Between 2021 and 2023, scientists working near Rio de Janeiro caught and dissected thirteen wild Brazilian sharpnose sharks and tested some of their muscle and liver tissue for cocaine. All tests were positive.
What could explain this?
If you guessed human cocaine use, you’re right. But the main source is probably not traffickers dumping containers of drugs in the ocean; it’s cocaine users. A biologist who worked on the study, Rachel Ann Hauser-Davis, thinks most of the cocaine is reaching them through wastewater: water polluted with human sewage, and (secondarily) runoff from illegal labs around Rio, that’s reaching the ocean and mixing with seawater.
Is cocaine good for sharks?
Probably not! Biologists think cocaine is likely affecting their brains and interfering with processes that support important survival skills–like migrating and giving birth.
Cocaine isn’t the only form of human pollution reaching sharks. Our wastewater can also expose them to legal pharmaceuticals, pesticides, fertilizers, and sunscreen.
Check out this cast, article, and documentary for more on what happens when cocaine and sharks meet. The research is still ongoing about how recreational drugs affect shark behavior!
And, should anyone need it, let this be one more reason to steer clear of cocaine!