Researchers Locate ‘Missing’ Sharks With DNA From Ocean
“CSI Miami,” say hello to Animal Planet. Researchers from FIU were part of a team that successfully used ocean water to find missing sharks.
MIAMI, FL — “CSI Miami,” say hello to Animal Planet. Researchers from Florida International University were part of a team that successfully used ocean water to confirm the presence of certain species of sharks that had not been seen in some time. The “missing sharks” were found in the Pacific Ocean through traces of DNA left behind in the ocean water after the sharks swam through.
“Oh yeah. I think it really sounds like forensics,” FIU marine researcher Jeremy Kiszka said in an interview with Patch. “It’s not very different actually from DNA forensics as we see it on ‘CSI Miami.'”
The findings were published Thursday in the scientific journal, Science Advances.
Scientists had feared that some species of sharks had completely disappeared from areas where they were once common. FIU partnered with an international team of researchers to retrieve fragments of DNA from shark skin, excretions and blood in the water to find the sharks.
“It’s really interesting because now it gives us the opportunity to see this dark diversity that we are talking about in the paper, the species that are so rare, but also for some of them — so elusive,” explained Kiszka.
The team detected the presence of more shark species in just 22 samples of seawater filtered for DNA fragments than 3,000 dives and 400 baited videos in New Caledonia, a French South Pacific territory. The results were consistent in remote areas along pristine coral reefs and near more impacted areas where sharks are scarce, according to researchers.
“We have all been surprised by these results,” added Kiszka, a co-author of the study. “It’s exciting to know how useful this tool is, particularly to monitor the presence of rarer and more elusive species, which potentially includes endangered species.”
He said that researchers hope to expand the use of the DNA to find critical habitats for other endangered marine species.
Nearly half of all species of sharks, rays, and chimeras are data-deficient in the International Union for Conservation of Nature’s Red List of Threatened Species, a comprehensive source of the global conservation status of plants and animals, researchers explained.
That means more information is needed from scientists to determine a protection status for these rare and elusive species.
Other researchers in the study were from France, the United Kingdom, and Australia. They believe that by acquiring a small number of additional samples, they will be able to determine which shark species are really missing in the region and which have a chance to rebuild their populations and thrive again.
“We just used methods that were developed by others before,” Kiszka said. “The way we did it is a little bit different.”
He said that the DNA turned up about 13 different species as compared to only 9 found by divers and 9 by underwater cameras.
“We now see species for which we didn’t have any information,” he added.
But the technology also raises questions for which scientists don’t have answers at present.
“We have to better understand what are the limits of the methods,” he explained. “How long do they persist? How do ocean currents affect findings? There are still many things that we need to do, but what we found is really encouraging.”
He said that the great hammerhead shark, for example, is one species that has declined by about 90 to 95 percent as a result of commercial fishing.
“It’s important to know the areas where these rare and endangered species are,” he said. “It’s sort of a CSI investigation.”
Photo courtesy FIU