Thirteen Brazilian sharpnose sharks caught off the coast of Rio de Janeiro have tested positive for cocaine, according to marine biologists from the Oswaldo Cruz Foundation in Rio de Janeiro.
This previously reported news story has sparked renewed interest and gained momentum in the past week, rekindling concerns for both sharks and the environment.
Researchers discovered high concentrations of cocaine in the muscles and livers of these sharks. Additionally, benzoylecgonine, a byproduct of cocaine metabolism, was detected in the same sharks. Among the thirteen sharks tested, three were males, and ten were females, five of which were pregnant. These sharks were captured from fishing boats off the coast of Rio de Janeiro between September 2021 and August of the previous year.
Samples taken from the sharks revealed that the concentration of cocaine was over 100 times higher than previously reported in any other aquatic animals. The study suggests this is largely due to increased cocaine usage in the region along with inadequate drainage systems, leading to higher quantities of cocaine being present in seawater.
The study also noted that sewage analysis covering 60 million people in 37 countries from 2011 to 2017 consistently revealed the presence of cocaine in aquatic environments.
Narcotraffickers, when pursued in international waters, often discard bales of cocaine overboard. However, researcher, Hauser Davis suggests that the sharks in the study were more likely exposed to Rio de Janeiro's wastewater contaminated with the drug. “Probably the main source would be human use of cocaine and its metabolisation, followed by urine and faeces discharge. The second source would be from illegal refining labs,” she says.
Hauser Davis also notes that cocaine affects the brain and could lead to hyperactive behaviour among sharks, though she emphasises that further research is needed on this issue.
The presence of cocaine in marine life highlights significant pollution and its potential harmful effects on aquatic ecosystems. These harmful effects include potential behavioural changes in sharks, such as hyperactivity, and broader ecological disruptions. Additionally, the contamination of marine environments with drugs like cocaine indicates severe pollution, which can harm various aquatic species and disrupt the delicate balance of marine ecosystems. For example, a 2018 study in the United Kingdom found that eels exposed to cocaine faced challenges with reproduction.
The growing evidence of drug pollution's impact on aquatic ecosystems underscores the urgent need for improved waste management and protection of marine environments.
If you'd like to support Shark Guardian in their mission to save and research sharks, you can contribute in several ways: make a donation, shop for merchandise, or become a Shark Guardian member today!
Comments