Off the coast of Brazil, scientists have for the first time detected cocaine residues in sharks. A total of 13 Brazilian sharpnose sharks (Rhizoprionodon lalandii), caught near Rio de Janeiro, were examined. The analyses revealed alarmingly high concentrations of the drug in the animals’ muscles and livers – in some cases up to 100 times higher than ever measured before in other marine animals.
How does cocaine enter the sea?
The research, conducted by the renowned Oswaldo Cruz Foundation, suggests that cocaine enters the oceans through various pathways. On the one hand, via illegal laboratories where the drug is produced, and on the other, through human excretions after consumption. Less likely, but not impossible, is the possibility that smugglers throw or lose cocaine packages in the sea.
“The results are very important and potentially worrying,” explained Sara Novais, marine ecotoxicologist at the University of Leiria, to the journal. Science.
⚠️RIO NÃO É PARA AMADORES! Pela primeira vez na história, uma pesquisa analisou 13 tubarões da espécie bico-fino e em todos eles foram encontrados resquícios de cocaína nos músculos e fígado dos animais.
— BAÚ DO RIO OFC (@baudorio) July 24, 2024
Os tubarões foram retirados do mar no Recreio dos Bandeirantes. pic.twitter.com/mL7jZTnSfX
Unknown consequences for sharks and their offspring
Another striking finding: all the female sharks examined were pregnant. The effects of cocaine on the unborn pups are still completely unknown. Researchers point out that substances like cocaine could have similar effects on animals as on humans – which could have far-reaching consequences for the shark population.
The scientists emphasize that further studies are urgently needed to understand possible behavioral changes in sharks as well as long-term damage to the marine ecosystem. Previous research in other regions had already shown that chemical residues of drugs in the sea are not uncommon. For example, traces of benzoylecgonine, a breakdown product of cocaine, were found in seawater off the south coast of England last year.
The discovery off Rio highlights how illegal drug flows affect not only societies but also nature and its sensitive ecosystems.
