Agricultural Pollution Aquaculture Why Care about Aquaculture Pollution? Figure 1: Tilapia Farm in China Global fisheries production has risen rapidly over the past 60 years at over two and a half times the rate of world population growth, and aquaculture today is among the fastest-growing food sectors. The rapid growth in fisheries products, and the rise in aquacul- ture in particular, enabled per capita fish consumption to nearly double globally between the 1960s and 2010, and more than triple in developing countries (see fig- ures 2 and 3). While fisheries worldwide, like other agricultural systems, have long been affected by water pollution, the sector’s rapid growth and intensification are increasingly contributing to that problem. This is not only damaging to aquatic ecosystems and water users at large, but also harmful to the fishing industry itself. A historic opportunity presents itself to tackle aquaculture pollution in step with industry growth, and to shape a more sustainable source of animal protein as demand for it grows. Source: © Unitedstill.com Nature and Magnitude of the Problem growth witnessed over the past 25 years is attributed to Aquaculture is by far the larger polluter within the fish- the development of aquaculture in China, where domes- eries sector, even though certain capture fishery practic- tic demand grew by around 6 percent per year between es—such as the dumping of organic wastes into marine 1990 and 2010. Today, China is the largest aquaculture environments—can be a cause for concern (see box 1). In- producer by far (see figure 4). deed aquaculture, like land-based livestock rearing, gen- Going forward, continued growth in aquaculture erates spatially concentrated wastes that, if improperly products is likely given rising demand for animal managed, can result in significant water pollution prob- products and seafood appreciation among the swelling lems.1 Animal feces in particular give rise to a concentrate middle classes of urbanizing, emerging economies—in of nutrients, pathogens, suspended solids, and substanc- Asia particularly—and the finite potential of capture es such as heavy metals, hormones, anesthetics (used to fisheries. Meanwhile, competition for land and fishery mitigate animal stress), antibiotics, and antimicrobials resources needed to sustain aquaculture is likely to con- that are fed as supplements to animals. Other substances tribute to shaping the aquaculture sector, possibly driv- found in aquaculture waters include unutilized feed and ing it to develop in marine settings. drugs, fertilizers, discarded plant and animal residues (offal), piscicides and molluscicides, and chemical addi- Impacts tives such as stabilizers, pigments, antifoulant paints, Depending on how they are handled, aquaculture salts, and disinfectants (for example, chlorine). wastes—especially when they are concentrated—can fer- While aquaculture and capture fisheries contributed tilize bodies of water leading to eutrophication, toxicity, in roughly equal proportion to global fisheries output and hypoxia. They can disrupt ecosystems through tem- in 2013, aquaculture was on a starkly different growth perature change, cloud surface waters, taint drinking wa- trajectory. Indeed, aquaculture has been increasing at ter, provoke chronic and acute diseases, and contribute to a near-exponential pace since the 1960s, whereas cap- antibiotics resistance. In aquaculture systems themselves, ture fishing started to level off in the 1990s. Much of the inadequately managed wastes can undermine produc- 1 Other ecological impacts not covered here include the destruction of mangrove forests and other natural ecosystems as a result of their conversion to fish ponds; pollution from the production of feed crops; and pressure on wild fish populations to the extent that these are also fed to farmed species (aquaculture accounts for well over half of global demand for fishmeal). This note was written by Emilie Cassou. Full references and acknowledgments are available online. Agricultural Pollution Aquaculture Figure 2: Global Fisheries Production, Figure 3: Fisheries Production in Developed and 1950–2013 Developing Countries, 2003 and 2012 Millions of tons Millions of tons of product 200 200 150 150 100 100 50 50 Developed Developing Developed Developing 1950 1960 1970 1980 1990 2000 2010 2003 2013 ■ Capture ■ Aquaculture (Stacked) ■ Capture ■ Aquaculture Source: Based on the Food and Agriculture Organization, Fisheries Global Information System data. Note: Total fisheries output in 2013 was over 191 million metric tons. That year, aquaculture output overtook that of capture fisheries for the first time. tivity, food safety, and profitability. They can also leach concerns about genetic pollution beyond national bor- into and salinize agricultural soils, reducing farmland ders despite its high feed-conversion efficiency. productivity. Bans on imports of chemical-contaminated While the largest aquaculture facilities tend to be shrimp have come at a great cost to China’s aquaculture subject to environmental regulations, these are imper- industry, for example. And for all the chemicals used to fectly enforced; and the bulk of global aquaculture pro- fight infection, one third to half of farmed fish and shrimp duction occurs in semi-intensively managed ponds that are lost due to poor health management before they can are not subject to or escape rigorous oversight. These, be marketed, according to a 2006 estimate. moreover, often have limited capacity to invest in or In parallel, aquaculture can be a source of biological absorb abatement technologies. Polluting practices also pollution. This results when escaped farmed species stem from producers’ partial awareness of the impacts interbreed with, outcompete, or transmit parasites and of their practices, or a lack of near-term economic incen- diseases to wild species.2 Interbreeding can reduce wild tives to modify these. species’ life-span and disease resistance, disrupt their natural life cycle, slow their growth, and even reduce Drivers their edible portion in some cases. The recent approv- In absolute terms, aquaculture pollution is being driven al by U.S. regulators of a fast-growing, genetically en- by the broad changes that are leading to the subsector’s gineered salmon (see figure 5), for example, has raised rapid growth and intensification. Factors include in- Box 1: Making Sense of the Fishery Sector: Aquaculture versus Capture Fisheries Aquaculture refers to the farming forth. It also implies individual or occur naturally in marine or freshwater of aquatic organisms including fish, corporate ownership of the stock environments and are exploitable mollusks, crustaceans, and aquatic being cultivated during its rearing by the public as a common property plants in either marine or freshwater period. Aquaculture can take place resource—with or without appropriate environments. Farming implies some in many settings, including in ponds, licenses. Capture fisheries are form of intervention in the rearing lakes, rivers, reservoirs, tanks, rice generally either industrial, small-scale/ process to enhance production, paddies, and the ocean (in cages). artisanal, or recreational. (Based on such as regular stocking, feeding, Capture fishing, by contrast, is the United Nations Food and Agriculture protection from predators, and so harvesting of aquatic organisms that Organization definitions.) 2 The introduction of uncommon species can also attract predators. Agricultural Pollution Aquaculture Figure 4: Aquaculture Production of Aquatic Animals for Human Consumption, 2011 Metric tons ■ No Data ■ 0–100 tons ■ 101–1,000 tons ■ 1,001–5,000 tons ■ 5,001–200,000 tons ■ 200,001–1,000,000 tons ■ 1,000,001–5,000,000 tons ■ >30,000,000 tons Source: FAO Fishery and Aquaculture Statistics. Note: Production of aquatic plants not shown. creasing demand for animal protein, the overexploita- technologies, without having to devote extensive time tion of wild fishery resources, and increasing scarcity of and resources to research and development pertaining land, labor, and other resources. In Vietnam, increasing to native species. Where regulatory frameworks are saline water intrusion linked to sea level rise and sub- weak or inadequately enforced, the development of new sidence in the Mekong River Delta has, for instance, led aquaculture operations and how these are run are often growing numbers of rice farmers to grow shrimp, which divorced from an understanding of ecosystems’ carry- are both more salt-tolerant and in demand. ing capacity. A number of cases, meanwhile, point to the In more relative terms—recognizing the degree to potential for the environmental performance of highly which aquaculture pollution can vary from one system intensive systems to improve as they mature and are to another—aquaculture pollution is largely attribut- subject to increasingly strin- able to the lack of economic incentives for adopting or gent regulatory and mar- Figure 5: AquaBounty Salmon even developing more ecologically-friendly systems. ket demands. Both organic This partly reflects producers’ insulation from the so- waste and antibiotics use cial and environmental costs of pollution. It also reflects have declined in the Nor- their inability to obtain a higher market return on more wegian salmon industry, for sustainably produced products—whether due to mar- instance, even as production ket realities (for example, weak or fickle demand for has risen (see figure 6). higher quality), or to a lack of awareness, know-how, technology, product differentiation ability, or invest- What Can Be Done? Source: © AquaBounty Technologies. ment capacity. While market demand for greener aqua- Direct mitigation through Note: Size comparison of an AquAdvantage® Salmon (background) vs. culture products is developing, the market signal and changes in management a non-transgenic Atlantic salmon sibling regulatory demands on the industry in many parts of practices (feed, additive, (foreground) of the same age. Both fish the world have evidently driven limited environmental and effluent management). reach the same size at maturity but the awareness and investment on the part of producers. The Pollution from aquaculture non-transgenic salmon will take twice as result has been underinvestment in research on locally systems can be directly mit- long to grow to the mature size. adapted species and aquaculture management practic- igated through the adoption es, in traceability systems, and in industry coordination of alternate technologies and management practices, and technology dissemination. In the Philippines, for some involving the modification of system inputs, and example, aquaculture growth has centered in large part others, changes in the management of system outputs. on non-native fish species as this has allowed industry On the inputs side, for example, the use of nontradition- to import or replicate existing aquaculture models and al feed ingredients (for example, eubiotics) and drug Agricultural Pollution Aquaculture alternatives (for example, immunostimulants and nutra- ceuticals) can improve health and production while re- Figure 6: Norwegian Salmon Production and Antibiotics Use, ducing the need for chemicals and drugs typically used 1980–2014 in aquaculture. Kilograms LEGENDTK On the outputs side, effluent management practices 50,000 1,500 have significant bearing on water pollution, particularly in intensive systems that generate concentrated wastes. 40,000 1,200 Available mitigation options are highly site-specific and 30,000 900 depend a great deal on the dilution of effluent. In most cases, pond wastes are too dilute for conventional sewage 20,000 600 treatment technology. Where there is an abundance of ad- jacent land, aquaculture effluent can be used to “fertigate” 10,000 300 cropland, or be sent to constructed wetlands or settling ba- sins. The land intensity of these practices, however, limits 1980 1985 1990 1995 2000 2005 2010 their applicability, and in some cases, the use of effluent ■ Antibiotics ■ Production on cropland presents food safety concerns. Partitioned Source: Based on data from the Norwegian Directorate of Fisheries, provided aquaculture systems approach the problem by aiming for by Frank Asche. Permission required for reuse. zero discharge. These circulate tainted waters through treatment tanks and ponds, making use of phytoplankton and higher-order species that serve a filtering function. and species selection—though more accessible to new The more general practice of implicating multiple species operations than as retrofits to existing ones—can have in waste management is further discussed below (species significant ramifications for pollution and its impacts. selection). The fallowing of modern fish farms is a less Distancing aquaculture from sensitive ecosystems and technically demanding solution to effluent treatment, but dense population centers can be one way of reducing one that implies foregone revenues in exchange for lower harm. Conversely, the adjacency of cropland, vegetative upfront investment costs. Regardless of the approach, ef- buffers, or space for treatment ponds can open possibili- fective monitoring is generally required at both the farm ties for mitigation (as noted above). Certain aquatic envi- level and downstream—and is often a weak link—when it ronments, such as the deep sea, can have the advantage comes to effluent management. of diluting and flushing waste to a point of doing little Indirect mitigation through efficiency gains (breed- harm—provided that they are not proximate to sensitive ing). Mitigation can also be achieved indirectly, through marine ecosystems—but these are not always an option, actions that enable efficiency gains. For each gram of pro- limit species selection, and can present other drawbacks. tein, aquaculture products already tend to convert feed Certain species and varieties, mean- more efficiently, and emit less nitrogen and phosphorous, while, are inherently more resilient and Figure 7: White Shrimp than livestock products—notably beef and pork (whereas less demanding with regard to inputs poultry and milk are comparable to aquaculture). None- or waste management than others (for theless, there is room for improvements in aquaculture example, the white shrimp or P. vanna- productivity, some of which may be achieved through mei in figure 7). More transformational, further intensification, and others through changes in the production of multiple species— existing, intensive or semi-intensive systems. To the ex- aquatic or land-based—in a single, tent that many aquaculture operations are still relative- integrated system can be an attractive ly young, for example, the domestication and selective means to prevent pollution by convert- Source: © Seven Seas International breeding of aquatic organisms for feed conversion ef- ing one species’ waste into another’s USA ficiency, rapid growth, and disease resistance have the feed, thus giving it value. Far from potential to improve the environmental performance of new, this form of polyculture is already widespread— existing aquaculture systems over time. These consid- Asian rice growers have raised fish in paddies for cen- erations need to be balanced with concerns for genetic turies3 —but its practice has increasingly given way to pollution related to the release or escape of non-native or intensive monocultures able to produce higher volumes, invasive species in aquatic ecosystems (hence the geneti- with greater quality and consistence. Similarly, the use cally engineered salmon controversy). of livestock manure to fertilize ponds is a practice that Indirect mitigation through changes to sector is being abandoned as it can impart unwanted flavor on structure (site and species selection). Changes in site seafood. Growing interest in sustainable production, 3 When aquatic animals are farmed in conjunction with crops such as rice (directly in fields or in nearby, connected reservoirs or ponds), fish wastes help fertilizer rice crops, reducing the need for synthetic fertilizer and reducing nutrient pollution from fish fecal matter. When they are cultivated directly in rice paddies, certain aquatic species also play a pest management role, helping farmers reduce their reliance on synthetic pesticides. Agricultural Pollution Aquaculture however, has driven an increasing number of businesses (box 2) illustrates how the public sector can help industry to experiment with integrated systems that can meet the address its environmental impact in ways that improve demands of today’s consumers and tomorrow’s markets. its positioning in the market. In this example, the govern- Various trials have been conducted combining fish with ment acted not only as a regulator but also as an advocate, lower trophic-level species such as seaweeds, oysters, facilitator, and partner, and as a funder of research and and mussels. extension; and it mobilized the private sector by treating Indirect mitigation through the management of environmental challenges as being central to productivi- industry size and intensity. In the longer run, other ty, quality, food safety, and competitiveness. indirect mitigation strategies include curbing industry Many changes in aquaculture management practic- growth and certain aspects of intensification, though es—the treatment of effluent or the fallowing of ponds these need to carefully weigh the environmental trade- for example—impose costs on the sector, eating into offs they imply, with consideration for the environmental profit margins. Industry uptake thus often calls for more impacts of substitute products and production systems. robust and sustained intervention on the part of the Public sector role and instruments. Some of the public sector to modify aquaculture operators’ econom- above changes can pay for themselves through near- ic calculus by imposing and enforcing regulations, sub- term to midterm returns in efficiency, product quality sidizing improved practices, and taxing or fining bad (including safety), and market access, though they may ones. In the Philippines for example, the Government initially require a number of market-enabling invest- has established mariculture parks in selected coastal ar- ments, channeled through public-private partnerships. eas of the country with the intent to not only alleviate These can include investments in research and technol- pressure on capture fisheries and stimulate aquaculture ogy commercialization, awareness-raising and behavior employment opportunities, but also to develop areas change among both producers and consumers, and sys- with appropriate infrastructure and equipment and tems that enable product differentiation, risk monitoring, promote the use of environmentally friendly inputs and and traceability. The case of the Thai shrimp industry practices in a targeted way. Box 2: Managing the Environmental and Quality Risks of Intensification: Thai Aquaculture Aquaculture intensification has been high levels of compliance with international reshaped the industry. Industry concentration associated with such food safety and standards. The Thai Government has taken was one factor, as vertically integrated and environmental problems as disease outbreaks multiple steps in this period to improve contract-based operations more easily met in domesticated and wild stock, antibiotic industry practices. To address hygiene and certification requirements than independent residues, water salinization and pollution, safety, for example, it developed a good micro, small, and medium enterprises. biodiversity loss, and the depletion of aquaculture practice guide (GAP) and Another factor was the introduction of a wild resources. In the 1990s, Thailand’s voluntary certification program and took domesticated, disease-resistant variety of shrimp industry faced a looming crisis as measures to control and monitor antibiotic white shrimp (P. vannamei, see figure 7) international concern about the safety and use. The Government’s Q-Mark labeling that requires less antibiotic, water, and feed environmental impacts of Asian aquaculture program, introduced in 2004, gave producers than the previously dominant Thai black led to import restrictions and a tightening the opportunity to seek certification for shrimp. Other factors of success included of quality of standards. But whereas Taiwan, meeting a code of conduct (CoC) that went the Government’s commitment to industry China saw its shrimp industry collapse in the beyond GAP in addressing environmental participation in standard development and 1990s, Thailand raised its reputation as a management and traceability. The CoC program design, and its investments in reliable source of quality and safe shrimp in incorporated multiple international standards industry capacity for monitoring, surveillance international markets. and guidance developed by Codex, the and testing, and hence compliance. Lead Proactive government involvement in International Standards Organization (ISO) firms and farmer clubs also played a role in the development and implementation of and the FAO. diffusing improved management practices by both public and private quality certification Several factors helped businesses disseminating knowledge and innovations. programs has, over the past 15 years, conform to GAP, the CoC, and a host of allowed the Thai shrimp industry to achieve private voluntary standards that have