Scientist Finds 'Genetically Distinct' Shark

Jun 08, 2006
Scientist Finds 'Genetically Distinct' Shark
"Cryptic species" of hammerhead shark, discovered by USC biologist Joe Quattro and collaborators, unique to South Carolina coast.

Biology professor Dr. Joe Quattro, collaborating with Dr. Jim Grady at the University of New Orleans and Dr. Trey Driggers with the National Marine Fisheries Service, has discovered a genetically distinct species of the hammerhead shark. Classified under the genus, sphyrna, the species is the ninth recognized in the hammerhead family and will be called the "cryptic species" until a formal description is pronounced.

Because the species appears to be rare and localized to the South Carolina coast, it is at high risk for extinction and makes the state's coastal waters crucial for conservation efforts. Many shark species in the northwestern Atlantic have declined in recent years.

According to the Florida Museum of Natural History Web site, hammerheads are considered potentially dangerous sharks. The International Shark Attack File documents 21 unprovoked attacks with 2 resulting fatalities for all species of the genus Sphyrna. Scalloped hammerheads have been reported to display threatening postures when closely approached by divers on some occasions while other times they show no aggressive behaviors.

Quattro discovered the species while studying coastal fish with biologists from the S.C. Department of Natural Resources. He developed an interest in hammerhead sharks and noticed that something strange was occurring in the genetic makeup of some. He and his colleagues found that the genes in the mitochondrial DNA -- the DNA passed from mother to sons and daughters -- differed significantly among sharks that, by all other measures, were scalloped hammerhead sharks. Moreover, his studies revealed that another independent genetic marker also differed substantially between the two groups of scalloped hammerheads.

"This cryptic shark was genetically distinct," said Quattro, whose research on the cryptic hammerhead sharks was published recently in the journal, Marine Biology.

Quattro and his colleagues also found that the cryptic species was not as abundant as the scalloped hammerhead, which is a familiar and common coastal shark. Although young sharks of the cryptic species were found in Florida and North Carolina, only neonates -- or shark "pups" -- were showing up off the coast of South Carolina, particularly in the area of Bull's Bay near Beaufort and St. Helena's Sound.

"The apparent abundance of the cryptic species in coastal South Carolina could be a result of sampling, but it might also highlight the fact that the South Carolina bays are the more important nursery grounds for the cryptic species," Quattro said.

Although scientists don't know why the cryptic sharks appear to prefer South Carolina waters, Quattro speculates that something as simple as salinity differences in the waters may be a factor.

"Protecting this prime nursery habitat is vital to the survival of the cryptic species," said Quattro, who plans to head to the Atlantic this summer for a project to tag the cryptic sharks. The tags will enable the researchers to learn where the sharks go after leaving South Carolina's waters.

Because the cryptic shark appears to have a narrow geographic distribution, it is at a greater risk for extinction, he said, and conservation efforts are needed to protect females during their reproductive season.

"If South Carolina's waters are the primary nursery grounds for the cryptic species and females gather here to reproduce, these areas should be conservation priorities," Quattro said. "Management plans are needed to ensure that these sharks are not adversely impacted so that we can learn more."

Source: University of South Carolina

Explore further: Endangered clouded leopard kittens born in Miami zoo

Related Stories

It's survival of the most useful when protecting species

Jan 12, 2015

Consensus is growing that we are steering towards a sixth mass extinction event. There are calls for increased efforts to stop the accelerating loss of plants and animals. But do we really need to protect ...

Researchers unveil rich world of fish biofluorescence

Jan 08, 2014

A team of researchers led by scientists from the American Museum of Natural History has released the first report of widespread biofluorescence in the tree of life of fishes, identifying more than 180 species ...

The Carolina hammerhead, a new species of shark, debuts

Nov 07, 2013

Discovering a new species is, among biologists, akin to hitting a grand slam, and University of South Carolina ichthyologist Joe Quattro led a team that recently cleared the bases. In the journal Zootaxa, they d ...

Recommended for you

Deciphering the origins of cell behavior

1 hour ago

Researchers at the Mechanobiology Institute, National University of Singapore, have made significant advances in our understanding of cellular biology; providing evidence that the inherent 'handedness' of ...

Rare south-west fish suffers further decline

3 hours ago

Researchers have discovered that the range of one of Western Australia's rarest freshwater fishes, Balston's Pygmy Perch, could have declined by as much as 25 per cent.

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.