News Briefs
Will fish farms feed the world?
COURTESY OF RANDALL OSTERHUBER
Aquaculture is the world’s fastest growing source of food, according to a report released in October by two nonprofit organizations, the International Food Policy Research Institute (IFPRI) and the WorldFish Center. They predict that the production of farmed fish will nearly double by 2020, when aquaculture will be the source of more than 40% of the fish eaten by consumers. But they warn that new technologies are needed to reduce the environmental impact of fish farming.
Intensive shrimp production systems such as this one in Sinoloa, Mexico, have altered coastal systems by removing native flora like mangrove trees.
Fish to 2020: Supply and Demand in Changing Global Markets is the first report to inject an economic perspective into an analysis of what is broadly acknowledged to be an industry in crisis. The report uses modeling data to predict that developing countries will be responsible for 77% of the world’s global fish consumption and 79% of the world’s fish production by 2020. This prediction is significant because the projections hold that fish consumption will grow by 57% in the developing world to 98.6 million metric tons in 2020. During the same period, fish consumption in the developed world is expected to grow by only 4%. The policies crafted now could have a significant impact because
40% of fish is traded internationally—far more than any other foodstuff, says Meryl Williams, director general of the WorldFish Center. How fish are farmed has consequences for ocean fisheries because one-third of all fish pulled out of the ocean are used to produce the fishmeal used to feed aquacultured fish and livestock, says Nikolas Wada, a senior research assistant at IFPRI. “Aquaculture could consume nearly all of the world’s fishmeal and oil in 20 years,” Wada says. For every kilogram of farmed fish, 1.3 kilograms of wild fish are required in the form of fishmeal and oil, adds Rebecca Goldburg, a senior scientist with Environmental Defense, a nonprofit organization. The stocks of the small pelagic fish that make up the bulk of this fishmeal are important foods for marine predators, Goldburg says. Moreover, they are also likely to become increasingly important food for humans, she adds. Further complicating the situation is the reality that the supply of these small pelagic fish drops precipitously every several years in response to the El Niño/Southern Oscillation that affects ocean currents, Wada says. Fish-based fishmeal can also introduce fat-soluble contaminants, like heavy metals and PCBs, into aquaculture diets (Environ. Sci. Technol. 2002, 36, 267A−268A), Wada says. Certifications attesting to the health of fish stocks will become an increasingly important trade issue, he predicts. The fishmeal’s protein content can be replaced by plant-based species relatively easily, but replacing the oil content is more difficult, Williams says. Although anywhere from 11 to 15% of fishmeal currently comes from the byproducts of seafood processing, there is a move to make increased use of these byproducts, Goldburg says. Fish farms often require saltwater or freshwater ponds, which can necessitate converting land
Biorefinery for industrial chemicals The U.S. Department of Energy’s National Renewable Energy Laboratory (NREL) and DuPont have signed an agreement to develop the world’s first integrated “biorefinery” that uses renewable resources to produce fuels and industrial chemicals instead of petroleum. The $7.7 million Cooperative Research and Development Agreement calls for DuPont and NREL to collaboratively design, build, and test a pilot biorefinery process that will make fuels and chemicals from the entire corn plant. This initiative aims to develop the first fully integrated biorefinery capable of producing a range of products from a variety of plant-material feedstocks. For more information, go to www.nrel.gov.
New green engineering grants The major governmental funding source for green engineering projects is the Technology for a Sustainable Environment (TSE) program, agree researchers in the field. The program is a partnership between the U.S. EPA and the National Science Foundation. In October, TSE announced 34 new grants totaling approximately $11 million, including research at Michigan State University on catalytic reactions needed to create the “biomass refinery” of the future; work at the University of Arkansas at Little Rock to develop chromate-free, corrosion-resistant coatings; and efforts at the University of Kansas Center for Research, Inc., to devise supercritical CO2 solvents. Since the partnership began in 1995, it has dispersed more than $58 million in funding for more than 189 projects. For more information, see www.eng.nsf.gov/tse/ or http:// cfpub.epa.gov/ncer_abstracts/ index.cfm/fuseaction/outlinks.rfa.
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Environmental▼News from another use. The decimation of Thailand’s mangroves to create shrimp farms is just one example of why this can be a problem, Wada says. Freshwater and saltwater wastewater from fish farms can also pollute both land and water. Escaped farm fish can wreak environmental havoc, too, Wada says. Salmon and tilapia from farms have bred with native stocks on almost every continent, he says. Scientists are concerned that escaped salmon could alter the genetic diversity of stocks of wild salmon with interbreeding, says Cathy Roheim, a professor in the University of Rhode Island’s Department of Environmental and Natural Resource Economics. Some of the research under way to decrease the environmental pressures caused by aquaculture includes efforts to raise saltwater fish in freshwater or saltwater with very low salinity, according to the Harbor Branch Oceanographic Institution of Ft. Pierce, Fla. U.S.
researchers are also investigating technologies for developing closed aquaculture systems that do not release polluted water and aquaculture methods that use energyefficient technologies, such as solar power. However, much of the current technology for sustainably improving the efficiency of aquaculture tends to be capital-intensive, says Christopher Delgado of IFPRI, lead author of the report. Many of the developing countries in which the majority of the growth in aquaculture is expected can’t afford expensive technologies, he says. The WorldFish Center is one of the organizations investigating inexpensive ways to increase the efficiencyand thereby reduce the environmental impactof aquaculture, Williams says. Fish can be selectively bred to increase rates of growth; their food can be enhanced so that they use it more efficiently; and farm management can be improved, she says. In Africa, for ex-
ample, researchers have bred strains of Nile tilapia that grow 100% faster, which has brought down prices. By identifying which fish are captured and raised using approaches that are less damaging to the oceans and environment, labels such as the Marine Stewardship Council’s MSC logo, which designates sustainably managed fisheries, can play an important role. David Freestone, chief counsel at the World Bank, urges developed countries to support these labels. However, developing countries may not have the resources required to put effective management systems in place, Roheim warns. “It takes a lot of money to gather data on current populations of fish, estimate maximum sustainable yield, create management regulations with someone to enforce them, work with all stakeholders of the fishery, protect marine mammals and other sea life, and so on,” she says. —KELLYN BETTS
Swedish engineers have virtually eliminated polluted runoff from Hammarby Sjöstad, the largest residential and commercial development in the city of Stockholm, thanks to a built-in system of infiltration beds and settlement tanks. Gutters and small canals that run through the parks between the apartment buildings collect clean rainwater from roofs and lawns for later use on gardens. Polluted runoff from streets and parking lots runs into tanks, where particles settle out, after which it flows into filtration beds, which remove nutrients. The cleansed water then streams into the canals and out into Hammarby Lake. The runoff controls are just one part of a plan to cut pollution and water and energy use by 50%, compared to residences and businesses built in 1990, for the redevelopment of this 1.5-square-kilometer industrial brownfield site. Energy is provided from solar and hydrogen fuel cells, bio-gas from the sewage
VICTORIA HENRIKSSON
Swedes showcase runoff-free development
plant, two power plants that run on garbage and bio-fuels (pine needle oil), and a heat exchanger that extracts heat from treated wastewater. A pilot sewage treatment plant that treats only toilet and “gray”, or washing water, opened October 16.
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The sludge from the plant will not have the high levels of metals and other pollutants that plague sludge from industrial sources. Read more about Hammarby Sjöstad at www. hammarbysjostad.stockholm.se. —JANET PELLEY
