Scientists have found traces of cocaine in the blood of sharks swimming in the deep blue waters of the Bahamas for the first time.
The team came across the sharks under the influence while studying the marine animals around Eleuthera Island, located 50 miles east of Nassauin the Atlantic Ocean.
They also found caffeine and painkillers in blood samples taken from three different species of shark.
The sharks did not behave unusually, nor were they intoxicated.
However, the presence of these drugs adds to increasing evidence that substances intended only for human consumption are making their way into wild ecosystems.
It remains unclear how the sharks were able to get hold of the drugs.
However, the researchers from the Cape Eleuthera Institute in the Bahamas suspect that packets of cocaine may have fallen into the water.
‘They bite things to investigate and end up exposed to substances’, lead author Natascha Wosnick told Science News.
Scientists have found traces of cocaine in the blood of sharks swimming in the deep blue waters of the Bahamas for the first time
The sharks did not behave unusually, nor were they intoxicated. However, the presence of these drugs adds to increasing evidence that substances intended only for human consumption are making their way into wild ecosystems (stock image)
Of the 85 animals tested, caffeine was the most frequently detected substance, with 27 sharks testing positive.
Cocaine was found in two of them, while diclofenac, a common anti-inflammatory, was seen in 13 and paracetamol was detected in four animals.
The study found the highest number of detections came from one site popular with tourists.
The researchers also found changes in metabolic markers in sharks with contaminated blood, including lactate and urea.
Worryingly, it remains unclear whether these changes are harmful, or how they might impact the sharks’ behaviour.
Speaking to Science News, Tracy Fanara, an oceanographer at the University of Florida in Gainesville, who was not involved with the study, said: ‘What makes this study notable is not just the detection of pharmaceuticals and cocaine in nearshore sharks, but the associated shifts in metabolic markers.’
This is the first time caffeine and paracetamol had been recorded in sharks anywhere in the world.
It’s also the first time cocaine and diclofenac have been found in sharks in the Bahamas.
The team came across the sharks under the influence while studying the marine animals around Eleuthera Island, located 50 miles east of Nassauin the Atlantic Ocean
Though the paper, published in the journal Environmental Pollution, did not identify a specific source of contamination, researchers believe that increased tourism in the area leads to more vessels in sharks’ habitats.
This, in turn, leads to more wastewater and more chemical residues being found in sensitive ecosystems.
The news comes shortly after sharks swimming in the waters around the coast of Brazil tested positive for cocaine.
Scientists carrying out a study for the Oswaldo Cruz Foundation tested 13 of the Brazilian sharpnose type shark taken from South Atlantic Ocean near Rio de Janeiro.
They found they all had high levels of the drug in their muscle and liver.
Dr Rachel Ann Hauser-Davis, a British scientist and member of the research team from the Oswaldo Cruz Foundation, said this was ‘due to human use of cocaine in Rio de Janeiro and the discharge of human urine and faeces by sewage outfalls, as well as from illegal labs’.
