A warning sign about the danger of sharks is standing on the beach in the neighborhood of Boa Viagem, Recife, Pernambuco, Brazil, on January 27, 2024. (Photo by Emmanuele Contini/NurPhoto via Getty Images)
null - Sharks have tested positive for cocaine off Brazil’s coast, according to a new scientific study.
Scientists with the Oswaldo Cruz Foundation tested 13 Brazilian sharpnose sharks who all tested positive for the drug, and 12 out of the 13 also tested positive for benzoylecgonine, cocaine’s primary metabolite.
Their findings, published in the journal ScienceDirect, were the first on cocaine in free-ranging sharks, and the "findings point to the potential impacts of the presence of illicit drugs in environments," researchers said.
The scientists cautioned that studies "focusing on wild fish are, however, very limited."
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The highest concentrations of the drug were found in its muscle tissue, but some were also found in their livers with concentrations as much as 100 times higher than those found in other marine animals.
The researchers believe the sharks are ingesting cocaine from illegal drug labs in the area, according to BBC News.
It’s not clear how the presence of the drug in the sharks’ systems might affect the animals or the fetuses of the pregnant females who tested positive.
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Last year, scientists attempted to study the effects of cocaine in sharks off the coast of Florida.
"[Sharks have] gone up and touched it with the only thing they've got — their mouth — and taken a bite out of it. … So, it sounds crazy, but the probability of it occurring is actually quite high," marine biologist Tom "The Blowfish" Hird said of drugs that have been dropped by smugglers in the ocean.
During the research, Hird said sharks were "tuned up. They were on full alert, ready to go, looking, looking, looking." He said while the sharks did go into hunting mode, there was no increase in aggressive behavior.
As for how dangerous this could be for humans, Hird says the sharks are more of a danger to themselves than to people.
"If cocaine made sharks hyper and didn't put them to sleep, my personal belief would be that it would make them much more skittish. And the loud noises, things like divers in the water splashing, — all that kind of stuff — it's actually going to drive them away because it's going to act as a deterrent," he said.
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For the experiments, researchers didn't actually feed cocaine to sharks. Instead, they used highly concentrated fish powder to give sharks a similar high, as close to cocaine as ethically possible.
Fox News' Claudia Kelly-Bazan and Jonathan Serrie contributed to this report. Read more of this story from FOX News.