This review of integrated livestock-fish farming describes the rationale of integrated farming and reviews the different integrated livestock-fish farming systems as they are practised in different countries. The future development of livestock-fish production is also discussed and future research needs are identified.
Integrated farming of fish and livestock is an old practice consisting of the culture of fish (or shrimp) associated with the husbandry of domesticated animals such as pigs, ducks, chicken, etc.
Integrated farming is traditional in Asia, especially in China and is now also applied in Europe and, on a small scale, in Africa and some Latin American countries.
In many developed countries, intensive-scale aquaculture is now considered as a source of pollution of the environment due to the release of organic matter into the rivers. This is particularly the case of trout farms. Intensive farming of pigs and poultry produce large quantities of manure and animal wastewaters which must now be treated in order to prevent serious environmental problems.
The most prevalent method of manure disposal is its use as fertilizer on land, but excessive use of fertilizers will lead to eutrophication of inland and coastal waters.
There is a possibility of recycling organic wastes, manures and farm effluents in fish ponds. The end product is an improved production of animal protein, particularly needed in developing countries.
The aim of integrated farming is the recycling of animal wastes (faeces, urine and spoiled feeds) to serve as fertilizers, and sometimes as food for fish raised in ponds, enclosures and cages. According to Olah (1986; cited in Billard et al., 1990), the amount of organic matter which can be recycled in ponds as fertilizers is up to 5g C.m2d-1, corresponding to 100 kg of dry manure ha-1 d-1 and the expected production in polyculture (common carp and silver carp) may reach 30 kg ha-1 d-1 without feeding the fish. Such a yield is much higher than classical animal production on land.
According to Pillay (1990), the basic principles involved in integrated farming are the utilization of the synergetic effects of inter-related farm activities, and the conservation, including the full utilization, of farm wastes. It is based on the concept that “there is no waste”, and “waste is only a misplaced resource which can become a valuable material for another product” (FAO, 1977).
RATIONALE OF INTEGRATED FARMING
The rationale behind integrated farming is to minimize wastes from the various subsystems on the farm: wastes or by-products from each subsystem are used as inputs to other subsystems to improve the productivity and lower the cost of production of the outputs of the various subsystems (Edwards et al., 1986).
Integrated fish farming is generally considered particularly relevant to benefit the rural poor. In Asia, fish farming has been a part-time activity of peasant farmers, who developed it as an efficient means of utilizing farm resources to the maximum capacity.
Integrated farming can paly a role in increasing employment opportunities, nutrition and income of rural populations and has received considerable attention in recent years. Besides many developing countries of Asia, some in Africa (Central African Republic, Cote d'Ivoire, Cameroon, Zambia) and South America (Brazil, Ecuador, Panama) have introduced this system on a pilot or larger scale. Some of the East European countries (Hungary, Czechoslovakia, Poland) have expanded and improved in recent years, the practice of integrating animal production with fish culture (Pillay, 1990).
Simultaneous production of fish in ponds, with pigs, duck or chicken rearing in pens, beside or over the ponds constitutes a continuous organic fertilization of the pond by the livestock. This practice increases the efficiency and rentability of both livestock farming and fish culture through the profitable utilization of animal and feed wastes (Vincke, 1988).
INTEGRATED FARMING OF FISH AND LIVESTOCK
The highest productions obtained so far in integrated fish farming are with pigs, ducks and chicken, a very widespread technique in Asia (Edwards et al., 1983, 1986). In some countries, fish farmers also integrate geese, rabbits, goats, sheep, cattle and the water buffalo with fish culture, on a smaller scale.
The main fish species stocked in animal-fish pond systems, either in mono or polyculture are the common carp, the Chinese and Indian carps and Oreochromis niloticus. A number of other species such as Pangasius sp., Clarias gariepinus Burchell, hybrid of tilapia, grey mullet and eels are also raised, mainly in polyculture. Stocking densities and species composition vary considerably from system to system and sometimes from country to country, depending upon several factors.
Pig and Fish Farming
Pigs are reared in pens or sties built on the banks of the fish ponds (and wastes are washed out) or constructed over the ponds on piles or wooden stilts and have a lattice type of floor (allowing wastes to fall directly into the pond). The number of pigs per ha of ponds area varies from 40 to 300, according to the literature. However, the number of piglets recommended is generally 100 per ha (or 1 piglet per 100 m2 of pond).
Piglets are weaned at two months (average weight 12–15 kg) and are ready for fattening. They reach 70–85 kg after 6–7 months.
In China fish ponds stocked with 60,000 fingerlings per ha (average weight 20–30g) of different species raised together with about 45–75 pigs/ha produced between 2–18 t. of fish and 4–7 t. of pigs (live weight) per ha/year (Pillay, 1990).
Polycultures were conducted in the Philippines with Oreochromis niloticus (85 %), common carp Cyprinus Carpio Linnaeus (14%) and Ophiocephalus striatus Bloch (1%) at stocking rates of 10,000 and 20,000 fingerlings/ha, combined with pigs (average initial weight 20 kg) at 40–60 animals/ha during a 90 day test period. The best results were obtained with the 60 pigs - 20,000 fish/ha, or 1950 kg (1.95 t) of fish/ha/90 days and 60 pigs at an average weight of 57 kg (3.42 t). The total gain in weight of the 60 pigs was 2,220 kg (2.22 t) (live weight) in 90 days (Cruz and Shehadeh, 1980). In 3 cycles of 90 days (270 days) the combined production could reach 3,866 kg (3.87 t) of fish and 6,660 kg (6.66 t) of pigs.
In some African countries (Central African Republic, Cameroon, Congo, Cote d'Ivoire, Gabon), in ponds stocked with T. niloticus at a rate of 20,000 fingerlings/ha, the combined production can reach 8,000 kg (8 t) of fish and 6,000 to 9,000 kg (6–9t) of pigs (on the hoof) per ha/year (Vincke, 1976).
With T. andersonii (monoculture) combined with pigs, 7,000 kg (7 t) of fish per ha/year were obtained in Zambia. Monoculture of Clarias gariepinus with pigs yielded 7,510 kg (7.51 t) of fish per ha/year in Central Africa. The grow out period was 90 days and the daily growth rate of C. gariepinus was 2.9 g/day (Vincke, 1988).
In a polyculture, 20,000–30,000 fingerlings/ha of O. niloticus and 1,000–10,000 C. gariepinus fingerlings/ha integrated with 100–200 pigs/ha and small quantities of brewery waste and spoiled flour, the average yield of 4 trials was 11,140 kg (11.14 t) of fish per ha/year (Vincke, 1988).
If for socio-cultural reasons pig farming is not possible, the combination of chicken or ducks and fish is recommended.
Duck and Fish Farming
As presently practised, the combination of duck and fish farming is considered as a means of reducing the cost of feed for ducks and a convenient and inexpensive way of fertilizing ponds for the production of fish (Pillay, 1990). In this integrated system, ponds provide living and foraging areas for the ducks and fish.
Ducks are reared in shelters built on the banks of the ponds or constructed over the ponds on stilts, or sometimes built on floating platforms. The ducks should be kept away from the dykes of the ponds since they search for insects, frogs and snails, damaging the earthen walls with their beaks and provoking erosion and the collapse of the dykes. Fencing inside the pond is therefore recommended. Ducks are known to eliminate almost all the snails in ponds in depths of up to 30–40 cm, thus controlling the immediate host of bilharziasis.
There are different duck strains. Peking ducks are used in Central Europe, China, the Philippines, Africa and Latin America. The Khaki-Campbell strain is raised in Thailand and the mule duck in Taiwan. Muskovy ducks are sometimes used in Africa. Each strain has different fattening periods and a marketable size of 2.0–2.8 kg is obtained within 7–9 weeks, depending on the strain, the size at stocking and feeding.
Ducks are reared at different densities, depending on the climatic conditions, the method of raising (extensive or intensive), water quality, and other factors.
In Eastern Europe (where the growing season is only about 150 days) 150–500 duckling are stocked per ha of pond; in Asia between 750 and 4,000 ducklings are stocked per ha, and in Africa and Latin America, 1,000 to 1,500 duckling are stocked per ha.
In Hong Kong, in a system with 2,500–3,500 ducks/ha/year integrated with the polyculture of Chinese carps, 5–6 t. of duck meat and 2,750–5,640 kg/ha/year of fish has been produced (Delmendo, 1980).
Demonstration trials conducted in India in polyculture of Indian and common carps (at a stocking density of 6,340 fingerlings/ha) raised with ducks (100/ha) have yielded 4,323 kg of fish/ha/year, 250 kg of ducks (live weight) and 1,835 eggs (Jhingran and Sharma, 1980).
In the Philippines, comparative polycultures were implemented during two 90 day test periods, with O. niloticus (85%), common carp (14%) and Ophiocephalus straitus (1%), at stocking rates of 10,000-20,000 fingerling/ha, combined with Peking ducks at 750–1,250 ducks/ha. The highest net yields 1.69 t/ha of fish in 90 days were obtained with the 750 ducks: 20,000 fish stocking combination. Combining the two 90 day periods, the highest fish yields were 2.58 t/180 days with the 1,250 ducks: 20,000 fish stocking combination and 2.42 t/180 days with the 750 ducks: 20,000 fish stocking combination (Cruz and Shehadeh, 1980).
In Taiwan, approximately 3.5 t/ha/year of fish (without additional fertilization or supplementary feeding) have been achieved by raising 1,500 ducks/ha (Chen and Li, 1980).
Raising 1,000–2,000 ducks/ha on ponds in Vietnam, increased the average fish yield to 5 t/ha/year from 1 t/ha/year without ducks (Delmendo, 1980).
In Hungary, a yield of 1.6 – 2 t/ha/year of fish is obtained in polyculture of Chinese carps and common carp integrated with 500 ducks/ha. The duck production is between 1,000 and 1,200 kg/ha (Woynarovich, 1980).
In the Central African Republic, ponds stocked with O. nilotius (20,000 fingerlings/ha) and Clarias gariepinus (100 fingerlings/ha), combined with 1,500 Peking ducks/ha have produced 3.8–4.5 t of fish/ha/year and between 4–6 t/ha/year (live weight) of ducks (Vincke, 1976).
Trials conducted in Madagascar, in the cool forestry area, using common carp (2,500 fingerlings/ha) and O. niloticus (between 2,500 and 10,000/ha) integrated with ducks (1,5000 ducklings/ha), yielded 1.8-2.5 t/ha/year of fish and 2.0–2.5 t/ha/year of ducks (live weight) (Vincke, 1976).
In Zambia, O. andersonii integrated with Peking ducks, yielded of 5 t fish/ha/year.
In Ecuador, O. nilotius at stocking densities of 4,500 to 8,000 fingerlings/ha integrated with ducks (800 to 1,500/ha), farmers obtained between 3.3 and 4.67 t fish/ha/year and 1.76–3.75 t/ha/year of duck (Vincke and Schmidt, 1979).
In Israel, Wohlfarth (1978), quoted by Edwards (1980), reported a fish yield of about 40kg/ha/day, which can be extrapolated to 14.6 t/ha/year in a fish pond integrated with ducks.
Chicken and Fish Farming
The integrated farming of chickens and fish is only practised in a few countries in Asia (Philippines, China, Indonesia, Thailand). Trials of chicken integrated with fish farming have also been conducted in Africa (Central African Republic, Cote d'Ivoire, Gabon and Madagascar), in Latin America (Ecuador, Panama) and in the USA. Not all the results of these experiments have been published.
Chicken (broilers or layers) are reared in pens beside or over the ponds, in the traditional way, in roughly the same conditions as ducks, generally at a density of 1,000 to 6,000 chickens/ha.
In the Philippines, in fish polyculture (O. niloticus, common carp and snakeheads with broilers (up to 5,000/ha), an extrapolated yield of about 7.3 t of fish/ha/year was obtained (20 kg/ha/day) (Little and Muir, 1987).
In Indonesia, in monoculture of Puntius gonionotus in a 400 m2 pond (stocking rate of 125 kg of fingerling/ha) integrated with 6,000 layers/ha during a culture period of 3 months, the extrapolated yield was 5.1 t of fish/ha/year, plus 54,750 eggs/year (Djajadiredja et al., 1980). In polyculture of Osteochilus hasselti C. & V. (33% in weight), common carp (19%), Helostoma temmincki (29%) and Puntius gonionotus (19%) in a 2,408 m2 pond (stocking rate of 872 kg of fish/ha) integrated with 120 broilers/ha during a culture period of 3 months for the fish and 2 months for the chickens, the extrapolated yield was 10.8 t of fish/ha/year, plus 1,395 kg/ha/year of chickens (Djajadiredja et al., 1980).
In the Central Plain of Thailand a three-tier system is applied where chicken are raised above the pigsty constructed over the fish pond. In this combination, the chicken droppings are eaten by the pigs and, whatever is not consumed, is washed down to the pond with the pig manure, both as fish food and fertilizer. The total production of a 1.5 rai (=2400 m2) pond area is 4 t of Pangasius pangasius (equivalent to 16.67 t of fish/ha/year). 8 t of pigs (42 pigs/2400 m2 of pond, equivalent to 33.3 t of pigs/ha/year) and 15,330 chicken eggs from 60 hens/2400 m2 (equivalent to 63,875 eggs per ha/year) (Delmendo, 1980).
In the Central African Republic, egg laying chickens (at a stocking density of 3,000 chickens/ha) integrated with O. niloticus (30,000 fingerlings/ha), during a grow-out period of 189 days in 500 m2 ponds, have produced an extrapolated yield of 5.5 t of fish/ha/year, plus 2,746 eggs/year.
According to Burns and Stickney (1980), in Little and Muir (1987), chickens (4,000 broilers/ha of pond) raised with Oreochromic aureus Steindachner yielded 5.9 t of fish/ha/year in the USA.
Integrated Farming of Other Animals Combined with Fish
According to Pillay (1990), the culture of geese integrated with fish farming is practised on a very limited scale in East European countries and in Hong Kong. Geese have also been raised more extensively on fish ponds in Thailand (Little and Muir, 1987) and geese-fish trials have been conducted in Madagascar (Vincke, 1976).
The geese are fattened in sheds build over the ponds. The floor is covered with wire netting or with lattice work, allowing goose droppings into the pond. A slanting platform extends from the shed into the pond to allow the geese to enter a fenced area of the pond.
In Hong Kong, in polyculture of grey mullet (38%), grass carp (23%), common carp (21%), silver carp (9%) and bighead carp (9%), at a stocking rate of 12,2000 fish/ha, integrated with geese (4,000 to 4,500 geese/ha), yields of 3.69 t/ha/year of fish and 2.25 t of geese (live weight)/ha/year were obtained (Sin, 1980).
In Madagascar, with geese (stocking density of 500–800/ha) raised over ponds stocked with O. niloticus (10,000–20,000 fingerlings/ha) and common carp (2,500 fingerlings/ha), fish yields of 2.62 to 2.47 t/ha/year were obtained and 250–600 kg of geese (live weight) per ha/year (Vincke, 1976).
In some countries, small ruminants such as goats and sheep are integrated with fish culture. According to Djajadiredja et al., (1980), integrated sheep-fish farming is practised, but on a very small scale, in West Java. In a 84 m2 pond stocked with 2,500 giant gouramy fingerlings integrated with 4 sheep raised over the pond, a total production of 200 kg of small fish (extrapolated yield of 20.83 t/ha/year of fish) and 4 sheep of about 20 kg each and 2 lambs were obtained. Integrated cattle-fish farming is practised in some of the farms in China and Vietnam. In Vietnam, using a polyculture of Chinese carps and common carp combined with about 30 dairy cattle stalled near the pond, fish yields of 6 to 8 t/ha/year were achieved. Trials have also been conducted Israel, Ecuador and Brazil. The cattle sheds are generally situated near the fish ponds and the slurry is conveyed through pipes or canals directly into the ponds.
In Israel, a mixed age polyculture of carp and tilapia was experimentally integrated with 57 dairy cows, over the 126 day rearing period to nearly 400 cows/ha of fish pond. In such conditions, fish yields of over 30 kg/ha/year were observed, equivalent to 10.95 t/ha/year (Little and Muir, 1987).
It has been proposed (Edwards, 1983) for smallscale farmers to integrate the water buffalo with fish farming at a ratio of about 85 buffaloes/ha of fish pond. The expected fish yield would be around 17.5 t/ha/year.
Integrated rabbit-fish farming is practised only on a very small scale. This system has up to now not received much attention, except in Cameroon (where the Africans consider the rabbits as “pelleting machines”) and in Ecuador and Thailand, on an experimental basis.
A pigeon-fish system is also practised on a very small scale in Hong Kong (Sin, 1980), but no information is available on this integrated system.
PRESENT STATUS OF INTEGRATED FARMING OF FISH AND LIVESTOCK.
It is clear that integrated livestock-fish farming systems are mainly concentrated in Asia. In recent years however, some of these systems have been successfully applied in other developing countries and impressive fish yields have been obtained. Except in the state-owned farms and cooperatives in Eastern Europe, China and Vietnam, integrated livestock-fish farming is practised mostly on a small scale level, by rural communities. The aims of the farmers are to make use of their land at the lowest cost and to increase their income. In Asia, the integrated production systems have been developed empirically by the farmers themselves and are still largely aimed at fulfilling only their own food requirements (Rajbanshi and Shrestha, 1980).
In the social and economic conditions prevailing in developing countries, integration of livestock may be the only source of fertilizers available, at low cost, to make fish culture economically feasible.
In South America, experiments have shown the technical feasibility and the expansion potential of integrated livestock-fish farming in Panama and Ecuador. The technical and economic feasibility of some integrated systems has been demonstrated in several African countries and is now practised on a small scale in Cameroon, Central African Republic, Congo, Cote d'Ivoire, Madagascar, Malawi and Zambia.
In Western Europe and in the USA, only sporadic and limited trials on integrated fish farming have been conducted.
FUTURE DEVELOPMENT OF LIVESTOCK-CUM-FISH PRODUCTION.
The commercial aquaculture enterprises focus on the production of expensive luxury species for export, and thus fish are not for local consumption. To resolve the persistent and widespread malnutrition in developing countries, it is absolutely necessary to increase the availability of animal products, at prices that the masses can afford. As pointed out by New (1991), fortunately most farmed fish is raised in ponds receiving organic fertilization. This must remain so if aquaculture is to play its role in “feeding the masses”. This again emphasizes on integrated aquaculture (New, 1991).
The potential for integrated aquaculture exists in many developing countries but more research is needed if the development of integrated livestock-fish farming systems is to be enchanced. Socio-cultural factors should be given due consideration together with the economic and technical feasibility studies. Successful trials and demonstrations have been carried out in developing countries, but more comparative feasibility studies on the economics of the different livestock-fish farming systems have to be conducted, analyzed and published. On-farm tests are of particular interest and should be planned and implemented to generate the information that is now lacking. One has to remember that most of the farmers do not keep any records concerning their investment, cost of labour and inputs.
Some of the economic aspects of integrated fish farming have been described by several authors (Delmendo, 1980; Djajadiredja et al., 1980; Edwards et al., 1986; Lovshin et al., 1986; Shang and Costa-Pierce, 1983; Sin, 1980; Tan and Khoo, 1980; Vincke, 1976). As stressed by Shang and Costa-Pierce (1983), most of the economic aspects concentrate on rudimentary budget analysis which estimates costs of production and profit of operation. Such studies, usually provide little sensitivity analysis in relations to variations of production, input costs and market prices.
It is likely that fish farming combined with animal husbandry will be introduced and developed in many tropical countries where small scale rural fish farming already exists. The integrated farming systems are potentially important in raising the income level as well as the standard of living of small-scale farmers. Most of the farmers are lacking technical knowledge which must be remedied by realistic technical assistance. Reliable quantitative production and management guidelines are yet to be generated, recorded and disseminated to serve as a baseline for development programmes (Pullin and Shehadeh, 1980).
In October 1986, the ICLARM (International Centre for Living Aquatic Resources Management) has organized an UNDP/ICLARM funded workshop “Towards a research framework for tropical integrated agriculture-aquaculture farming systems” as part of the information-gathering process to produce a study on “Research and Education for the Development of Integrated Crop-Livestock Fish Farming Systems in the Tropics” (Edwards et al., 1988). This study could serve as the baseline for the implementation of future research and training programmes on integrated fish farming in the tropics.
How will the development and the production of the livestock-fish culture systems evolve in the different regions? Predictions are always very difficult but are necessary. One may reasonably predict that Asia will keep the lead by improving and developing the existing traditional integrated systems. The farmers will progress in terms of productivity and efficiency. It is not easy, and almost impossible, to predict how the existing state-owned integrated systems in Eastern Europe will evolve because of the rapid political and economic changes occurring there. Even if some livestock-fish farming trials have been conducted in the USA and in Western European countries, the results obtained will not influence the commercial fish farmers. There are no reasons to believe that this will change in the near future.
The situation is different in Africa and Latin America where fish farming has been practised only since 30–40 years ago, compared to Asia with its two millennia of aquaculture experience (New, 1991). I believe that in the countries where small-scale fish farming is already practised, more farmers will use the integrated systems. This will only be possible with the help of active and efficient extension programmes. This process, to be successful, will need development aid for a long period. As stressed by Micha (1991), agencies for bilateral and multilateral cooperation should become more aware of the potential of integrated fish farming for the developing countries, especially in Africa and Latin America, and should finance well-planned development projects to promote fish farming integrated with rural development.
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