The Environmental Impact of Aquaculture

Overfishing has become catastrophic.

Industrial fisheries using large commercial machinery to trawl the ocean bed result in millions of other sea animals, including whales, dolphins, and turtles, getting trapped and killed in nets —known as “bycatch“. Species such as Maui’s dolphin and North Atlantic right whale are being pushed to the very brink of extinction.

These aggressive fishing practices are emptying our oceans of life at an alarming rate. A report by the United Nations’ Food and Agriculture Organization in 2016 found that around 90 percent of the world’s fish populations are now fully exploited or overfished.

fish farming costs the earth

Now that commercial fishing has all but emptied our oceans of wild fish, the seafood industry has turned to raising fish in contained factory farms – a process known as aquaculture. These farms raise millions of fish in netted cages in coastal waters or inland pools.

Confining so many fish in small areas leads to a host of environmental and health hazards. The massive amount of faces produced by fish in these farms upsets the natural balance of the aquatic ecosystem. In some cases, the huge amount of fish excrement settling below fish cages has actually caused the ocean floor to rot. And uneaten food and feces at the bottom of the dark ponds produce such large amounts of methane that prawns are among the worst foods in terms of climate impact.

Containing so many fishes on these farms means they are prone to disease. In Scotland, for example, lice infests nearly half the salmon trapped in these sea prisons. To try to keep as many alive as possible, chemicals and antibiotics are used to try and control the spread of infectious diseases. Dead fish carcasses and uneaten antibiotic-laden fish feed —as well as being major threats to human health—pollute the coastal areas that surround these farms.

As much as 38 percent of recent mangrove loss may be due to shrimp farm development. And the once pristine sanctuary of Kolleru in India —one of Asia’s largest freshwater lakes that supplies drinking water to several island villages—has been polluted with pesticides and chemicals due to large-scale shrimp farming for export.

The irony is that while aquaculture was designed to combat the problem of overfishing, it actually contributes to the problem. This is because the fish caught and imprisoned in these farms are fed their wild-caught friends, cousins. It’s a vicious circle that’s completely unsustainable.

WHAT SHOULD WE EAT?

Both taking fish from the wild and farming them has catastrophic consequences. But we don’t need fish to be healthy, as our omega-3s can come from many sources, including seaweed, flaxseed, chia seeds, walnuts, kidney beans, edamame, and canola oil. And we can still get the fishy flavor —which is really just the taste of the sea —from many non-fish sources.

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