What Scientists Found in Bahamian Sharks Is Alarming

Sharks cruising off a far-flung Bahamian island are turning up with something unexpected in their blood: traces of caffeine, painkillers, and, in one case, cocaine. In a new study cited by CBS News, researchers tested blood from 85 sharks representing five species for two dozen legal and illegal drugs. Of those subjects, 28 had detectable levels of substances, including common anti-inflammatory medications and caffeine, with some sharks carrying more than one compound. Lead author Natascha Wosnick of Brazil's Federal University of Parana says the focus shouldn't be on the more-sensational drug names alone: Everyday substances like coffee and over-the-counter meds are leaving a measurable mark in waters once considered pristine.

In cases involving cocaine, researchers believe sharks may have bitten through packets that somehow ended up in the water, per ScienceAlert. "They bite things to investigate and end up exposed," says Wosnick. Contaminated sharks showed shifts in metabolic markers related to stress and energy use, though scientists don't yet know if the changes are harmful or how they might alter behavior. The study adds to mounting evidence, including from earlier Brazilian research that found high cocaine levels in sharks' tissues, that human pharmaceuticals and illicit drugs are now part of the marine environment, prompting calls for tougher action on ocean pollution, especially in rapidly developing coastal tourist zones.