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article imageNew hammerhead shark double may already be threatened

By Elizabeth Batt     Mar 27, 2012 in Environment
Hollywood - The existence of a new shark species discovered in 2005 is endangering the scalloped hammerhead shark. At the same time scientists say, the shark – almost the hammerhead's double, is itself at risk from shark finning.
According to new research by the Nova Southeastern University Oceanographic Center (NSU-OC) Save Our Seas Shark Center USA, and Guy Harvey Research Institute, a new species of hammerhead is not only more widespread than initially thought, but its presence could be having a negative impact on its look-alike cousin, the scalloped hammerhead.
DNA analysis is estimating the sharks separated from each other approximately 4.5 million years ago, yet the new species – only discovered in 2005 by NSU-OC professor Mahmood Shivji, Ph.D. and his team, has not been named or thoroughly studied. Shivja suggests that without further data on the shark's prevalence, scientists cannot know the impact it has had on its cousin, or whether it too, is vulnerable to the practice of shark finning.
Shivji's team unearthed the existence of the new species in 2005, after examining the DNA of what they believed was a scalloped hammerhead. Independent tests conducted by the University of South Carolina in 2006, also confirmed the new species of shark. Despite similarities to its cousin, researchers said, the "look-alike species has approximately 20 fewer vertebrae than the scalloped hammerhead, in the range of 170 vs. 190."
Concerns were elevated in April 2012 NSU-OC explained, after an article in the scientific journal Marine Biology, revealed the new hammerhead species more than 4,300 miles away near the coast of southern Brazil. This confirmed that the original finding was "not a local oddity" and the new species was much wider spread. As a result, Shivji said:
It’s very important to officially recognize, name and learn more about this new hammerhead species and the condition of its populations through systematic surveys."
Danillo Pinhal, Ph.D., an assistant professor at the UNESP-São Paulo State University in Brazil and former visiting graduate who assisted Shivji in 2009, agreed, adding:
"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."
This new species of hammerhead shark closely mimics the scalloped hammerhead  but has 20 fewer verte...
This new species of hammerhead shark closely mimics the scalloped hammerhead, but has 20 fewer vertebrae.
Studies and genetic assessments by NSU and South Carolina researchers have revealed 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. Their presence in southern Brazil says NSU-OC, "means they may face the same fishery pressures as the real scalloped hammerhead, which is being fished unsustainably for its highly prized fins."
Shivji worries that "long-standing species misidentification" has cast uncertainty on the status of the real scalloped hammerhead which is currently under review by the U.S. National Marine Fisheries Service, and is listed as endangered by the International Union for Conservation of Nature and Natural Resources (IUCN) red list. The new shark species doesn't appear on either list says NSU-OC.
Shivji sees this as a problem. "Without management intervention to curtail its inadvertent killing," Shivji explains, "we run the risk that overfishing could eradicate an entire shark species before its existence is even properly acknowledged."
Nova Southeastern University (NSU) is the eighth largest not-for-profit independent institution nationally with more than 28,000 students. Its Oceanographic Center (OC) is located in Hollywood, Fla., and has offered graduate and undergraduate marine science education and oceanographic research for more than 48 years. NSU's Guy Harvey Research Institute, provides the scientific information for the management and conservation of the world's marine fishes and their ecosystems.
More about Hammerhead shark, scalloped hammerhead shark, Endangered species
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