Sharks in Brazilian waters are showing alarmingly high levels of cocaine contamination, scientists report.
A study found that 13 sharpnose sharks captured in the region had cocaine concentrations in their muscles and livers up to 100 times higher than previously recorded.
These findings suggest that the sharks are being exposed to the drug through pollution, although the exact pathway remains unclear. One theory is that the cocaine enters the ocean via wastewater, as human urine and feces containing drug residues are discharged into the sea. Another possibility is contamination from illegal drug labs, which might release cocaine into waterways.
The study, published in the journal Science of the Total Environment, highlights the presence of both cocaine and its main metabolite, benzoylecgonine, in the bodies of these sharks.
Researchers specifically chose Brazilian sharpnose sharks for the study because they inhabit coastal waters, making them more susceptible to pollution.
The phenomenon of “cocaine sharks” has captured public interest, inspiring a Discovery TV program exploring how sharks might ingest drugs from bales lost or dumped by smugglers, although such occurrences are rarer in Brazil compared to areas like Mexico or Florida.
Real-life exposure to cocaine could have adverse effects on sharks, according to researchers. High levels of the drug might impair their vision, hindering their ability to hunt.
Dr. Tracy Fanara, an ecotoxicity expert at the University of Florida, suggested that the drug could also impact shark reproduction and growth rates.
Furthermore, cocaine exposure could potentially alter shark behaviour, leading to increased aggression or feeding frenzies, although further research is needed to confirm these effects.
[Image created via MidJourney]