Are Fish Farms the Answer in Supplying Our Growing Population?

There is a great controversy surrounding production through fish farms as opposed to a reliance on wild fish sources. Wild fisheries populations are declining, however aquaculture<!–[if supportFields]> XE “aquaculture” <![endif]–><!–[if supportFields]><![endif]–> could become the most sustainable source for protein for humans. Currently there is a reliance on meat from livestock, and food consumption is increasing worldwide. The population is estimated to increase from an already high 6.9 billion to 9.3 billion people by 2050. With this in mind, the question arises about where global meat will come from. Raising livestock uses up a vast amount of land, freshwater, fossil fuels, and results in organic waste and fertilizer<!–[if supportFields]> XE “fertilizer” <![endif]–><!–[if supportFields]><![endif]–> run-off that has a negative impact on rivers and oceans. These same issues apply to fish farming and other aquaculture, which results in fish sewage, depletion of mangrove forest<!–[if supportFields]> XE “forest” <![endif]–><!–[if supportFields]><![endif]–> for shrimp growth, and densely packed salmon<!–[if supportFields]> XE “salmon” <![endif]–><!–[if supportFields]><![endif]–> farms that cause disease and parasites<!–[if supportFields]> XE “parasites” <![endif]–><!–[if supportFields]><![endif]–>, which kill off their populations and infect native species as well. Larger offshore pens are much cleaner and could serve as a place for expansion of aquaculture and could even become more sustainable than wild fish or raised beef. —Lauren Lambert
Simpson, S., 2010. The Blue Food Revolution. Scientific American 304, 54–61

Simpson (2011) addresses the benefits of aquaculture<!–[if supportFields]> XE “aquaculture” <![endif]–><!–[if supportFields]><![endif]–> and fish farming as a solution to the global food security issue. Coastal fish farms pollute the ocean with fish excrement and food scraps, particularly in the shallow waters. Offshore sites such as Kona Blue Water Farms have eliminated the pollution issue by submerging paddocks that are anchored in the presence of rapid currents that quickly dilute and sweep away the harmful waste before it can become a problem for marine ecosystems nearby. These paddocks are cone shape and made from solid material that is strong enough to keep sharks from getting into the fish supply. They contain massive amounts of domesticated yellowtail, which serve as an alternative to wild tuna. These fish are fed pellets of fishmeal and oil made from smaller fish. The yellowtail could survive on a purely vegetarian diet, but their meat would not contain the fatty acids and amino acids<!–[if supportFields]> XE “amino acids” <![endif]–><!–[if supportFields]><![endif]–> that produce a healthy, good tasting fish. Other farms raise seaweed and filter feeding animals such as mollusks near the fish pens to use up the waste. Cutting edge designs for fish pens are submerged, steered by large propellers, and ride on ocean currents to stimulate fish maturation. The pens would then return months later to the starting point or designated destination for delivery of fresh fish to market.
The fishmeal used to feed the fish farms is of concern because of the rapid decline of smaller fish species such as anchovy<!–[if supportFields]> XE “anchovy” <![endif]–><!–[if supportFields]><![endif]–>. Anchovy concentration in feed pellets were reduced from containing 80% in 2005 to 30% in 2008 by adding a higher concentration of soybean<!–[if supportFields]> XE “soybeans” <![endif]–><!–[if supportFields]><![endif]–> meal and chicken oil. However as the demand for fish farms increases, sardine and anchovy populations are in jeopardy of a decline in population size. Aquaculture is the fastest growing food production sector in the world, expanding at a rate of 7.5% per year since 1994. At this rate, fish and all of its products could be exhausted by 2040 and therefore, the main goal is to eliminate the use of wild fish from feed products altogether. One possible solution is to use docosahexaenoic acid (DHA) from microscopic algae because of the need to eliminate all agricultural resources from feed, and push towards a reliance on easily grown seaweed and zooplankton<!–[if supportFields]> XE “zooplankton” <![endif]–><!–[if supportFields]><![endif]–>.
The world health organization predicts a 25% increase in meat consumption by 2050. Simpson leans towards aquaculture<!–[if supportFields]> XE “aquaculture” <![endif]–><!–[if supportFields]><![endif]–> for the global protein supply. Cattle eat a large amount of heavily fertilized crops, and pig and chicken farms are extremely polluting to the environment. Raising Angus beef requires 4,400 times more high quality pastureland than seafloor needed for the equivalent weight of farmed Atlantic salmon<!–[if supportFields]> XE “salmon” <![endif]–><!–[if supportFields]><![endif]–>. However fish farms also have their flaws. Areas below coastal fish farms have huge dead zones, similar to the results of fertilizer<!–[if supportFields]> XE “fertilizer” <![endif]–><!–[if supportFields]><![endif]–> run-off from the Mississippi River into the Gulf of Mexico<!–[if supportFields]> XE “Gulf of Mexico” <![endif]–><!–[if supportFields]><![endif]–>, or harmful algal blooms from pig farms in the Chesapeake Bay. Although fish farms are relatively detrimental to ecosystems, marine ecosystems have the ability to recover in less than a decade, whereas a cattle farm would take centuries to overcome the damage.
Fish farming reduces the size of marine fishing fleets, so that although fuel consumption and emissions are higher on an offshore farm, they are not as high as would result from fleets catching equivalent amounts of wild fish. Aside from these advantages, inefficient and harmful fishing methods such as trawling and dredging kill millions of animals as bycatch, that are regarded as worthless and tossed aside. Fish farming is also more efficient in that the raised fish do not have to waste energy searching for food, avoiding predators, and reproducing. Most of their diet goes into growth, so they mature at a faster rate.

Fish farming already accounts for 47% of global seafood consumption, and could potentially rise to 62% of total protein supply by 2050. Although there are many benefits to this method of food production, society is not yet ready to switch to these measures. But Americans do not yet accept this transition to an increased reliance on aquaculture<!–[if supportFields]> XE “aquaculture” <![endif]–><!–[if supportFields]><![endif]–>; the public accepts domestication on land, but has a perception of the ocean as a wild frontier. Perhaps at some point this will change. 

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