Thirteen sharks living off the coast of Brazil recently tested positive for cocaine, marking the first time that cocaine has been found in free-range sharks.
A paper by researchers with the Oswaldo Cruz Foundation in Brazil that was obtained by CNN noted that scientists discovered cocaine in both the liver and muscle tissue of 13 Brazilian sharpnose sharks found in the waters surrounding Rio de Janeiro.
According to the new study, the Brazilian sharpnose shark species was selected due to the size and location of the sharks. The sharks live in coastal waters that are exposed to a significant amount of contamination.
The study found that cocaine levels were roughly three times higher in the sharks’ muscle tissue than in the liver tissue. The study also found that female sharks had a higher concentration of cocaine in the muscle tissue.
According to Sky News, the study showed that the cocaine concentration levels in the 13 sharks were up to 100 times higher than other levels previously studied in ocean animals.
Enrico Mendes Saggioro, an ecotoxicologist and co-author of the study, told CNN that cocaine pollutes the sea through sewage discharges from people who use cocaine and from illegal cocaine laboratories. The study noted that cocaine consumption has increased globally over the past few decades.
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Researchers shared that approximately 22% of cocaine users are located in South America and that Brazil is the second-largest cocaine consumer market in South America. The researchers reported that the increased consumption of cocaine and poor infrastructure for sewage treatment has led to increased cocaine levels in the ocean.
While previous research indicated that cocaine dumped into the sea by illegal traffickers could contribute to contamination levels, Mendes Saggioro told CNN, “We don’t usually see many bales of coke dumped or lost at sea here, unlike what is reported in Mexico and Florida.”
While studies have not been completed to determine how cocaine might damage the health of the sharks, Mendes Saggioro and co-author Rachel Ann Hauser Davis noted that other research points to the damage cocaine causes to fish and mussels.
“It is probable, although not yet proven that exposure would have deleterious physiological effects on the sharks,” the co-authors stated.
