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Friday, December 1, 2023

Shucking Oysters: Stoned and Confused

Shucking Oysters: Stoned and Confused

By Alex Allen

Feeling anxious, anti-social and sometimes homicidal? You are not alone. Fish and other aquatic life are also displaying drug addiction behaviour. New research has found that pharmaceuticals are contaminating waterways and oceans everywhere. With around 275 million people worldwide using drugs each year, it’s no surprise, that what goes in, must come out. 

Antidepressants are the highest-documented drugs in US waterways, which has experts worried. The most vulnerable fish populations are those downstream of sewage treatment plants, where prescription drugs consistently show up in higher levels than in other waterways. Wildlife living in rivers and coastal waters where effluent is discharged are exposed to an array of chemical cocktails.

Anti-anxiety drugs like Valium can cause fish to become more active, less social and to take more risks, making them more likely to be eaten by predators. These effects of pharmaceuticals in the waters on fish are likely permanent, because changes in brain chemistry follow exposure. So if pharmaceuticals make a fish more skittish, the fish will always be skittish, even if the drugs are removed.

In one 2018 study, blood tests and tissue analysis were used to screen bone fish, a recreation fish off the south coast of Florida. The pharmaceuticals detected included antidepressants, antibiotics, heart medications, blood pressure medications and pain relievers. The same contaminants were also found in crab, shrimp and other small sea animals that the bone fish feed on, as well as in water and sediment. Contaminants were also found in bone fish tested in waters near the Caribbean, Bahamas, Puerto Rico, Mexico and Belize.

They identified 58 different pharmaceuticals in bone fish sampled along a 200-mile stretch of the coastline over a three-year period. The pharma detected in the fish included eight different antidepressants, at concentrations equal to as much as 300 times the amount prescribed for humans.  In one case, the researchers found 16 different drugs in a single fish taken from Biscayne Bay. The study also found concentrations of Parkinson’s drugs, antifungal drugs, stomach medications and opiates in the fish.  

A US study on exposure to fluoxetine, lovingly known as Prozac, had a bizarre effect on male fathead minnows. They ignored the females and spent more time under a tile. The doses of Prozac added to the fishes’ water were very low concentrations, at 1 part per billion. When the dose was increased, at levels found in some waste water, females produced fewer eggs and males became aggressive and killed females in some cases.

Researchers in the Czech Republic deliberately tried to get dozens of trout hooked on methamphetamine for a water pollution study. The methamphetamine-exposed fish preferred the water containing the drug, while no such preference was shown for the untreated fish. The researchers also found that during their withdrawal period, the methamphetamine-exposed trout appeared extremely sluggish for about 96 hours when moved to a clean tank. 

One of the signs of drug addiction is a loss of interest in other activities – even those that are usually highly motivated, such as eating or reproducing. It’s possible that fish might start to change their natural behaviour, causing problems with their feeding, breeding and, ultimately, their survival. Exposure to drugs not only affects the fish themselves, but their offspring. In fish, addiction can be inherited over several generations. This could have long-lasting implications for ecosystems, even if the problem was fixed now.

This is not the first study to find street drugs in aquatic life. In 2019, scientists in the UK reported cocaine in freshwater shrimp in all 15 rivers they sampled. Interestingly, they detected illegal drugs more often than some common pharmaceuticals. US scientists discovered traces of opioids in mussels off the coast of Washington in 2018. Canadian researchers also found traces of cocaine in the discharge from water treatment plants in southern Ontario in 2015. Sewage treatment plants don’t filter these things out – they were never designed to. 

And if that’s not enough, we have sharks hooked on cocaine. Florida is a major transit point for drugs entering the US from South America, and the region is a hot spot for floating cocaine bales which are often lost at sea or discarded by traffickers. Last summer, a research team in the Florida Keys, observed sharks displaying unusual behaviours. Researchers are speculating that sharks, driven by hunger and frenzy, might be consuming the packages off the coast of Florida.


A hammerhead, a species that would typically avoid humans, approached the divers directly, moving erratically. They also noticed a sandbar shark swimming in circles, fixated on an imaginary object. The researchers dropped dummy bales in the water, which many of the sharks bit into, and loaded balls of bait with highly concentrated fish powder to simulate cocaine. The effect, the researchers noted, was similar to the impact of catnip on cats.

Last month, the US Coast Guard announced the recovery of over $186 million of illegal narcotics from the waters of the Caribbean and southern Florida. Apparently, such seizures barely make a dent in an industry operating at record levels. 

It’s not just drugs in our waters. Plastics. Heavy metals. Chemicals. All our shit. We need to urgently take action to protect our oceans and the diverse life they support. Our actions on land have far-reaching consequences for the health of our oceans and waterways. Remember, as Paul Simon wrote, one man’s ceiling is another man’s floor.

Author: TIG

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