Fish Farming | A Pound of Flesh

fish farm environment pollution 03 Fish Farming | A Pound of Flesh

Fish farming – aquaculture – has taken hold as a major new industry in the world , and in this period of an ever-expanding global market, it promises to continue growing. But there are some important issues to consider when we buy farmed fish for consumption. The foremost question on my mind is “Is this a sustainable industry? Do the inputs (feed, habitat set aside for farms, etc.) equal the outputs (the amount of fish that eventually goes to market)? A second question is “Is farmed fish as healthy as wild-caught fish?” Finally, “What is the cost to the environment?”

Time magazine recently weighed in on some of these issues and uncovered the following facts:

    Nearly 40% of all fish consumed worldwide comes from aquaculture.
    The industry has grown 9% per year since 1975 and demand for species such as salmon, tuna and shrimp has doubled since then.
    To produce 1 kilogram of high-protein fish food that is fed to ocean-bred, farmed fish, it takes 4.5 kilograms of smaller fish.

fish farm environment pollution 01 Fish Farming | A Pound of Flesh

The main problem, according to Time, is that the fish being bred for aquaculture are those at the top of the oceanic food chain (salmon, tuna, cod, and shrimp) and require a tremendous input of wild fish to feed the captive fish. Estimates from show that it takes up to 5 pounds of wild fish to create one pound of farmed salmon. Salmon feed must be dyed to give the characteristic pink color, and the industry even has a fan of dye colors to simulate different types of salmon.

But that’s not the only problem. There are several environmental and health costs associated with industrial aquaculture.

Large pens of fish attract larger predators such as sharks, whales, seals, sea lions, and birds of prey. These animals must either be killed or discouraged with underwater sound devices that have been shown to have harmful effects on ocean mammals that use sonar for navigation.

There is also a problem with waste. Fish poop. According to SectionZ, an open-net farm the size of a small home produces the sewage equivalent to a town of 65,000. And this sewage passes right in to the water untreated – often in pristine coastal areas of British Columbia and Norway.

The concentration of fish in these pens is also a problem. The average 2-foot, farmed salmon gets the equivalent space of swimming a lifetime in a bathtub. The concentration and lack of motion attracts sea lice, barnacles, and epidemic disease – all of which must be treated with pesticides, algaecides, and antibiotics. These chemicals then enter the food chain in both the ocean and on land.

Finally, PCB levels in farmed fish are found at up to 10 times the levels in wild fish, although these limits are still well below FDA standards, according to Time. The greater risk is perhaps the effect of dyes, pesticides, and antibiotics – especially for children and pregnant women. Farmed fish are fattier due to less room to roam. Chemicals build up in these fats and are then passed on higher up the food chain where the effects of these chemicals are either unknown or hard to decipher.

fish farm environment pollution 02 Fish Farming | A Pound of Flesh

So, is aquaculture worth the risks? There are pros and cons to every argument. I see a similarity between the growth in industrial aquaculture and the growth of terrestrial, industrial agriculture – turning a once sun-driven industry into a fossil fuel industry. The difference here is that the land animals we cultivate are herbivores, requiring arguably less input than cultivating carnivorous fish. It seems to me that humans are again interrupting the natural cycle of growth and predation, which then forces us to inject extra resources for nominal outcomes. In terms of aquaculture, the payoff seems to come at too high of a price.

For a counterpoint to this argument from a business perspective, click here.

For other resources on aquaculture, I suggest starting here or here.

Want to get active? Pew Charitable Trust’s Oceans Commission funds research on aquaculture. So does the Goldman Fund. The Institute for Agriculture and Trade Policy studies the pros and cons of all agricultural enterprises.

  • My Name

    gay those are not cons that happends in the wild just this way u get more jobs and food

  • Shoepal74

    That photo of the fish is amazing.

  • jm

    Anyone know anything about the farmed fish sold through Whole Foods? They claim to have a superior product. 

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