Off the coast of Rio de Janeiro in Brazil, fishermen accidentally caught 13 Sharpnose sharks ― considered vulnerable to extinction ― between 2021 and 2023.
The 13 fish were dissected by scientists.
After examination, they found some troubling news ― all 13 of the sharks’ bodies contained both cocaine and benzoylecgonine, a metabolite produced by the body after breaking the drug down.
“While I’m not at all surprised to see cocaine metabolites in the water, as you’d expect that from human urine, I am surprised to see ‘cocaine’ in the water,” Tracy Fanara, an oceanographer at the University of Florida, told National Geographic.
Researchers know it comes from pollution, but it’s hard to know where exactly it comes from.
One source may be “its continuous environmental release from inadequate sewage treatment facilities [containing cocaine users’ urine],” the paper reads; another origin could be “clandestine refining operations” or “drifting cocaine packs not recovered by sellers or authorities.”
Of course, these are not mutually exclusive.
The scientists from the Oswaldo Cruz Foundation in Brazil add that global cocaine “consumption has increased exponentially” over the past couple of decades.
The sharks, which spend a lot of time near the shores of Brazil, may be especially likely to come into contact with pollutants due to their proximity to land.
Perhaps this is why concentrations of both cocaine and its corresponding metabolite are up to 100 times higher (woah) than previously recorded in other aquatic creatures.
On top of that, the paper revealed that though both cocaine and the main metabolite associated with it “have been detected in aquatic ecosystems,” they add that “Studies focusing on wild fish are... very limited.”
If you saw Cocaine Shark, a film in which marine biologist Tom Hird shared “We have no idea what [cocaine] could do to the shark,” well ― consider this a sequel.
Like Hird, scientists aren’t definite as to how cocaine affected the sharks. They didn’t notice any behaviour change. However, they do suspect it damaged their eyesight ― making it tougher for them to hunt.
“Moreover, environmental COC levels have been reported as toxic to various aquatic organisms,” they add.
The study, the researchers say, “highlights the urgency for robust legal frameworks and proactive measures to address this emerging environmental issue.”
