KUALA LUMPUR: Sharpnose sharks in Brazil have tested positive for cocaine, a new study has found.
The study, published in Science of the Total Environment, discovered traces of this drug in the sharks' livers and muscles. This research marks the first instance of cocaine being identified in sharks, with concentrations reported to be up to 100 times higher than previously found in other aquatic animals.
Researchers examined 13 sharks off the coast of Brazil and found cocaine in all of them. Additionally, they detected benzoylecgonine, the primary metabolite of cocaine, in 12 of the sharks.
The scientists, who conducted the study titled "Cocaine Sharks," dissected 13 sharpnose sharks captured near a beach in Rio de Janeiro. All of the female sharks in the study were pregnant, though the effects of cocaine exposure on their foetuses remain unknown.
It is also uncertain whether cocaine affects shark behaviour.
According to study coordinator Enrico Mendes Saggioro, the study results show cocaine is being widely traded and moved in Brazil, regardless of where the drug came from, which he added is still not possible to determine.
"Cocaine has a low half-life in the environment. So, for us to find it in an animal like this, it means a lot of drugs are entering the biota," The Guardian quoted him as saying.
In other studies, Saggioro had previously found cocaine in rivers flowing into the sea off Rio de Janeiro, but he was surprised to discover it in sharks– and at such high levels. Brazil is one of several countries where cocaine has been detected in sewage and rivers.
It is believed that the drug might have entered the sea around Rio de Janeiro from the drainage of illegal drug labs or from cocaine packages that were dumped or lost.
Another concern raised by the study is that shark meat is a common food source in Brazil, meaning contaminated sharks could pose health risks.
Brazilian sharpnose sharks inhabit the tropical waters of the western Atlantic and typically grow to less than 91 centimetres in length.