USC Dana and David Dornsife College of Letters, Arts & Sciences

April 22, 2012

A Positive Outlook – Problems and Solutions for Aquaculture

Filed under: Aquaculture — Tags: Aquaculture, over-fishing, RAS, salmon — dginsbur @ 9:42 pm

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