Sharks on Cocaine: The New Oceanic Threat You Didn’t See Coming

What lurks beneath the ocean’s surface? Well, prepare to be shocked. Brazilian researchers have made a startling discovery: cocaine sharks. That’s right, cocaine. 

A recent study has revealed the presence of cocaine (COC) and its metabolite, benzoylecgonine (BE), in the muscle and liver tissues of Brazilian sharpnose sharks.¹ 

Here’s what the researchers found.

What are Sharpnose Sharks? 

The Brazilian sharpnose shark (Rhizoprionodon lalandii) is a small species of requiem shark found in the tropical waters of the western Atlantic Ocean, including the coast of Brazil. They are characterized by:

• Size: They typically reach a length of 30 inches, making them one of the smaller shark species.
• Habitat: They are primarily coastal dwellers, preferring shallow waters close to shore.
• Diet: Their diet consists mainly of small fish, crustaceans, and squid.
• Behavior: They are relatively shy and non-aggressive towards humans.
• Conservation Status: While not globally threatened, they are considered vulnerable in Brazil due to overfishing and habitat degradation.
• Importance: They play a vital role in maintaining the balance of marine ecosystems by regulating prey populations.

The first COC and BE report for free-ranging sharks worldwide features the discovery of cocaine in Brazilian sharpnose sharks, which has raised concerns about the impact of pollution on these creatures and the risks to human health due to their consumption.

Study Analyzes Brazilian Sharpnose Sharks

From September 2021 to August 2023, a research team investigated the potential impact of cocaine pollution on marine life. They focused on 13 Brazilian sharpnose sharks (Rhizoprionodon lalandii), captured off the coast of Rio de Janeiro. 

This species was chosen due to their preference for coastal habitats, making them susceptible to human-generated pollution.

Cocaine Found in Every Shark Sample

Researchers measured the weight and length of each shark before dissecting them to obtain muscle and liver samples. Alarmingly, every sample tested positive for cocaine, with 92% of muscle samples and 23% of liver samples also containing benzoylecgonine, a major cocaine metabolite. 

This groundbreaking discovery marks the first documented case of cocaine found in free-ranging sharks.

Potential Impacts on Sharks & Humans Remain Unclear

While the study confirmed cocaine presence in sharks, the effects of this exposure remain unknown.

Previous research on other fish species, such as eels and zebrafish, has shown that cocaine can alter proteins, affect skin health, and disrupt hormone function.

Researchers Call for Further Investigation

To fully understand the potential ecological and health risks, the research team urges expanded environmental monitoring of drug pollution along the Brazilian coast. 

They emphasize the need for detailed studies on the effects of cocaine on marine life and the potential risks it poses to human health.

Potential Risks to Human Health

The presence of cocaine in sharks raises concerns for human health, as shark meat is widely consumed in Brazil and globally.

Although there are no established safety limits for cocaine in food, the findings highlight a potential risk, especially in regions like Rio de Janeiro where shark consumption is common.

Proactive Measures Needed to Protect Marine Ecosystems

Further research is key to assess the full impact of cocaine on sharks and humans. However, the research team stresses the urgency of taking proactive measures to address this emerging issue. 

The researchers from the study recommend implementing strategies to reduce cocaine pollution and mitigate the associated ecological and public health risks, ensuring the long-term health and balance of coastal ecosystems.

Source:

1. Science of The Total Environment