Sharks in the Bahamas have tested positive for cocaine and other drugs. The increased tourism and urbanization has led to the contamination of saltwater climates, which in turn affects our animals. 

Scientists caught 86 different sharks, spanning multiple species. They took blood samples from these sharks and tested them for 20 different kinds of substances. Around one third of the sharks tested positive for illicit substances. 

These tests were run on sharks around Eleuthera Island, which is a rather secluded island compared to the rest of them. This raises even more concern due to the lack of tourism and human contact with these sharks and yet they still have alarming numbers of substances in their blood stream.

Substances that showed on blood tests include: caffeine, diclofenac, acetaminophen, and cocaine. Both diclofenac and acetaminophen are in over the counter painkillers. Caffeine was the most common positive, with 12 sharks testing positive ranging from 2.68 to 29.70 ng mL−1 . This measurement is nanograms of caffeine to one ounce of blood. 

There were 28 sharks across multiple species (nurse shark, Caribbean reef sharks, and lemon sharks), which had detectable levels of caffeine, cocaine, or painkillers. Although detectable levels are not always high levels, the fact that there is any level of drugs in sharks blood systems is indicative of the pollution and harm we have done to our ecosystems. 

Many people see the word ‘cocaine’ and it draws their attention. The fact that there is any level of cocaine in sharks is disturbing, but this draws attention away from the other results. There is a significantly larger quantity of caffeine and painkillers found in sharks bloodstream throughout the waters surrounding Eleuthera Island. 

“While the detection of cocaine—an illicit substance—tends to draw immediate attention, the widespread presence of caffeine and pharmaceuticals in the blood of many analyzed sharks is equally alarming,” said Natascha Wosnick, the co-author of a published study. Caffeine and different painkillers have seen a much higher percentage in their blood.

There is increased worry around the levels of caffeine and painkillers because of how easily accessible these substances are. The reason there are higher levels of these substances is because of how common they are in stores and households. Caffeine is the widest used drug around the world and painkillers can be found in any grocery or drug store. 

This calls into question how we should handle our everyday habits. Despite the normalization of caffeine and painkillers in everyday life, they still pose a problem to our natural ecosystems. 

There have been previous studies done on the presence of substances in marine mammals before. These studies focused on invertebrates and bony fish, leaving sharks mostly unstudied. This study focuses entirely on sharks, and was published in the May 2026 article of Science Direct. 

The way the sharks are getting access to these substances is through the water and the reason sharks closer to the urbanized areas have higher concentration of substances is because of pollution and contamination. Continuous contact with humans leads to pollution. Sewage drains off into the water, so anything that is flushed, whether it be drugs themselves or waste from somebody who has consumed those drugs, it goes into our waterways. 

Sharks also absorb things through their gills, which is essentially how they breathe, the same goes for all fish. They absorb chemicals and drugs through the water, which gets into their bloodstream. 

“Cocaine Sharks” (2023) is a documentary that followed research in Florida which sought to understand the reaction of stimulants in sharks. They found that when exposed to large quantities of stimulants, the sharks would go after the drugs instead of food. This research was prompted by the increasing amounts of cocaine being brought into the United States that would wash up on Florida beaches. 

The researches have seen alterations in tissues within the sharks due to the drugs. This can lead to long term effects. The biological markers of change in these animals has increased worries of the eventual shark population especially in the Bahamas area. 

Scientists are currently worried about behavioral changes. They are not worried about increased aggression, but the health of the sharks going forward. Seen in the research done in “Cocaine Sharks” implies that sharks could start starving themselves by seeking out substances rather than food. 

This discovery has been alarming to many as the Bahamas has been actively trying to protect shark populations. In 2011 the Bahamas created the first shark sanctuary in the Atlantic Ocean. These waters are home to over 40 different species of sharks through their 430,000 km² marine areas. 

Their beautiful waters and commitment to the protection of marine life makes them a popular destination for tourism, including shark diving and snorkeling. Their marine habitat also has many other protected marine species including the Caribbean Queen Conch and the Nassau Grouper fisheries. These provide over $63 million annually to the islands through tourism. 

Shark tourism alone provides almost $100 million annually. This is currently being threatened by illegal fishing, which not only harms sharks directly, but harms their habitat and food population. Tourism and illegal fishing also threatens the health of the waters themselves with pollution and damage to their ecosystem. 

The effects of this are still poorly understood. We have no long term data on the effects of drugs in sharks blood, making the future unpredictable. This could decimate the future shark population or cause irreparable harm to their long term biological effects and design.

Although we do not fully understand what this means, we should still clean up our oceans and work to prevent pollution in the waters and pull back on tourist and human exposure to these animals.