Trends in Aquaculture Reduce Environmental Risks, Report Finds

Bluefin tuna stir the waters inside a deepwater pen in Mexican waters.

Washington — Commercial aquaculture can be a profitable and environmentally sustainable activity if conducted with the right methods in the right waters, according to a report issued by the U.S. National Oceanic and Atmospheric Administration (NOAA).

Scientists at NOAA’s National Ocean Service reviewed more than 400 scientific papers on aquaculture practices at locations around the world, focusing on the potential impacts fish farming might have on water quality, sediment chemistry, marine life and benthic communities — that is, ecosystems of plants and organisms living on the floor of an aquatic environment.

Practices in various localities consistently show that “farming with minimal or acceptable environmental effects is possible in many ecosystems as long as proper safeguards are in place to minimize nutrient and chemical discharge and to manage its immediate and cumulative impacts,” according to the report, Marine Cage Culture and the Environment.

The report notes that changing trends in aquaculture practices have lowered the number of water-quality problems from the number detected in the early years of the industry. Farms that are located in deep, well-flushed waters can usually avoid creating risks for the water quality of benthic communities.

If waters are not well flushed and sufficiently deep, feeding the caged fish can lead to excessive accumulation of nutrients and wastes, which endangers the balance necessary to sustain wild populations. Locating farms near shallow water or in semi-enclosed water bodies is likely to create water-quality issues, the report finds.

About half of all fish consumed globally are produced in farms, and the amount is likely to increase to meet the world’s demands for protein. Overfishing of many traditional fishing grounds has depleted native supplies just as expanding populations and greater affluence create a demand for more fish in the markets.

The United States has not entered aquaculture with the same level of investment as many other nations, the report says, largely because of uncertainty in state and federal regulatory practices and potential conflicts with other users of coastal waters. The report says the United States has the appropriate resources and capability to expand the industry aggressively.

While practices to minimize environmental damage have improved markedly, the report finds, continued scientific monitoring is recommended because “questions remain about far-field effects over large time scales.”

The Aquaculture Department of the Food and Agriculture Organization of the United Nations (FAO) reports that aquaculture production of food fish neared 63 million tons in 2011, the latest year for which data is available. The estimated value is $130 billion, the FAO reports. The industry includes about 560 different species, dominated by almost 350 species of fin fish.

Global aquaculture production has been steadily rising in recent years, with annual increases in the range of 5 percent to 6 percent. Asia is by far the largest producer, according to FAO data, responsible for 88 percent of global production. The Americas and Europe are the next leading producers, each having an output under 5 percent of global totals.