-alike species has approximately 20 fewer vertebrae than the
|Contact: Ken Ma|
Nova Southeastern University