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

April 22, 2012

A Positive Outlook – Problems and Solutions for Aquaculture

Filed under: Aquaculture — Tags: , , , — 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)

Sarah Beshir and Ashley Lukashevsky are undergraduates in the USC Dana and David Dornsife College of Letters, Arts and Sciences.

November 25, 2011

US Aquaculture: Feeling Fishy?

Filed under: Aquaculture — dginsbur @ 7:48 pm

With the population recently hitting seven billion, the need to provide food for the growing human race becomes more and more urgent. The amount of food available, though, is starting to decline, as the rate of intake far exceeds the natural reproductive rates of what we consume.

But omnivores, not to worry! The need to turn to vegetarianism is not quite there—the growth of aquaculture in the United States ensures that there will be enough seafood in everyday diet, at least for the time being.

The common definition of aquaculture is the farming of aquatic organisms such as fish and shellfish, which are grown to market size and released into the wild in order to support or rebuild wild stock populations. According to the NOAA Aquaculture Program, aquaculture also “includes the production of ornamental fish for the aquarium trade and plant species used in a range of food, pharmaceutical, nutritional, and biotechnology products.”

With all environmental alternatives, however, comes much debate over the proposed solution. Aquaculture faces heavy scrutiny from both scientists and the public over whether it is more beneficial or detrimental to our environment.

Currently, over 76% of world fisheries are either fully exploited, over exploited, or completely depleted, a grim outlook for the future of our diet. With aquaculture, however, the story is different, especially for the United States. The US is a major consumer of aquaculture projects; NOAA reports that “we import 84% of our seafood and half of that is from aquaculture—yet we are minor producer… Driven by imports, the US seafood trade deficit has grown to over $9 billion annually—the highest it’s ever been.” Though the US is typically at the forefront of everything, we are ranked 13th in total aquaculture production, behind countries from Europe, Asia, South America, and Africa, which explains much of the annual seafood trade deficit. By turning towards domestic seafood production, the nation’s dependence on imports will significantly reduce.

In addition to helping feed a growing US and world population, aquaculture can also “reduce fishing pressure on certain wild stocks if that species can be produced through aquaculture rather than fished,” reports a PBS document on aquaculture. And judging by the current state of our economy, more concentration in aquaculture can create jobs in communities and increase revenue on city, state, and national levels.

There are many advantages to aquaculture; however, there are some significant issues with it as well. One of the major problems with aquaculture is the threat to native fish populations. Wild fish are used to make feed for the farmed fish and often several pounds of wild fish are used to produce one pound of farmed fish. Because the fish are farmed in such a tight space, aquaculture often results in high incidences of disease, which can contaminate the waters outside of the pen threatening the native fish as well. To combat disease, antibiotics are dumped into the pens, which pollutes the surrounding waters. Fish escapes are also extremely common and interbreeding between native and farmed fish weakens the gene pool of the wild fish.

There are clear benefits and disadvantages to aquaculture. The question is: what should the US do? A New York Times article, Finding a Sustainable Way to Farm the Seas, suggests that with improvements to the industry, aquaculture could be more sustainable. Courtney Hough, general secretary of the Federation of European Aquaculture Producers, claims that “highly efficient feeds have helped bring down the ratio of fish-based feed to fish produced, sometimes to nearly one-to-one”. In addition vaccination and monitoring can help decrease the incidence of disease. There are ways to farm fish in a responsible and environmentally sustainable way. If done the right way, aquaculture could be a great solution to satisfying the protein needs of our growing population.


NOAA Aquaculture Program:


NY Times:

About the authors: Leslie Chang and Lauren Taymor are working towards their bachelor degrees in the USC Dornsife College of Letters, Arts and Sciences.