Aquaculture is the fastest growing sector of the world food economy, increasing by more than 10% per year and currently accounts for more than 30% of all fish consumed. While most farmed fish are vegetarian species, such as carp and catfish, farming of carnivorous species, such as salmon, is a booming industry and the number of other farmed carnivorous species is growing rapidly. However, industrialized farming of carnivorous fish such as salmon requires the intensive use of resources and exports problems to the surrounding environment. Detrimental effects include: displacement of wild fish populations; harmful genetic interactions with wild fish; transfer of parasites and disease; discharge of untreated wastes into coastal waters; use of chemicals and antibiotics; and the use of large amounts of wild fish for feed.
The increasing amount of the global commercial catch of small fish, such as anchovies and sardines, going to produce fish feed for farming of carnivorous fish species is becoming a serious sustainability issue. "Many people expect that aquaculture will relieve pressure on ocean fish populations, most of which are now already fished beyond capacity," stated Michael Weber, the report's author. "But it takes approximately three pounds of wild caught fish to produce just one pound of carnivorous fish. Clearly, this is not the way for aquaculture to feed the world."
SeaWeb's report warns that industrialized aquaculture is long overdue for reform and emphasizes that in their rush to pursue commercial production of other carnivorous species, corporations and governments must learn from and avoid the impacts associated with the current state of salmon farming.
"A couple of decades ago, when modern aquaculture really began to take off, it seemed full of promise and was proclaimed as an environmentally benign way to grow healthy protein for an expanding world population," stated Bill Mott, Director of the SeaWeb Aquaculture Clearinghouse. "As this report suggests, that promise is not being fulfilled with many kinds of aquaculture, such as salmon farming. The industry's 'next wave' - farming the larger carnivorous fish species, the 'tigers of the sea' - is clearly following an unsustainable path."
The report recommends that the expansion of finfish farming be based on closed systems, with total containment of fish and recovery and reuse of wastes. Several examples of 'good aquaculture' practices are discussed, including farming vegetarian species, employing polyculture or integrated systems that recycle nutrients and minimize effluents, and using closed systems that eliminate farmed escapes and the transfer of parasites and disease to wild populations.
The release of SeaWeb's report complements several other ocean conservation reports recently released including the Pew Ocean Commission's "America's Living Oceans: Charting a Course for Sea Change" that calls on Congress and the Administration to make sweeping changes in U.S. ocean policy, including a moratorium on coastal fish farming. World Wildlife Fund, in conjunction with the Atlantic Salmon Federation, recently released a critical report, "Protecting Wild Salmon from Impacts of Atlantic Salmon Aquaculture: A Country-by-Country Progress Report" that gives failing grades to all farmed salmon producing countries in the Atlantic. Additionally, a recent article in the scientific journal Nature reports that the oceans have been depleted of almost 90 percent of the world's populations of highly prized carnivorous fish species such as tuna, cod, and halibut.
Meanwhile, many are looking to aquaculture to compensate for the depletion of these valuable fish species. "Aquaculture is necessary for the future, as long as it's conducted in an environmentally and socially responsible way," stated Bill Mott. "We urge governments to look more holistically at aquaculture and its effects on marine ecosystems before allowing the industry to expand."
SeaWeb, headquartered in Washington, DC, promotes conservation of the ocean and the web of life it supports by raising awareness of the living ocean and its fragile state. Since 1998, the SeaWeb Aquaculture Clearinghouse has been raising awareness of the environmental and social issues related to aquaculture and generating involvement from all stakeholders, including the public, in order to encourage its sustainable development. We strive to maintain and promote healthy and productive coastal waters and watersheds through development of responsible aquaculture. The Clearinghouse is located in Providence, RI.
About the author
Michael Weber is a research consultant who has specialized in marine and coastal conservation for more than two decades. From 1980 to 1990, he directed programs on marine protected areas, sea turtle conservation, and marine fisheries at the Center for Marine Conservation and from 1990 to 1994, he served as a special assistant to the Director of the National Marine Fisheries Service.
The full report, including an executive summary, is available in PDF at: http://www.