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July 2001
More than six billion people now live on Earth, according to a recent census study by the United Nations. These men, women, and children may not share cultures or environment, but they all share three pressing needs: habitat, water, and food.
Kuruma shrimp in an aquaculture observation tank in Taiwan. Photographer: James P. McVey; image source: NOAA
It is the need for food that has fueled the expansion of humankind and the global demand for food will only intensify as populations increase. Where will this food come from? I am concerned, as many people are, that too many farmlands may disappear in the future, limiting our food supply. In this day, farms are under siege from a variety of dangers, including urban expansion. (The irony is that these farms themselves expanded at the cost of Earth’s natural ecologies).
Since land is finite, and human hunger is not, we will have to rely more and more on the oceans. The oceans contain millions of billions of tons of seafood that is a plentiful source of protein. However, the established method of harvesting seafood — by constructing massive fleets of fishing trawlers to harvest specific species — is dangerous. Overfishing by these fleets depletes wild fish stocks and jeopardizes an ecosystem that supports a diversity of other species.
Aquaculture: a solution for dwindling farmland crops
The best alternative to fishery overharvesting is aquaculture. This kind of farming allows for a consistent harvest of seafood under controlled conditions. Aquaculture typically is practiced in coastal waters or on land whenever regular crops are not being raised.
Within the US, aquaculture is now a $1 billion industry, and globally, it is valued at $40 billion, according to the National Oceanographic and Atmospheric Agency (NOAA).
Aquaculture’s many small successes have been proven. For example:
- The oyster industry in Chesapeake Bay has been rebuilt using federal research dollars.
- In New England many local fisherman have taken up opportunities in shellfish aquaculture.
- In India, fish farming is encouraged because it improves the soil and increases rice yield in the next season.
- Even the salmon you eat has a high probability of coming from an aquaculture farm.
Can aquaculture become a viable industry?
In spite of the successes, much remains to be done to make aquaculture a viable industry:
Education
Farmers need to be educated on:
- the proper species to raise
- environmentally friendly techniques of preparing the land and raising the stock
- the diseases that afflict fish stocks and their remedies and these remedies should be made readily available to farmers
- governments should provide incentives for farmers to be good stewards of the environment
Research
Although I believe aquaculture will be successful, it is more likely to grow in small steps because more research is needed to bring it to the same level of development as land farming, especially since, for some species, the amount of marine protein used to feed them is greater than the amount produced by aquafarming. These small steps will occur as more research reveals such factors as:
- the optimal growing conditions (especially diet)
- most suitable conditions for reproduction
- survival rates
- genetically engineered aquaculture species
For example:
- My own research, which I conducted at the Florida Institute of Technology’s Aquaculture Labs, focused on how varying the fatty acid content in the diets of certain marine species affected their growth and survival rate.
- In Japan, a leading aquaculture research country, DNA was introduced last year into marine invertebrates. This could lead to the design of seafood that has more protein, tastes better, matures faster, and other qualities important to growth and consumption.
Environment
Scientists are worried about some of the disrupting consequences of aquaculture on local environments.
- The effluent of the fish stocks themselves can stimulate growth of fecal coliforms or various pathogenic bacterias.
- We could see the alteration of coastal habitats as the aquaculture or mariculture industry grows. Shrimp farming, for example, often destroys mangrove areas and it is only productive for a few years.
- There is the possibility of introducing non-indigenous species, which can result in massive damage to ecosystems.
- Few governments in the world (the U.S. included) have defined a strong policy on aquaculture operations. Global policies are urgently needed.
In conclusion
Without a viable and concentrated effort to increase protein (food) harvests by aquaculture, the Earth will soon reach a limit on how many humans it can support with land resources. According to a recent National Geographicstudy, we have less than five acres of productive land available per person worldwide to sustain us.
History has shown that when food supply is scarce, humans resort to violent means to resolve the problem. Today, there are already regional examples around the world where war and violence between factions vying for control of farmland has left thousands dead. My hope is that aquaculture will provide the means to feed the Earth’s future human population cheaply, reliably, and safely.
© 2001, American Institute of Biological Sciences. Educators have permission to reprint articles for classroom use; other users, please contact editor@actionbioscience.org for reprint permission. See reprint policy.
