Fish, drugs and the environment

The catch-22 of fish farming: Feed the people or save the fish?

Author: Aisha Farida Aminu
Editor: Bethany Evans
Artist: Lucie Gourmet


Unless we personally go fishing, we don’t really know where the fish we eat come from. With the dawn of mass food consumption, most of the fish we eat do not come straight from natural bodies of water. Rather, about half come from fish farms, which are large fish-breeding enclosures located on land or in water bodies like lakes, rivers and seas.

You might think that fish farming is a good thing and would help to protect the fish in open water from over-fishing, but in reality, this is not the case. The need for humans to control and simplify complex natural systems for their own benefit is detrimental in the long run. For example, most of the fish we get from fish farms are carnivorous and eat wild fish from open waters to survive. So, even though humans are eating less wild fish, the pressure on wild fish populations has risen. A striking example is the Atlantic salmon, an intensively farmed fish species. To breed just one salmon on a fish farm, 500 anchovies (a small type of fish) are required as fish-feed.

Farmed fish jeopardise the health of wild fish populations in many more ways. Due to their dense enclosures, farmed fish are highly susceptible to communicable diseases and parasitic infections. Farm-bred salmon act as hosts to sea lice and easily transfer these parasites to other fish within their surroundings when the farms are located in open waters. In addition, pesticides used to control these parasites, fish faeces and other waste from fish farms can contaminate surrounding water and negatively impact the health of wild fish. Furthermore, when salmon escape from farms, they compete for food and breed with wild fish. As farmed fish are not adapted to open waters, their offspring as a result of interbreeding with wild fish are less likely to survive. Cumulatively, these processes have the potential to drive wild salmon populations to extinction.

Another issue with fish farms is drugs. Who would have thought we’d be telling the kids to stay away from drugged-up fish? Fish are popular for their nutritional benefits such as high levels of protein, omega-3 fatty acids, vitamins and minerals. Yet when humans eat farm-raised fish, they also consume a high level of antibiotics, pesticides, artificial dyes and other chemicals. An American study also found that drug residues in wild fish exceeded normal safety levels, owing to the absorption of antibiotics and pesticides that leak out of fish farms.

The consumption of fish that have been exposed to high amounts of antibiotics may also contribute to the rise of antibiotic-resistant bacteria, which makes it increasingly difficult to treat many human illnesses. The antibiotics used in fish farms can also directly harm human health. Studies have shown that commonly used antibiotics such as chloramphenicol and nitrofurans may be linked to increased risk of cancer in humans. Other unsafe drugs used in fish farms have also been linked to behavioural and growth impairments and brain development issues in children. Drug regulations for fish farming vary from country to country and these regulations are usually undermined by inadequate record-keeping on the farms.

Fish farming also has environmental consequences. Studies in the early 2000s that sampled farm-raised salmon in various countries found contaminants such as polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethane (DDT), dioxins and chlordane at high concentrations. PCBs and dioxins are profoundly toxic man-made chemicals that resist biodegradation and accumulate in the environment, polluting natural habitats. The institution of fish farms in open waters also encroaches on natural coastal habitats and mangrove swamps, inhibiting ecosystem functions like flood defence and water filtration.

As fish farming is not likely to abruptly end nor are we likely to stop eating fish entirely, consumers must make informed decisions about the fish we buy and eat. We should seek out shops and fish markets that clearly label the origins of their seafood and put pressure on governing bodies to properly enforce regulations that protect our fish and by extension, our health. EU environmental regulations are forcing fish farms to reduce the release of pollutants into the environment, safeguard the health of fish populations, and clearly label the ecological impact of their fish products. As consumer awareness continues to rise and government regulations become even more stringent, perhaps there will come a time when fish farming will be an entirely eradicated practice.

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