Sharks in the Bahamas are ingesting drugs—including cocaine, caffeine and painkillers—according to a study published in February in the journal Environmental Pollution. Scientists identified blood contamination in about one-third of tested animals, findings that highlight how humans are harming marine environments.
Researchers captured 85 sharks representing five species near Eleuthera Island in the Bahamas. The team collected blood samples from the animals and then released them. They examined the specimens for about 20 different drugs, spanning classes including antibiotics, antidepressants and opioids. Analyses revealed that 28 sharks across three species—Caribbean reef sharks, nurse sharks and lemon sharks—had detectable levels of at least one of four drugs: cocaine, caffeine and the painkillers diclofenac and acetaminophen.
Widespread Pharmaceutical Contamination
According to study co-author Natascha Wosnick, a biologist with the Federal University of Paraná in Brazil, the widespread presence of caffeine and pharmaceuticals in shark blood is particularly concerning. “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. These are legal substances, routinely consumed and often overlooked, yet their environmental footprint is clearly detectable.”
Biological and Behavioral Implications
The data showed that sharks with contaminated blood had changes in some biological markers, which can point to how tissues are functioning. Though researchers don’t know if the alterations are detrimental, the team suggests they could lead to behavioral changes. Wosnick stated that the primary concern is “not an increase in aggression toward humans, but rather the potential implications for the health and stability of shark populations. Chronic exposure to these anthropogenic compounds, many of which have no natural analog in marine systems, may lead to negative effects that are still poorly understood.”
This article is an AI-assisted summary. All facts and figures are drawn from the original report: https://www.smithsonianmag.com/smart-news/sharks-in-the-bahamas-test-positive-for-drugs-including-cocaine-and-painkillers-in-a-new-study-180988445/