Drugs in the water: Sharks near Eleuthera test positive for cocaine and pharmaceuticals

Sharks swimming off the coast of Eleuthera, often seen as one of the country’s most pristine marine environments, are showing signs of exposure to human drugs, raising new concerns about pollution in Bahamian waters.

What happened

A recent study published in Environmental Pollution found that sharks in Bahamian waters had traces of substances including caffeine, painkillers and even cocaine in their blood.

The research, led by biologist Natascha Wosnick of the Federal University of Paraná, analyzed blood samples from 85 sharks captured around Eleuthera.

Twenty-eight sharks — including nurse sharks and Caribbean reef sharks, tested positive for at least one drug. Some showed multiple substances.

What it means

Unlike previous studies that tested muscle tissue, this research examined blood, meaning the exposure is likely recent and ongoing.

Scientists say this points to a troubling reality: even in areas considered remote or untouched, human activity is directly affecting marine life.

What scientists are saying

Wosnick believes the contamination is likely linked to human presence.

“It’s mostly because people are going there, peeing in the water and dumping their sewage,” she said, noting that currents can also carry pollutants offshore.

Oceanographer Tracy Fanara, who was not involved in the study, said the findings highlight how tourism, infrastructure and marine ecosystems are deeply connected.

The numbers

• 85 sharks tested
• 28 showed drug contamination
• Substances detected: caffeine, acetaminophen, diclofenac
• One shark tested positive for cocaine

Most sharks were caught about four miles offshore, near a former fish farm popular with divers.

What’s unknown

Scientists say it is still unclear how these substances affect sharks long-term.

However, early signs including changes in metabolic markers, suggest possible impacts on stress levels, energy and behavior.

What’s at stake

The Bahamas’ global reputation as a marine paradise and a hub for eco-tourism could be at risk if pollution continues to go unchecked.

Marine ecosystems are not just environmental assets; they are economic lifelines.

The state of play

While public concern often focuses on plastic pollution or oil spills, experts warn that chemical pollution may be just as widespread and far less visible.

The findings serve as a reminder that even in the Bahamas, environmental threats are evolving and may already be closer than many realize.