April 22, 2012
A Positive Outlook – Problems and Solutions for Aquaculture
Today, more than 32% of world fish stocks are overexploited or depleted while and 1 out of 5 people rely on fish as their main source of protein. This is not sustainable considering the projected increase in global population. One potential solution to the imminent shortage of ocean protein is aquaculture. Aquaculture, or the farming of aquatic organisms including fish, mollusks, crustaceans and aquatic plants, is increasing at a faster rate than all other animal protein production. From a stable source of food supply to local economic benefits and career opportunities, it offers a vast array of benefits that society can certainly benefit from. But at what costs? There is controversy over whether the challenges of aquaculture, including marine degradation, outweigh the benefits of this technology. Overall, considering economic and humanitarian concerns, in addition to the various means by which the problems with aquaculture can be mitigated, the benefits might prove to outweigh the costs.
Some of aquaculture’s most significant benefits are it’s economic, societal, and environmental contributions. Economically, aquaculture can help meet the global demand for food, and it is simply very efficient. For example, in finfish aquaculture, one ton of feed produces almost one ton of this fish, compare this to the 150 kilograms of beef, 300 kilograms of pork, and 500 kilograms of chicken the same amount of feed would produce. Aquaculture, in addition to feeding people, boosts local economy and can therefore be seen as a possible path for many developing nations. For example, in Vietnam’s aquaculture plan will create 3 million jobs, generate $4 billion in exports. Societally, sustainable aquaculture has proven to facilitate women involvement, one example is the M.S. Swaminathan Research Foundation. Environmentally, aquaculture eases strain on natural population of fish in oceans.
Aquaculture’s most significant challenges have to do with its effect on the environment. In land based fish-farms, introduced species can become invasive species in nearby waterways, for example, aisian carp used by catfish farmers downstream have invaded the length of the Mississippi River. Escaped fishes can also infect and reduce genetic diveristy in native populations. from Other concerns are specific to pfaarticular highly demanded species, like salmon. Salmon are carnivorous so its feed is comprised of other fish (e.g. sardines, herrings), but harvesting feed further strains ocean ecosystems. Another major issue with aquaculture is that of waste; open aquaculture system release nitrogen, phosphorus, parasites and fecal matter into nearby coastal water and can contaminate the seabed and shellfish that live there.
There are a plethora of innovative solutions to problems with aquaculture, ranging from specific technologies to broad industry strategies. Some sustainable technologies solve multiple problems; for example, recirculating aquaculture systems (RAS) use 99% less water than other systems, have a low space demand, eliminate the need for antibiotics and chemicals, minimize the discharge of waste, and prevent fish and parasite escapes. Another solution is integrating rice and fish farming, in which fish fertilize soil used for rice production while eating troublesome weeds and algae. Rice-fish farmers have 5-11% higher revenue, and it is particularly well suited for regions like Bangladesh, where rice farming alrady dominates agricultural land use. Other solutions include technical advances in hatchery systems, feeds and feed-delivery systems, and disease management in addition to cheaper food substrates via use of genetically modified organisms. Overall, the most important suggestion for the future of aquaculture is greater than ecological technologies alone, the solution for this and many other human induced environmental issues is in the development of comprehensive management strategies that balance human need with that of the natural environment.
Other Sources:
Food Security: The Challenge of Feeding 9 Billion People H. Charles J. Godfray, et al. Science 327, 812 (2010)
http://www.aims.ca/site/media/aims/davis.pdf
http://www.fao.org/docrep/003/x6947e/x6947e09.htm
http://www.fis.com/fis/worldnews/worldnews.asp?monthyear=&day=12&id=51367&l=e&special=&ndb=1%20target=
http://www.heraldtribune.com/article/20120416/article/120419696?p=4&tc=pg
http://www.nature.com/scitable/knowledge/library/aquaculture-challenges-and-promise-23690921
http://www.oceancommission.gov/publicomment/novgencomment/costa_pierce_comment.pdf
http://www.seafoodsource.com/newsarticledetail.aspx?id=4294987322
http://www.uq.edu.au/news/?article=24603
http://www.zambotimes.com/archives/46316-Aquaculture-industry-boosting-panggasius-output.html
Sarah Beshir and Ashley Lukashevsky are undergraduates in the USC Dana and David Dornsife College of Letters, Arts and Sciences.
I found the solutions to aquaculture’s problems very interesting. There are so many positives that aquaculture can provide for international economies, food sources, job opportunities, and sustainable fisheries. Thus, I think that more research should be done in order to iron out the challenges that it also brings such as contamination of wild populations, waste disposal, and impact on pre-existing fisheries. Going forward, if multiple issues can be solved with fewer solutions I feel that more effort should be put into those tactics such as integrated rice and fish farming. For economically vulnerable areas, this can be a life-saving solution for many people. However, I do think that climate change should be considered as aquaculture becomes more prevalent and reliable. For instance, what will happen to aquaculture fisheries when sea levels begin to rise? What happens if the entire land mass is consumed in water? How then will the aquaculture be farmed? If research is conducted with problems such as this in mind I think that aquaculture will be the way of the future for many people’s main source of protein.
Aquaculture has a lot of potential as a new emerging industry in less developed countries. As this blog stated, many of the planet’s natural populations of fish have been overexploited due to overfishing from a lack of government regulation, and aquaculture can be a sustainable solution to not only take the pressure off of marine fish populations but also to prevent the depletion of current healthy populations.
However, the initial investment to starting an aquaculture farm whether marine or terrestrial, as both freshwater and saltwater fishes can be farmed, is large, and small farmers often require government assistance to develop responsible farms. One sustainable farming method that is currently being employed by the farmers in Western Ghana is the integrated farm. These farms unite the agricultural and aquacultural components to produce a farm that is sustainable and provides food security to the impoverished region. The farms build ponds in waterlogged land that can’t be used to grow vegetables or other crops, and the ponds are filled naturally by the water table. The farms use chicken excrement to fertilize the ponds and grow algae for the tilapia and catfish to feed on. Also, unusable scraps from the farm are used as feed, reducing overall farm waste. After harvesting is complete, the nutrient rich sediment at the bottom of the ponds is used to fertilize the farmer’s crops. Also, because the ponds are terrestrial there is no possibility of fish escapes or parasite introduction. However, in the eastern part of the country there are commercial marine based aquaculture projects that have begun to harm the natural environment because they do not have adequate water quality treatment facilities to prevent eutrophication from fish wastes and excess feeds. There is great potential for sustainable aquaculture, however it needs to be implemented with regulations.
Cite:
Brummett, R.E. and Lazard, J. and Moehl, J. African Aquaculture: Realizing the Potential. Food Policy, 181(1-2):37–59, 2009.
http://www.bluekitabu.org/blue-kitabu-research-instit/
I would like to look at little further into the technique of combining agricultural crop production in water (hydroponics) with fish farming (aquaculture). Aquaponics, as this system is termed, is considered to be a developing technology, although its roots can be traced back as far as the Aztec Empire. The idea is that the nutrients in the fish waste water can be used to water the plants, which absorb the nutrients and filter many possible toxins, allowing this water to be collected under the plants, aerated, and recycled back into to the fish habitat. Acting as a mostly closed system, this technique not only conserves water, it also greatly reduces two major sources of nitrogen to the global nitrogen cycle. Instead of being released to the ocean, the fish waste is utilized by the plants, which in turn do not require additional fertilizers which normally run into ground or surface waters causing problems with contamination and eutrophication. A new popular product on the market includes backyard aquaponics. People can purchase the system, have it installed in their backyard, and consume what it produces every day. The system is still very expensive initially, but after it is set up, the only cost would be the very small amount of inflow water to account for the water lost by evaporation and to plants, and fish food. On the larger scale, farms in North and South America, Asia, and Australia have implemented the technique. The most commonly used fish is freshwater rainbow trout. There are many crops that grow well in the system including almost all leaf green vegetables, beans, peas, radishes, strawberries, melons, onions, sweet potatoes, and most herbs. Because I love gardening, if this product were to become more affordable, I would recommend that every family buy one. One day when I have my own house, I might try to even make one on my own!
Sources:
friendlyaquaponics.com
Backyardaquaponics.com
http://www.aces.edu/dept/fisheries/aquaculture/documents/309884-SRAC454.pdf