"The key findings of the study are the presence of cocaine in sharks. The actual high levels of cocaine detected in muscle is indicative of chronic exposure." Narcotraffickers being chased in the high seas often toss bales of cocaine overboard. But Davis says it's more likely the sharks in the study were exposed to Rio de Janeiro wastewater contaminated with the drug.
“Probably the main source would be human use of cocaine and metabolization and urine and feces discharge, and the second source would be from illegal refining labs.”
Not only are they hyperactive, but it's possible their sex lives are at risk!
Davis points out that cocaine impacts the brain and could lead to hyperactive behavior among sharks – though she says the issue needs more research.
The findings in Brazil adds to a growing body of research on marine wildlife and cocaine. For example, a 2018 study in the U.K. found that eels exposed to cocaine were having trouble mating.