Sharks on Drugs in the Bahamas

Sharks in the Bahamas are consuming caffeine, painkillers, and even cocaine, according to a new study published in May in the online edition of Environmental Pollution. Scientists say it could potentially impact the animals' health and behavior.

The research team, made up of marine biologists and scientists from Brazil and other countries, analyzed blood samples from 85 sharks of five species. The sharks were captured about four miles off the coast of a remote island, and their blood levels were tested for 24 legal and illegal drugs. Twenty-eight of the sharks had detectable levels of caffeine, two common over-the-counter anti-inflammatory painkillers, or, in one instance, cocaine.

Medications, illicit drugs, and other substances are "increasingly recognized as contaminants of emerging concern" in oceans and other bodies of water, the researchers said. Areas that are "undergoing rapid urbanization and tourism-driven development" are especially at risk.

"While the detection of cocaine tends to draw immediate attention, the widespread presence of caffeine and pharmaceuticals in the blood of many analyzed sharks is equally alarming," said lead author Natascha Wosnick, a zoologist at Brazil's Federal University of Parana.

The sharks with contaminated blood had changes in metabolic markers, including those tied to stress and metabolism. The researchers said it's not clear if the changes are harmful, but it's possible they could lead to behavioral changes.

"Our primary concern is the potential implications for the health and stability of shark populations," Wosnick said. The data highlights "the urgent need to address marine pollution in ecosystems often perceived as pristine."

Tracy Fanara, a marine biologist who worked on a Discovery TV show called Cocaine Sharks that explored how sharks might be affected by the drug, told CBS News in 2023 about experiments that simulated cocaine exposure. She said it led to "strange behavior" that requires more research. During the show, she can be heard noting that a hammerhead shark appears to be pursuing a bale of fake cocaine.

In a separate study from 2024, scientists reported that sharks in the waters off Brazil tested positive for cocaine and benzoylecgonine, the primary molecule in cocaine. Those researchers looked at the levels of the substances in the sharks' liver and muscles. Each of the 13 sharks examined for the study tested positive for high levels of cocaine.

From a story by Kerry Breen, CBS News

P.S. But it's not just a problem for marine life in the Bahamas. The New York Times reports salmon in Sweden getting high on the illegal drug, and British newspapers, including the Independent, tell of high levels of Class A drug in London's River Thames, although they add that it does not appear to be harming its wildlife, although a study published last year found critically endangered eels could be made hyperactive. Eels deliberately exposed to cocaineinfused water by biologists at the University of Naples Federico II not only appeared hyperactive but also saw the drug accumulate in their brains, muscles, gills and skin.