New Hammerhead Shark Confuses Conservationists

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There's good and bad shark news. The good news is that a new, as of yet unnamed, species has been discovered. The bad news is that it looks just like the scalloped hammerhead shark, curtailing efforts to save that endangered species.

The new look-alike hammerhead is identical to its near twin save for a few important differences:

  • distinctive DNA
  • 20 fewer vertebrae (about 170 versus 190)
  • a genetic profile suggesting it separated from the scalloped hammerhead 4.5 million years ago

That's an incredibly long period of time, considering how similar the two different sharks look externally.

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Adding to the confusion is that the new mysterious species seems to have a large range. It was originally discovered off the eastern U.S. Now a paper in the April issue of Marine Biology mentions it's been found more than 4,300 miles away near the coast of southern Brazil.

The look-alike species may face the same fishery pressures as the real scalloped hammerhead, which is being fished unsustainably for its highly prized fins.

“It’s a classic case of long-standing species misidentification that not only casts further uncertainty on the status of the real scalloped hammerhead but also raises concerns about the population status of this new species,” Mahmood Shivji said in a press release.

He oversaw the new research at the Nova Southeastern University Oceanographic Center's Save Our Seas Shark Center and Guy Harvey Research Institute.

“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,” he added. “Without management intervention to curtail its inadvertent killing, we run the risk that overfishing could eradicate an entire shark species before its existence is even properly acknowledged.”

At least 7 percent of the sharks in U.S. waters originally thought to have been scalloped hammerheads now turn out to be the new species. This means that the population of the endangered real scalloped hammerhead in American waters is probably smaller than originally thought.

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This latest discovery about the twin species could (and should, in my opinion) influence how the U.S. National Marine Fisheris Service classifies the scalloped hammerhead (Sphyrna lewini). Depending on what's decided, this shark could be listed as threatened or endangered. The species is already on the IUCN Red List of Endangered Species.

The new "twin" shark may also be endangered, but it's not officially protected yet.

Shivji concluded, “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."

Keep in mind that we are part of this food chain too, with our bad decisions coming back to bite us. Human overfishing of scalloped hammerheads has caused the cownose ray population to rise. The rays, in turn, are eating more of their fave food, bay scallops. These are the same scallops that many humans like to eat, so the supply of scallops for us is now in jeopardy.

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