The first questions addressed in this final Chapter relate to the opportunities and major constraints facing the continued development of intensive livestock and fish production. The factors stimulating these trends are examined and critically analyzed and the case made for novel or renewed closer integration. The relative opportunities for livestock waste use through aquaculture are then examined and contrasted with alternatives such as their value for crop production and energy generation. Trends in food consumption and water use are reexamined, and opportunities and threats to integrated livestock-fish production considered.
Opportunities for aquaculture and livestock within nutrient-poor, small-holder systems are then reviewed given our analysis in earlier Chapters and new approaches to multipurpose water use.
Global trading networks are increasingly challenging the concept of self-sufficiency and consumption norms. Much of the increase in demand for livestock and fish products is expected in LDCs, both in rural and urban areas. Although rural communities in LDCs are expected to grow further before stabilizing, full-time farming in many agro-environments is likely to decline. Demand for both livestock and fish products can therefore be expected to increase in rural as well as in urban and periurban environments where demand will climb even more swiftly.
Applying conventional sources of feeds and production systems is expected to allow response to these demands in the short-term, largely through increases in grain and protein feed crops in Brazil and the USA and a few other food surplus countries. In the medium-term, growth in demand may stagnate in countries with limited reserves of foreign currency, large populations and small capacity to increase crop production further. Countries such as Japan, Korea and Malaysia that import large quantities of feedstuffs will be particularly sensitive to global shortfalls in livestock feed ingredients (Farrell, 1996).
Commercial livestock production will increasingly be drawn to areas of relative advantage, especially those for processed products, often to areas within reach of ports for shipments of feed, or close to the areas where the feed is produced. Stringent environmental regulations and shortages of high quality water, in contrast, will also restrict intensive aquaculture. This will draw international investors towards less-densely populated regions and could impact relatively severely on the natural environment.
The major single limiting factor to increased livestock and fish production will be availability of feed. Competition for feed occurs at both the local level, usually for grain by-products such as brans and oil cakes, as well as the national and international level for concentrates of cereals, pulses and animal products (fish and meat meals). Fish meals and oils, being dependent on wild stocks, are particularly limiting for feedlot livestock and feedlot fish, particularly salmonids in colder countries and shrimp in the tropics.
Increases in the real price of concentrates are expected as globalization of world trade occurs, wild fish-based products become relatively scarcer and demand for livestock products soar in industrializing parts of the world. This will favour the most efficient users of concentrates in both livestock and fish production sectors and substitution of high cost ingredients; indeed the percentage of fishmeal in livestock feeds has fallen markedly in recent years.
Estimating the quantity of feed ingredients required in the future depends on how many animals are housed intensively, and how many remain extensively managed (Farrell, 1996). Currently a large proportion of livestock are raised extensively in developing countries although the overall trend is rapidly towards intensification.
Improving feed efficiency is a major challenge to animal and fish nutritionists, particularly for intensively raised monogastric livestock and fish. Increased feeding efficiency has already allowed the amount of livestock production to increase faster than demand for concentrates over the last decade. If the productivity gap can be closed between OECD countries and China, and other developing countries with rapidly growing demand for pig and poultry products, greater production can be expected without large increases in demand for concentrates (de Haan et al., 1997).
Broader definitions of efficiency may be more relevant in the future. Feeding efficiency, which is typically expressed as a FCR, gives little information on the quality of the feed or how feed is used within a broader farming system. Scavenging animals fed a supplementary feed produced on-farm, usually grains or grain products, will have poorer conventional conversion efficiencies than intensively-raised animals fed compounded diets. Wastes derived will also generally be of lower value for aquaculture. However cash outlays may be negligible and farmers, by using low cost grains in this way, add value to their farming output in an ‘efficient’ manner. The prospects for more use of concentrates and role of ‘improved’ strains by small-holders is considered later.
Grains and grain products are also the largest component of compounded livestock feeds, accounting for 70,75 and 65 percent of modern pig, broiler and layer diets, respectively (Farrell, 1996). Concentrates, typically comprising soybean and fish meals together with a range of higher cost additives (vitamins and minerals) is added to meet the exacting nutritional needs of breeds selected for their performance on such feeds. Feed conversion efficiencies are high but many factors, such as access to concentrates and markets and pricing of inputs and products, limit small-holder involvement.
The overall efficiency of both traditional and modern feeds and strains can be improved through their integration with fish. If overall production per tonne of feed is considered, integration can be seen to dramatically improve overall efficiency. Similar gains are possible when feedlot fish culture is integrated with semi-intensive culture of carps and tilapias.
Development away from conventional, grainbased livestock and fish production systems has been identified as a need for the humid and sub-humid tropics where cereal deficits are common. Alternatives include greater use of feeds traditionally used in some areas e.g. sweet potato and cassava, and development of unconventional feeds e.g. sugar cane, green pulse fodders, sugar palm (Preston, 1990).
Sustainable recycling of wastes produced by industrial livestock systems must be attractive, both financially and environmentally. Integration of aquaculture into such systems can be attractive; current linkages between better-off peri-urban livestock farmers, with little land and a lot of waste, selling waste to farmers specializing on horticulture or fish, already exist in parts of Asia. Good infrastructure (especially roads) and an enabling environment for the trading of inputs, products and by-products are necessary to make such options viable.
The relatively high value of nutrients and few technical alternatives for waste disposal have probably encouraged the development of these systems where they are important. However, in many areas of high livestock concentration, nutrient surpluses are often common. Recyling on the limited land areas within easy reach of producers can result in excessive loading, leaching and pollution of surface water. High water content of livestock wastes and transport costs limit the distances to which they can be used. Mineral fertilizers are often cheaper and easier to use.
The factors that have encouraged livestock production to become concentrated need policy changes to stimulate more rationale use of livestock wastes (Box 9.A). Improved overall efficiency of food production should be the aim, with an emphasis on reducing waste outputs of the whole system. The growth of industrial systems has been greatly stimulated by policy distortions in Western Europe, exacerbating the relative advantage of livestock producers that concentrate in the Netherlands, Brittany and other areas of Northwest Europe. In Singapore, the negative impacts of concentrated, intensive pig production has led to its abandonment (Box 9.B). These incentives may be unaffordable in developing countries, but poorer infrastructure and access to markets encourage livestock producers to concentrate in peri-urban areas resulting in similar concentrations of livestock operations and negative impacts. The same phenomenon has occurred in intensive aquaculture where the carrying capacity of the local environment has been exceeded such as the sites of intensive cage culture in reservoirs in West Java. The relative sensitivity of most cultured aquatic animals to changes in their environment may be an important factor in self-regulation but often not before long-term environmental and social damage has occurred. A range of measures may be useful to intensify livestock and fish production (Table 9.1) without spatial concentration.
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BOX 9.A Possible policies to discourage concentration of intensive livestock and fish production
|
TABLE 9.1
Measures to intensify livestock and fish production without spatial concentration
|
Problem |
Appropriate measures |
Impacts |
|
Increased urban demand leads to concentration and rural intensification of livestock production |
|
|
| |
|
|
|
In areas of high livestock-fish densities, high pollution poor, occurs |
|
|
|
Concentration of livestock/aquaculture due to availability of feed |
|
|
|
Concentration of livestock/aquaculture due to restricted access to markets |
|
|
|
Technology developed for industrial production only |
|
|
|
Dichotomy of industrial and back-yard systems |
|
|
Many forces are stimulating more technically advanced integration of food production. Increasingly, both public opinion and safety, concern for animal welfare and zero pollution must be satisfied. In the western world, pollution prevention and alleviation will drive both public and private investment in food production into the foreseeable future and zero pollution will become the target. In land-rich, warmer countries lower technology solutions will continue to develop, subject to stricter adherence to safety issues. Global trade will increasingly reduce the current differentials between hygiene requirements in LDCs and the developed countries and, meeting the media-fueled, consumer expectations will be critical to development of sustainable food production of all types.
In developed countries, biological processes have in some cases been superseded by use of industrial processes but the support costs may not be sustainable in the long term. Increasingly a return to, or combination with, microbial, fungal or invertebrate treatment processes for wastes, or as part of the production process, look likely.
The development of export-led livestock production, in which processed by-products remain in-country and are used to support fish culture, has obvious merits. This practice leads to efficient recycling of wastes at source, both production and processing, whilst generating high-value, low-cost animal protein in addition to foreign revenue.
Geographical range
Using fish culture as a component of broader food production systems has most potential in the tropics where temperatures remain elevated and stable year-round. However, wastes have been used traditionally for aquatic production in both the sub-tropics and temperate zones. The lower temperature regimes of tropical highland areas such as Rwanda, are also known to reduce aquatic productivity (Molnar et al., 1996).
Trends in land and environmental planning suggest opportunities exist for aquaculture to be more central to waste disposal in the future. Variations in ambient temperatures through the year is an important design criterion for biological waste treatment of any type. The residence times of wastewater passing through stabilization pond systems in temperate zones are based on changes in seasonal efficiency. Poorly designed systems result in seasonal overloading and fish die-off, such as occurred in poultry-fish systems in Hong Kong (Sin, 1980). Integration of large pig production units and fish culture has occurred in Hungary and treatment of wastewater has been traditional in Europe and subtropical parts of Asia (Edwards, 1992). Ensuring optimal loading rates of organic waste, be they of animal or human origin, may require pre-treatment and storage capacity in most cases to ensure wastes are used efficiently.
The use of livestock wastes must be viewed within the context of further increases in organic waste production of all types and the likelihood of more stringent control of dumping, land fill and other methods of disposal. An increased role for artificial wetlands within urban and periurban landscapes would enhance flood control, wildlife conservation and wastewaster treatment. Integration of fish production is a traditional feature of such systems in some Asian cities. Incorporation of aquaculture within broader water and wastewater treatment and storage has become a major part of Israeli settlement patterns where water conservation has made the use of wastewater for secondary irrigation a necessity.
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BOX 9.B Singapore phases out pig production
Source: Taiganides (1992) |
Use of animal wastes for other purposes
The major problem of animal waste disposal has stimulated research and development in developed countries towards alternative methods. Recycling by spreading on arable land has many constraints and has resulted in significant damage to groundwater resources and natural aquatic and wetland ecosystems. Odour and the leaching of nitrates and other pollutants into groundwater has spurred legislation in Europe and in Singapore hastened the phasing out of intensive livestock production (Box 9.B).
A major problem is the sheer concentration of animal wastes, typically collected and stored as slurry, which is expensive to transport and treat. Most strategies require considerable energy to dry the waste. Separation and composting of manure solids and its use for high value horticultural container medium is possible (Inbar et al.,1993) but given the amounts have limited impact (Box 9.C).
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BOX 9.C Separation of solid and liquid waste fractions improves the efficiency of livestock waste use in farming systems
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On-site processing (drying, composting and fermentation) are options but are unlikely to be cost effective if low value soil conditioners alone are produced. However, the use of fresh manure to produce live feeds, primarily for fish and also a lowmoisture, compost-like material for horticultural use has proved commercially viable (Nuov et al., 1995). Farm mortalities and processing wastes are other major by-products of intensive livestock production that have often been disposed of in landfills or incineration, although local composting has been recom- mended by some. Rendering to meat meals has been a conventional approach for such products but is now subject to criticism by both consumers and legislators following the BSE crisis. Re-feeding of poultry litter and other wastes has been a standard practice in some areas (Chapman, 1994).
Marketability of fish produced in livestockfish systems
The trend for rising fish consumption in industrial economies, especially in countries with traditionally low consumption, is gaining momentum. Increasing affluence and the demonstrated health benefits of eating fish regularly appear to be important underlying reasons for this trend. The health benefits of polyunsaturated fatty acids contained in temperate, usually marine fish have also now been shown to occur in warm water carps (Steffens and Wirth, 1997).
The ecological benefits of eating such fish feeding low in the food chain rather than carnivorous species have yet to become a major marketing angle, but will undoubtedly become an issue. Currently, those marketing farmed fish make association with natural fish stocks and pristine environments. A key relative advantage of fish is that it is one of the few foods still available from natural environments; those marketing fish focus on the ‘clean’ and ‘natural’ credentials of their product. Sites are identified for their unpolluted nature, even though intensive aquaculture typically results in significant declines in downstream water quality. There are dangers, therefore, in any association of farmed fish with ‘waste’ of any type, especially in the light of increased consumer sensitivity to food scares in developed countries. Practically, a period of intensive fattening of waste-fed fish in a separate system should satisfy the need for ensuring consistent quality and for distancing the waste and the product eaten by the consumer. Another approach is to process fresh wastes through intermediate live feed organisms before feeding to fish consumed by people (Edwards, 1990). Using unprocessed livestock waste to produce fish up until the time of marketing may be unacceptable for consumers unaware of the realities of food production generally. Ironically, the rapid rise in demand for ‘organic’ products in industrialized countries may signal a change in attitudes from which fish farmed in organically fertilized, aquatic pastures may benefit.
Clearly, if waste-fed fish are to be acceptable to sophisticated urban consumers, a range of efforts will be required. HACCP principles need to be applied to reduce risks of pathogen transfer at all stages of production and processing. Different approaches to lengthening the food chain, rigorous monitoring of quality and a focus on the ‘organic’ qualities of fish produced will all support marketing of fish produced in this way.
A variety of factors affect opportunities for more integration of livestock and aquaculture in rural areas of developing countries. These relate to demography, as predominately rural societies urbanize and change their expectations and the nature of demand for food. Policies that promote livestock and aquaculture, especially with regard to the importation, production and marketing of feeds and breeds, are critical. Intensification of small-holders’ livestock through developing alternative feeding strategies based on locallyproduced and purchased feeds, is also considered.
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BOX 9.D Changing opportunities for smallholders to integrate egg-duck and fish production Improved infrastructure, particularly road networks and availability of feed concentrates, has improved markedly over the last two decades in rural Northeast Thailand. This has raised opportunities for small-holders to intensify both livestock and fish production. Previous attempts to promote duck egg production integrated with backyard fish production had failed for a variety of reasons (Box 7.Q). A recent Department of Fisheries initiative to promote egg-duck integration with community fish production appeared to have potential as duck egg production was now viable even in remote areas. However, in practice small-scale production integrated with individually owned, or community fishponds, remained constrained by a variety of factors. Labour constraints forced holding the ducks around the homestead rather than over the water body and encouraged flocks to become larger. Wealthier people, usually women who could afford the regular cash investment, tended to specialize in duck egg production. Government programs purchasing duck eggs for children’s school meals stimulated regular demand in the village but competition with cheaper chicken eggs distributed through networks of middlemen reduced profit margins. Many of these eggs were derived from layer operations, usually located in irrigated areas of the region, which were integrated with pond fish culture (Engle and Skladany, 1992). |
The availability of nutrients in rural areas is a major constraint to productivities of both terrestrial and aquatic systems. The role of extensive production methods for nutrient-poor situations is considered. A further issue of importance is the role of on-farm irrigation in agricultural development and how ponds deliver most benefits as a multipurpose resource.
Changing Demography and demand
Rural migration, while reducing labour for raising livestock and fish, also reduces demand for small-scale, locally produced livestock and fish. This can be compounded if improved roads and other infrastructure favours import of low-cost competing products into rural areas, further undermining demand for locally produced food. There is a tendency for large producers to squeeze small farmers in this way despite local poultry being considered superior to intensively farmed birds in most of Asia. Improved infrastructure can, however, allow import of productivity-enhancing inputs and access to urban markets (Box 9.D). This is particularly important as the agricultural work force ages and labour efficiency becomes critical for innovations to be sustained. Government policy to encourage rural livelihood options that include diversified agricultural, service and industrial development is required.
Intensification using modern breeds and feeds
Modern breeds require balanced, high-value nutrition that can be produced with strategic imports even in resource-poor areas. If concentrates appropriate for blending with local grains and byproducts are available, small holders can produce pigs and poultry very efficiently and benefit from the valuable nutrients for fish culture. One analysis in Northeast Thailand indicated that use of concentrates to complement local rice bran and cassava as a pig feed could increase herd size by a factor of 8 and the amount of fish by ten (Little and Satapornvanit, 1996). Government policy to actively encourage agribusiness to focus on the needs of small-holders by improving the availability to them of modern strains, feeds and veterinary services to them in rural areas is required. Decentralized livestock production and marketing will also benefit local consumers and service providers.
Alternative approaches to intensification-novel feed and traditional breeds
In some situations local breeds and feeds have been found superior to those introduced. Often a hybrid approach, in which local and introduced strains are hybridized and local feeds supplemented with improved varieties and inputs, is required on a practical level.
Understanding the nature of constraining factors is also important. A lack of dietary energy, rather than protein, has been found to limit the productivity of scavenging poultry and can best be improved through use of locally available supplements (Men, 1996). In contrast, protein is a major constraint to increasing productivity of penned local and hybrid pigs in Viet Nam. Low input strategies for monogastrics make use of both a natural ability to scavenge and omnivorous tendencies. Pigs utilize microorganisms in the caecum and colon to digest materials unhydrolysed in the stomach and small intestine (Livingstone and Fowler, 1984). Diets of breeding animals can include a high proportion of bulky feeds if complemented by small amounts of cereal/concentrates. Conversion efficiencies of traditional strains of animals on low-input systems are poorer than modern breeds fed formulated rations, but environmental impacts and support costs are lower. When feeds are not given, or given in small quantities, such measures are not meaningful and ‘efficiency’ needs to be reassessed (Box 9.E). Very significant improvements in productivity can be attained using strategic feeding of locally available supplementary feeds to traditional varieties of scavenging poultry (Box 9.F).
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BOX 9.E Assessing efficiency of traditional, upgraded and modern livestock systems Levels of input as well as output determine the efficency of production, by definition. Whereas the energy requirement of an intensively-reared White Leghorn is 300-320 kcal ME. bird-1 day-1, a smaller native scavenging bird requires a minimum of 286 kcal ME. bird-1 day-1, although lower levels of egg production are supported. But, if under an intensive system 240 eggs. bird-1 can be produced but the total cost of inputs equals 220 eggs, the net production is only 20 eggs. Bird-1. In a scavenging system around 40 eggs. Bird-1 can be produced without any additional feed costs, representing a net production of 40 eggs. Bird-1. Supplements used strategically may improve on this level of efficiency.
Concentrates that increased protein up to 100g protein. pig-1 day-1 increased live weight gain, cost effectively, by 83 percent (Nguyen, 1996). Even small amounts of commercially produced concentrates are often unavailable or prohibitively expensive in rural locations, however. Small fish regularly harvested as a by-product from a pond receiving livestock and other wastes could be used as a strategic feed supplement to enhance the productivity of livestock (Box 9.F). Alternatively, seasonal surpluses of wild and culture fish can be sun-dried or fermented for use throughout the year. The nutritional value of such approaches has been confirmed by trials in which waste-fed tilapia were tested as carnivorous fish and livestock feeds. The practice of using the fish pond as a feed source for penned livestock is already common in Northern Viet Nam where aquatic weeds are harvested and fed to pigs. The main issue is the likelihood that even small fish have a higher value for direct human food than the extra benefits to pig production from using them as a supplement. A simple analysis suggests that this strategy is unlikely to be attractive except where fish have low value. |
Extensification - use periphyton
Chronic under-fertilization of ponds is a major problem in resource-poor farms throughout LDCs. Lack of knowledge of the possible benefits, or a wish to avoid eutrophication of stored water for a variety of purposes, may explain this ‘mismanagement’. More often a lack of available nutrients means that production is sub-optimal. Where land holdings and ponds are small and agriculture is intensive, efforts should be made to optimize plankton-based fish production often using inorganic fertilizer. In situations where ponds are larger and nutrient requirements to optimize autotrophic-based production are high, more strategic use of nutrients may be advisable. Research in Bangladesh has found that substrates placed in relatively infertile ponds to increase periphyton can almost double production of fish (Wahab et al., 1999). A long established tradition in West Africa of using substrate to attract wild fish evolved into acajada systems in which periphyton growing on the substrate also becomes a food source for stocked fish.
A constraint to the wider adoption of these systems is the opportunity cost of suitable biomass. Wood and woody waste are in demand for fuel and other purposes in most LDCs. Intensification of ruminant livestock that involves growing leguminous multipurpose trees for fodder and fuel as borders, or on marginal land, is one strategy to increase both the availability of woody substrate and quality livestock feed.
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BOX 9.F Feeding pigs on small fish Assume: one pig raised from weaner to finisher over 150 days requires an extra 100 g protein. pig-1 day-1 to improve productivity and returns1. Assume: fresh, small-sized tilapia contain 62 percent crude protein on a DM basis, fresh tilapia are 76.8 percent moisture. Then, 696 g fresh fish. day-1 are required, or 105 kg over 150 days. The size of pond required to produce this amount would depend on the yield Fresh fish produced (kg) to support a 150 day pig production cycle in ponds of different sizes and yields. |
|||||||
|
Fish Yield (t ha-1 y-1) |
Pond Area (ha) |
||||||
| |
0.01 |
0.02 |
0.05 |
0.1 |
0.15 |
0.2 |
0.3 |
|
0.5 |
2 |
4 |
10 |
20 |
30 |
40 |
60 |
|
1.0 |
4 |
8 |
20 |
40 |
60 |
80 |
120 |
|
1.5 |
6 |
12 |
30 |
60 |
90 |
120 |
180 |
|
2.0 |
8 |
16 |
40 |
80 |
120 |
160 |
240 |
|
2.5 |
10 |
20 |
50 |
100 |
150 |
200 |
300 |
|
3.0 |
12 |
24 |
60 |
120 |
180 |
240 |
360 |
|
3.5 |
14 |
28 |
80 |
140 |
220 |
280 |
420 |
|
4.0 |
16 |
32 |
100 |
160 |
260 |
320 |
480 |
Source: 1Nguyen (1996)
A further linkage between periphyton-based systems and livestock would be to soak substrate in livestock urine to increase periphyton growth and, subsequently, fish production.
Water resources
The universal value of perennial water on-farm to enhance productivity and reduce drought- and flood-related loss has been greatly underestimated by institutions promoting fish culture. Water bodies, both community and household, have traditionally served a variety of functions in rural areas including livestock and fish production (Table 9.2). Maintaining or enhancing the multiple uses of water bodies may be the cornerstone of wider adoption of fish production by poorer people. Water bodies, whether ponds, weirs or small dams within watersheds, have important roles in nutrient conservation and concentration in addition to their primary function of water storage for downstream irrigation.
Irrigation of high-value vegetable and fruit crops planted around perennial ponds, and as successive plantings in the exposed sediments of seasonal ponds, have been shown to have greater impacts on household food security and income than the fish produced. In a range of models of pond-based fish and vegetable production in Ghana, fish yielded only between 1-2 percent of on-farm income (Prein and Ofori, 1996). Unsurprisingly farmers, especially women responsible for both production and marketing of such ‘homestead’ crops, often concentrate resources for vegetable production rather than optimising outputs of fish.
FIGURE 25
Schema of the major interactions between the various subsystems in a crop/livestock-fish integrated farming system
Source: Edwards (1993)
The relative size of the pond given the overall land holding, suitable conditions for pond construction, and availability of inputs (and fish yields), interact to determine the optimum for any given conditions. In Northeast Thailand construction of ponds to alleviate water shortages in rainfed areas has been widely promoted through subsidised construction and extension. Linear programming has been used to investigate optimal resource use and it was found that earthen ponds of 1 000 m2 can produce over 20 percent of farm income on mixed farms in which vegetables, rice and cassava are the other main crops (Setboonsarng and Edwards, 1998).
TABLE 9.2
Aspects of multipurpose use of a water body involving livestock and fish production
|
Feature |
Constraints |
Management |
|
Source of drinking water for fish and livestock |
|
|
|
Large livestock wallowing in pond |
|
|
|
Water birds swimming |
|
|
|
Source of feed for fish and livestock e.g. small fish, snails and shrimp |
|
|
|
Source of water weeds for fish and livestock |
|
|
Trends in food production and consumption within Asia point to large inequalities between and within countries. High-income countries in East and Southeast Asia are consuming more meat and fish in absolute terms and as a proportion of the total diet than before. In contrast, rural livelihoods in poorer countries, particularly among marginalized people, may be deteriorating in terms of diet and overall welfare. Whereas smallscale farms in South and Southeast Asia raising livestock and fish are typically crop-dominated and nutrient-poor, ‘industrial’ commercial livestock farms are nutrient-rich and may have significant environmental impacts if wastes are not recycled. Traditional livestock systems may not produce wastes in either enough quantity or of suitable quality to sustain current grain crops. The use of these wastes for aquaculture may therefore have negative impacts elsewhere in the farming systems. In contrast, modern systems tend to be concentrated in peri-urban areas where use of wastes to fertilize either field crops or fishponds is impractical.
Under certain conditions a fishpond could become the focus for diversification of small-scale farms in developing countries. Ponds in which fish are stocked can be used for the strategic irrigation of both crops and livestock. Integrated water use for agricultural and domestic purposes is often the primary incentive for incorporation of fish culture on-farm. The purposeful production of crops for feeding to fish directly, or to livestock, and livestock manure being used as pond inputs has shown potential (Figure 25).
However, several factors may hamper synergism between crops, livestock and fish. In areas with the greatest need for integrated farming, rural overpopulation may have led to land holding fragmentation, constraining the physical integration of livestock and crop production near the pond. Industrialization and migration can make the opportunity costs of growing on-farm feeds, raising livestock and/or using wastes less attractive. Fish may also compete with livestock for certain feeds, particularly valuable crop by-products. Some degree of intensification of livestock may be necessary to make their production viable and their wastes more valuable and available for fish culture. Inorganic fertilizers can be profitably used to ‘spare’ limited amounts of animal manure, especially when live or fresh fish can be marketed locally at high prices. A judicious mix of traditional and introduced inputs may often be the most practical approach.
Rapid economic development in the Asia Pacific over the last two decades has been a major stimulus to the dynamic growth of livestock and fish production in the region. The rise of agroindustry and its role in the introduction of modern strains and feeds have been particularly important. Demand and use of formulated, balanced diets has grown rapidly, particularly for pigs and poultry, and to a more limited extent for cattle. Pingali (1995) explains this is a natural result of increasing demand, rising labour and declining transport costs. Where feed industries are established, predicting the development of feed-based or waste-based aquaculture also becomes a major issue (Figure 26).
The major challenges are to assess the role of livestock-fish integration to improve both the livelihoods of small-scale, rural households and to make cultured freshwater fish affordable for poor urban consumers.
FIGURE 26
What factors stimulate feed or waste-based aquaculture?
