SHARKS in Brazil have tested positive for cocaine and scientists say they have multiple theories as to how the class A drug reached the South Atlantic Ocean.
Scientists tested 13 Brazilian sharpnose sharks found along the Rio de Janeiro coast and found high levels of cocaine in their bodies.
The Oswaldo Cruz Foundation, who carried out the research, say the drug heavily lined the sharks’ livers and muscles.
The paper, published in Science of the Total Environment, suggests that the drug filtered through pipes of drug labs, into the South Atlantic Ocean.
Other possibilities of exposure include drug users’ excrement that has made its way into the ocean through untreated sewage.
Researchers also considered the idea that narco smugglers had dumped the dangerous drug into the seas, leading to the sharks gnawing on it but think this is less likely.
Brit Dr Rachel Ann Hauser-Davis, a member of the research team, told The Telegraph: “[Results showed] chronic exposure due to human use of cocaine in Rio de Janeiro.”
She suggested that chronic exposure could also be explained by “the discharge of human urine and faeces by sewage outfalls, as well as from illegal labs.”
She acknowledged that there is not any proof that the drug makes the fish more aggressive or likely to go on a feeding frenzy.
However, she says it’s likely that the drug is harmful for them to ingest.
Her team worry that the sharks’ ingestion of cocaine could damage their eyes, harm their hunting skills and reduce their life expectancy.
Dr Tracy Fanara from the University of Florida, who was not involved in the study, told The Telegraph that she suspects cocaine in the sharks’ systems could affect fertility.
She said: “They may not be going nuts from the cocaine but it could reduce their life expectancy.”
Dr Enrico Mendes Saggioro, from the research centre, told the newspaper that other animals showed erratic behaviour after consuming cocaine and didn’t rule this out for sharks.
But he also stressed that more studies would be needed to prove the drug’s impact on sharks.
The Brazilian sharpnose sharks used in the study were taken off small fishing boasts that travelled the coastal waters off Rio de Janeiro.
Researchers dissected them before examining them and discovered concentrations of cocaine up to 100 times higher than previously found in similar animals.
The New York Post reported that sharks in the Florida Keys were getting high on cocaine after drug traffickers dumped the white powder into the water.
Last year, marine biologist Tom Hird investigated the link between sharks and cocaine consumption on TV series “Cocaine Shark”.
He headed underwater and noticed some sharks acting strangely.
Testing the sharks’ inclination for the drug, he hurled packets of bales filled with fish powder on the Discovery TV show.
To his amazement, multiple “super feisty” sharks munched on the feed and even ignored the decoy swans he chucked in to the sea.
He concluded that the sharks would rather feast on a foreign object than what they perceived to be a living creature, a swan.
He told the Post: “I firmly believe, and it’s not just a chance of probability, that a shark will come across a floating bale [of cocaine] and take a bite.”
He continued: “What’s interesting is that the sharks we saw…weren’t right, they weren’t just so, they seemed a little bit off — now that was very interesting.”
The scientist explained that while limited research had been done on shark’s reaction to cocaine, there was nothing to suggest the hyperactivity was not related to the drug.
COCAINE snorted by Londoners is polluting the Thames — and making eels hyperactive. There are even fears the critically endangered fish could become too confused to migrate the 3,000 miles across the Atlantic to breed.
Cocaine enters the river in users’ urine via treated sewage. Untreated sewage can also get in following storms.
Researchers at King’s College monitored levels near the Houses of Parliament and found consistently high amounts.
In many other cities, cocaine use peaks at weekends.
The experts said: “London is known as one of the highest consumers of cocaine and this suggested every day usage.”
They want water treatment systems improved but noted the giant Tideway Tunnel sewer should stop any waste entering the river when it opens in 2023.
The London team detected cocaine levels in the river at more than one microgram per litre of untreated wastewater.
Scientists in Italy have found 0.02mg of cocaine per litre is enough to send eels in tanks into a frenzy, and causes damage to their muscles.
