Multiple sharks captured off the coast of Brazil have tested positive for cocaine, according to a new study in Science of the Total Environment.
The study found that 13 sharpnose sharks, which were accidentally captured by fisherman and examined between 2021 and 2023 off the coast of Rio de Janeiro, had cocaine in their systems. All of the sharks examined during this period were found to have cocaine in their muscles and liver.
Cocaine levels were found to be 100 times greater than is typical for marine animals.
The study was launched after co-author Enrico Mendes Saggioro detected cocaine while examining river pollutants in Rio de Janeiro.
Investigators are not certain what caused the cocaine to be found in the water. It is possible that some of the cocaine reaches the sea due to the activity of illegal drug manufacturing laboratories, or the excretions of drug users.
No studies have been carried out to determine if cocaine affects the behavior or health of sharks.