Are there sharks in the water? New DNA test might let humans sniff them out

New research from the University of California Santa Barbara could allow the public to know if there are great white sharks nearby — something sure to be a boon to lifeguards, researchers and anyone who’s ever nervously scanned the ocean shore.

Researchers there have uncovered a way to track great white shark DNA in the water, giving at “a rough idea about where sharks actually are at a particular moment,” according to a university statement.

“One of the goals of this research is for a lifeguard to be able to walk down to the shore, scoop up some water, shake it and see if white sharks are around,” Kevin Lafferty said in a statement.

Lafferty, a U.S. Geological Survey ecologist and researcher with UCSB’s Marine Science Institute, was lead author of the paper announcing the shark-tracking findings, published in Frontiers in Marine Science.

Co-author Chris Lowe, a professor at California State University Long Beach, found that while great white populations have begun to recover from overfishing thanks to state and federal regulations, “white shark recovery has co-occurred during a period when more people than ever before are using the coastal ocean for recreation, ultimately increasing the likelihood of interactions.”

That rise in population hasn’t correlated in more shark attacks, Lowe said. Great white sharks don’t view humans as food, but on rare occasions will bite a human “out of defensiveness, curiosity or mistaken identity, causing grave or lethal injuries,” according to a university statement.

But while rare, shark DNA tracking could be a valuable tool for lifeguards to prevent shark attacks.

It works by tracking shark mucus, feces or shed skin, all of which carry the shark’s DNA, “which can be parsed out and identified through genetic sequencing,” according to the university.

Work began on studying such “environmental DNA” 10 years ago, researcher Chris Jerde said.

“The advances in technology since then have dramatically improved the reliability, portability and widespread application of the method,” Jerde said in the university statement.

It’s imperfect -- that DNA can drift in the currents and sharks are capable of moving large distances in that tiime -- but it could still “give lifeguards and other people responsible for public safety clues as to when to be extra vigilant, and also help marine biologists understand how well white sharks are recovering in response to protection,” according to a university statement.

The technology isn’t limited to tracking great whites.

“New advances in (environmental DNA) are allowing for not just a single species to be detected, but instead the DNA for the water sample is screened for all fish species or all amphibian species,” Jerde said in the statement.

That includes tracking invasive species or endangered species.

Andrew Sheeler: 805-781-7934, @andrewsheeler

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