Part II - Aquaponics in New England

Part II of Aquaponics in New England discusses how aquaponics can improve the sustainability of produce and fish production. A PDF of the entire paper (Parts I-III) can be downloaded here, including a full list of sources referenced by footnotes. 

Improve Sustainability of Local Harvest

Water Use

In addition to providing a sustainable source of fish, aquaponics has other sustainability advantages over traditional farming, hydroponics, and aquaculture. First, these techniques use a lot of water. Traditional aquaculture methods use between 0.57 and 33 cubic meters (m³) of water produce 1 kilogram (kg) of fish, depending on method⁸ (See Table 2). Research at the University of Virgin Islands has shown that their aquaponics system uses less than half of the water of the most productive aquaculture systems: 0.25 m³/kg.⁸ On average, aquaponic systems use between 90 and 99% less water than traditional aquaculture systems.⁹

 

Aquaponics also uses less water than hydroponic crop production. Aquaponic systems...
can last up to a year or more without a full water change, whereas hydroponic systems need water changes about every three months.⁹  The salt and other waste products that accumulate in hydroponic systems also constitute a potentially harmful waste product.

Compared to traditional farming, aquaponics also uses much less water. The United Nations Environmental, Scientific, and Cultural Organization finds that to grow a one-pound head of lettuce requires an average of 15.9 gallons water. Analysis of data from the University of Virgin Islands shows that their lettuce required less than half that amount of water: 7.6 gallons per pound. And remember that the same water produced 11,000 kg of fish, too. ⁹

In verdant New England, water conservation – or lack thereof – might not seem a major issue; however, it will soon constitute one of the most important characteristics of an agricultural operation’s profitability and sustainability. Already, the region faces chronic water shortages in the summer, and population growth and climate change will exacerbate the problem.

Unfortunately, lack of major governmental action to limit GHG emissions has made significant climate change inevitable.¹⁰ In the coming century worldwide, we will see higher peak temperatures, scarcer water, higher sea levels, and higher intensity storms. In New England, the effects will be similar. The region actually will see more precipitation, but it will come in sporadic, heavy downpours as opposed to regular showers, with a higher likelihood of droughts in between.¹¹ Since 1970, the region has already experienced an increase in the heavy precipitation events, combined with decreased snowpack and earlier spring floods.¹² Less water is and will continue to be available when crops need it in the region.

Combined with the stress of population growth, water will be at a premium. A study by engineering firm Tetra Tech modeled the combined effects of climate change and population growth on water scarcity in US counties and found that by mid-century, one third of all counties in the lower 48 will face higher risks of water shortages than they do now; nearly half of those will face extremely high risks.¹³ In Massachusetts, six (43%) counties will face moderate to high risks for water shortages (See Table 3). These counties currently account for $138 million in agricultural production.13

Other Sustainability Advantages of Aquaponics

Additionally, traditional non-organic farming uses many chemical inputs like pesticides, fertilizers, and herbicides. The production and use of inorganic fertilizers are unsustainable in many regards. They do not typically replace trace minerals in soil; they use massive amounts of fossil fuels, especially in the synthesis of nitrate fertilizer (i.e. Haber process); and the nitrogen fertilizer applied contributes to build up of the GHG Nitrous Oxide in the atmosphere.^14,15 Pesticides and herbicides are typically produced by fossil fuels, too, and their application can have negative environmental impacts. Similarly, the nutrient solutions used by commercial hydroponics operations contain chemical components often derived from fossil fuels, are manufactured using fossil fuels, and typically use fossil fuels in their transportation to the hydroponic facility.^16,17

By definition though, aquaponics is organic. As a closed-loop system, aquaponics cannot use pesticides, fertilizers, or herbicides, because the chemicals would harm the fish.  Additionally, the nutrients are produced on site by the fish, eliminating the need for transportation of nutrients found in hydroponics. As for waste from aquaponics, the organic solids (i.e. fish waste) can be used as fertilizer for field crops or other plants, as is done in University of Virgin Islands.

Further, aquaponics minimizes land use. Whether organic or not, traditional farming requires more land to produce an equal amount of food. First, aquaponics is more productive per square foot. At the University of Virgin Islands, Rakocy et al (2004) tested basil and okra production in aquaponics and in fields. They found that per square foot of growing area, the aquaponic method was three and twenty times more productive than the field production of basil and okra, respectively.¹⁸ Their productivity test did not account for the added benefit that aquaponics can produce year round, further increasing its productivity per square foot in regions like New England. Additionally, innovative setups, such as vertical farming, can improve productivity further. By producing food on a much smaller footprint than traditional farming, more land remains open and available to protect as natural habitat or to use toward other beneficial societal uses.

Click to continue to Part III!

Sources
See a complete list of sources by downloading the PDF here.