AQUAFEEDS AND FEEDING STRATEGIES IN BANGLADESH
M. Zaher and M. A. Mazid

Freshwater Station, Fisheries Research Institute Mymensingh, Bangladesh

ZAHER, M. and M.A. MAZID. 1993. Aquafeeds and feeding strategies in Bangladesh, p. 161-180. In M.B. New, A.G.J. Tacon and I. Csavas (eds.) Farm-made aquafeeds. Proceedings of the FAO/AADCP Regional Expert Consultation on Farm-Made Aquafeeds, 14-18 December 1992, Bangkok, Thailand. FAO-RAPA/AADCP, Bangkok, Thailand. 434 p.

INTRODUCTION

Fish and fisheries play a significant role in the economy of Bangladesh in terms of nutrition, income, employment and foreign exchange earnings. The people of Bangladesh depend on fish as the principal source of animal protein. Fish contribute about 80% of the nation's animal protein intake, nearly 6% to GDP and more than 12% to the export earnings of the country (G.O.B. 1990). Approximately 1.4 million people depend on fisheries as their primary source of income and another 11 million are involved in seasonal or part-time fishing and other ancillary fishery activities. About 73% of the rural households are involved in subsistence fishing. The sector provides employment to about 8% of the population.

The country has abundant water resources with 1.5 million ha of perennial and 2.8 million ha of seasonal inland waters, in addition to a coastline of 480 km. There are approximately 1.3 million freshwater ponds covering a total area of about 150,000 ha, out of which nearly 46% are under culture, 30% are culturable and 25% are derelict (F.R.S.S. 1987). At present fish production from these ponds is low, at 600-800 kg/ha/yr. The average fish production was 1,175 kg/ha for cultured ponds, 300 kg/ha for culturable and 175 kg/ha for derelict ponds. The country has 5,000 ha of oxbow lakes (baors) which also contribute to aquaculture production.

There are about 2.5 million ha of coastal lands, large parts of which are suitable for shrimp farming. Coastal aquaculture of black tiger shrimp (Penaeus monodon) has been identified by the government as a priority area. Shrimp farming in “beries”, “ghers” or “ghonas” (i.e. areas impounded by dikes) of the coastal area is an old traditional practice. However, its rapid expansion in the past few years is the most remarkable development in the fishery sector of Bangladesh, which is linked with increasing demand for shrimp in the world market. The production in 1987-88(18,000 t) increased by a factor of nine over 1982-83 (2,000t). This increase was largely due to an expansion in the area of coastal shrimp farming, from only about 20,000 ha of brackishwater ponds in 1980 (Mahmood and Chowdhury 1989), to an area of about 150,000 ha in 1989. Unfortunately, the shrimp yields of the coastal farms are very low (120-200 kg/ ha/yr), mainly due to lack of feed and proper management.

Fish production

Bangladesh ranks third in inland fish production among the countries of the world (Islam 1989, Ahsanullah 1989). The current level of production (1990) of fish and shellfish is estimated to be about 850,000 t, out of which 610,000 t (72%) comes from inland waters and 240,000 t (28%) from marine fisheries. Of the inland production, 420,000 t (69%) is from capture fisheries and 190,000 t (31%) from culture (G.O.B. 1991). Capture fisheries show a decreasing trend, while output of culture fisheries increases.

Aquaculture production

Aquaculture production systems in Bangladesh are diversified in type, character and source, constituted by ponds, tanks, oxbow lakes (baors) and coastal shrimp farms. Details of aquaculture production from 1985-86 to 1989-90 are shown in Table 1 and Figure 1.

Source: G.O.B. (1990)

Figure 1. Aquaculture production in Bangladesh

Major cultured species

Pond aquaculture in Bangladesh comprises mainly Indian major carps (Labeo rohita, Catla catla, Cirrhinus mrigala, Labeo calbasu, etc.), catfishes (Clarias batrachus, Heteropneustes fossilis, Mystus aor, M. tengra, Ompok pabda), snakeheads (Channa punctatus, C. striatus, C.marulius), climbing perch (Anabas testudineus), freshwater prawns (Macrobrachium rosenbergii) and many small indigenous species. Pond culture of Macrobrachium is a new practice in Bangladesh. Some exotic fishes, like tilapia (Orechromis niloticus), silver barb (Puntius gonionotus), common carp (Cyprinus carpio), silver carp (Hypopthalmichthys molitrix), grass carp (Ctenopharyngodon idella), African catfish (Clarias gariepinus), etc., are being also cultured in ponds. Tilapia and silver barb are cultured in small water bodies, such as ditches and shallow ponds. Indian major carps, Chinese carps, catfishes, snakeheads and small indigenous fishes are used in oxbow lake (baor) aquaculture. Coastal aquaculture is based mainly on black tiger shrimp (Penaeus monodon). Macrobrachium culture is also practiced in low salinity areas.

Indian major carps and Chinese carps contribute about 47% while shrimp, the main source of export earnings from aquaculture, contribute about 14% to the total aquaculture production (Figure 2). Individual production data of different species are not available. Details of aquaculture production by major species groups are given in Table 2.

Figure 2. Aquaculture production by major species groups in Bangladesh in 1989/90

* “others” include tilapia, silver barb, snakehead, etc.

Source: Department of Fisheries, Dhaka

Importance of aquafeeds

Against a backdrop of rapid population increase without concomitant increase in fish production, the per capita consumption of fish has dropped from 33 kg in 1963-64 to 20.5 kg in 1989-90, compared to the recommended level of 38 kg (G.O.B., 1985). As a principal source of animal protein, fish production has to be increased manifold to meet the requirement in Bangladesh. In order to achieve the targeted production of 1.2 million t by the terminal year of the Fourth Five Year Plan (1995) production has to be increased by nearly 25% over 1990. Scientific opinion is that fish production as high as 3,700-4,500 kg/ha could be obtained by using semi-intensive polyculture in ponds with supplementary feeding. This demonstrates a real possibility of increasing production and reveals the potential importance of aquafeeds in Bangladesh. Recently some shrimp farmers began to use supplementary and/or complete feeds for shrimp culture, which increased production from 200 kg/ha to 1,200-1,600 kg/ha.

Contribution of feed to aquaculture

The use of feed is increasing with the expansion of aquaculture in Bangladesh. Nursery farmers use rice bran and mustard oil cake for carps. The unit feed price is US$ 0.10-0.15/kg, and the total costs of feeding are US$ 325-672/ha, 10-20% of the total production cost of US$ 3,416-3,524/ha. In polyculture, farmers use a mixture of rice bran and mustard oil cake, which costs US$ 0.06-0.10/kg. The total production cost is US$ 1,833/ha and the total cost of feeding is US$ 510/ha (28%). Semi-intensive culture of tilapia and silver barbs with supplementary feed, composed of rice bran and mustard oil cake (US$ 0.08/kg of feed), has a total production cost of US$ 3,115/ha, while cost of feeding is US$ 1,524 (49%) resulting in an increase in production from 560 kg/ha/yr to 1,300 kg/ha/yr. Some shrimp farmers use complete pelleted shrimp feeds priced at US$ 1.00/kg. Their total cost of feeding is US$ 610/ha, 39% of the total production cost of US$ 1,574/ha. Feeding increases the yield from 120-200 kg/ha to 1,200-1,600 kg/ha. Farmers shift gradually from no feed, through the use of farm-made feeds, to factory-made feeds.

AVAILABILITY OF FEED INGREDIENTS

Since the demand for suitable fish feeds is increasing day by day with the gradual intensification of aquaculture practices, a nationwide survey was conducted by the Fisheries Research Institute to identify potential fish feed ingredients based on their availability, price and primary nutritional value. Eighty- three different types of ingredients, both of plant and animal origin, were studied. The survey covered both traditional ingredients and non-conventional items, such as kitchen wastes, slaughterhouse wastes, processed wastes from the food industry, aquatic weeds, etc., which are not being properly utilized. Most of these conventional and non-conventional ingredients are abundantly available in Bangladesh at an affordable price for making good quality fish feeds.

As Bangladesh is mainly agro-based, a large variety of agricultural wastes and by-products, such as pulse brans, oil seeds and oil cakes, and molasses are being used as fish feeds. In addition, the country has a vast water area supporting huge quantities of aquatic plants and weeds. Aquatic plants, like water hyacinth, duckweed, water velvet, etc., have been tried as fish feed ingredients. Feed ingredients of animal origin, like fish meal, are used as sources of animal protein in aquafeeds. Others, including poultry by-products, slaughterhouse wastes, blood meal, bone meal, etc., have been evaluated for their possible use. Even in small amounts, they may greatly improve the nutritional value of the entire diet.

Information on price and availability of major fish feed ingredients are shown in Tables 3 and 4. It was observed that the availability and price of agricultural by-products suitable for fish feeds is largely seasonal. Although most are available throughout the year and all over the country, some are very localized. On the other hand, most have peak seasons, when their prices are lower than in the off-season.

Rice bran is extensively used for feeding fish, being the cheapest and most commonly available feed ingredient. Wheat bran is also used in feed formulation. Mustard oil cake and sesame oil cake are sufficiently available year-round, throughout the country, to be used in fish, poultry and livestock feeds, either individually and in combinations with other ingredients. Molasses and flour are used as binders.

Proximate composition of potential fish feed ingredients was determined by A.O.A.C. methods (A.O.A.C. 1985). Although the information generated does not provide a complete picture of their nutritional value, it is adequate for their selection for feed formulation by farmers and for further research on the formulation and manufacture of good quality fish feeds by scientists. Proximate analyses of the major fish feed ingredients available in Bangladesh are presented in Table 5.

The import of major feed ingredients is still not allowed by the govern- ment. However, the matter is under active review.

* obtainable free of charge; however, commercially collected volumes are priced

Source: F.R.I. (1989)

* obtainable free of charge; however, commercially collected volumes are priced

Source: F.R.I. (1989)

Source: F.R.I. (1989)

AQUAFEED MANUFACTURING INDUSTRY

The success of intensive and semi-intensive fish culture depends to a large extent on the application of suitable feeds, although other considerations, such as stocking density, the ecology of the water body, the physico-chemical conditions of the water, etc., also have a bearing. Fish feeds provide nutrients for optimum fish growth and bring higher economic return to farmers.

Although Bangladesh is rich in water resources suitable for aquaculture, intensive aquaculture is almost absent and semi-intensive aquaculture is only a recent trend. Thus the demand for compounded complete and supplementary feeds is very low, being only 3,000-4,000 t/yr. Moreover, farmers make their own aquafeeds on-farm. Because of low demand, the fish feed industry has not yet developed. Recently (1990) an aquafeed mill named Saudi-Bangla Fish Feed Mill was established by the Saudi-Bangla Industrial and Agricultural Investment Company, as a joint venture between Saudi Arabia and Bangladesh. Its equipment was supplied by the Nanlien Corporation, Taiwan, and the mill was installed under the consultancy and engineering services of the supplier. Originally the mill was designed to produce shrimp feed, with a capacity of 6,000 t/yr but fish feed manufacture is also feasible and said to be in effect.

The major ingredients for manufacturing the compound shrimp and fish feeds of this mill are local. Some minor ingredients, like growth promoting substances (di-calcium phosphate, di-sodium phosphate, etc.), fungicides, and binders, are imported from Singapore, Taiwan and Thailand. The ingredients used for (complete) shrimp feeds include fish meal,shrimp shell meal, soybean meal, wheat flour, di-calcium phosphate, and vitamin/mineral premix. In (supplementary) fish feed formulae, fish meal, shrimp shell meal, sesame oil cake, coconut oil cake, rice bran, wheat bran, wheat flour, di-sodium phosphate and vitamin/mineral premix are used. Both shrimp and fish feeds are produced by the company in dry, pelleted form. Details of the feeds made are given in Tables 6 and 7. The address of this sole aquafeed manufacturer is: Saudi-Bangla Fish Feed Mill, Bhaluka, Mymensingh, Bangladesh. Its head office address is: Saudi-Bangladesh Industrial and Agricultural Investment Co., Steel House (5th Floor), Kawran Bazar, Dhaka, Bangladesh.

ON-FARM FEED FORMULATION AND MANUFACTURING

In traditional fish culture, farmers stock their ponds but usually do not use any supplemental feed. With increasing demand and market value, farmers are now beginning to use supplementary feeding to increase the production of cultured fish.

* sold for both carp and catfish

The formulae of farm-made feeds, used by farmers or researchers for various cultivated species, are diverse. Some farmers use only rice bran for both carp nurseries and grow-out ponds. Some also use rice bran for tilapia and silver barb culture. Sometimes substitution of wheat bran for rice bran is tried by scientists and farmers for tilapia and silver barb culture and also for carp nursery operations. Some carp nursery operators use only mustard oil cake or sesame oil cake, soaking it with water for several hours before spreading it over the pond surface.

Other carp nursery operators formulate feeds with various proportions of mustard oil cake and rice bran, ranging from 40:60 to 60:40, in a dry, nonpelleted form. Sometimes sesame oil cake and wheat bran are substituted. Scientists using a carp nursery feed composed of rice bran (50%), mustard oil cake (25%) and fish meal (25%) got higher survival and better growth than with farmers feeds (Haque and Hossain 1991). Another carp nursery feed formulated of silk-worm pupae (25%), sesame oil cake (50%), wheat bran (21%), vitamin/ mineral premix (1%) and molasses (3%) when fed to rohu (Labeo rohita) fry was found to promote higher growth and survival (Zaher et al. 1992). An alternative improved nursery feed is shown on Figure 3.

In carp polyculture farmers use a mixture of rice bran (50%-80%) with mustard oil cake or sesame oil cake (20-50%) (Figure 4). The hand-made feed is usually formed into wet, non-pelleted balls (Figure 5) but sometimes it is prepared as a dry, non-pelleted mixture. Most fish farmers feed their broodstock with a supplementary feed comprising of 50% rice bran or wheat bran, 45% mustard oil cake and 5% fish meal (Islam 1989).

In catfish (Clarias batrachus, Clarias gariepinus, Ompok pabda, Mystus tengra) nurseries, live feeds, such as Tubifex and sometimes zooplankton are used. For catfish grow-out some farmers use a mixture of 40% fish meal, 40% mustard oil cake and 20% rice bran in non-pelleted moist form.

Farm-made shrimp feeds with 60% animal viscera, 20% rice bran and 20% wheat flour, or with 40% fish meal, 35% rice bran and 25% wheat flour are fed moist, or sun-dried, stored and used later (Karim 1986).

Farmers do not use any equipment to prepare feed, they are made by hand. Locally made sieves are used to sift the ingredients. On the other hand scientists use a mixer and mincer (Figure 6). A simple pellet mill is also used in research work, supplied by David Brown, Radicon, England.

Figure 3. Improved formulated carp nursery feed with 30% protein content (50.0% mustard oil cake, 24.9% rice bran, 21.1% fish meal, 3.0% molasses and 1.0% vitamin premix)

Figure 4. Traditional farm-made feed mixture (75% rice bran and 25% mustard oil cake) for carp polyculture

Figure 5. Manual preparation of farm-made moist feed balls (75% rice bran, 25% mustard oil cake)

Figure 6. Preparation of improved formulated feed for carp polyculture (20% protein content)

ON-FARM FEEDING STRATEGIES

Proper utilization of feed largely depends on feeding rates and frequencies. For nursery management of carps, farmers apply feed at 3 times the total stocking biomass, and increase this volume by 2 kg/ha every 10 days until the end of the 60 day nursing period, with a stocking density of 2-3 kg/ha and a fertilization rate of 1,500-2,500 kg/ha of cow dung, or 25 kg/ha of urea and 19 kg/ha of TSP, every 10 days. Feeding is usually twice a day, morning and afternoon. Feeding rates and frequencies vary from farmer to farmer. Some farmers apply feed only once a day, while others apply feed every alternate day or irregularly.

For the grow-out of carps and catfish farmers apply feed at the rate of 2-8% of the body weight, once a day, usually in the morning. Sometimes feed is given every alternate day or without any schedule. Water exchange is not practiced, nor is there provision for it.

In shrimp farming farmers apply feed at 7-15% of body weight per day for nursery management and 5-10% per day for starter, both twice a day (usually early morning and evening). Grower and finisher feeds are fed at 3-5%, once a day, either in the early morning or evening.

MAJOR INSTITUTIONS INVOLVED IN AQUAFEED RESEARCH AND DEVELOPMENT

The Fish Feed and Nutrition Division of the Fisheries Research Institute has been involved in aquafeed research and development since its inception in 1986. The Fisheries Faculty of the Bangladesh Agricultural University has also been involved in basic aquafeed research. Names and addresses of these two institutions and the principal investigators, with their area of study, are given in Annex 1.

CURRENT NATIONAL REGULATIONS

As the manufacture of aquafeeds is new to Bangladesh, no specific regulations are existent to control their processing or sale. The government has allowed the aquafeed industry to develop under industrial regulations. Existing import policies do not permit the import of aquafeeds or feed ingredients, other than chemical-like ingredients. Each manufactured product must be tested and certified by the Bangladesh Standard and Testing Institution before marketing under the regulations in practice.

CURRENT PROBLEMS AND CONSTRAINTS

Though Bangladesh has vast water bodies suitable for aquaculture, fish and shrimp culture is still traditional in nature. Intensive aquaculture is not yet practiced and semi-intensive aquaculture is a recent thrust. Current problems and constraints in the manufacturing and use of aquafeeds in the country are:

• demand for and use of manufactured aquafeeds is very low and not yet conducive to the development of commercial production;

• information on the nutritional requirements of Indian major carps for grow-out fish are available but not for nursery and broodfish. For catfish and other target species, nutritional studies are incomplete and knowledge is insuf- ficient for the formulation and manufacture of feeds;

• information on the digestibility of locally available ingredients is not available;

• some important ingredients, such as good quality fish meal, soybean meal, growth promoting substances, fungicides and preservatives are not avail- able;

• some potential fish feed ingredients, such as blood meal, viscera meal, slaughterhouse wastes, poultry processing wastes, silkworm pupae, etc., are not available in processed and refined form;

• research on the development of suitable aquafeeds is incomplete and hence no technology is available to produce good quality aquafeeds on a commercial basis;

• skilled manpower in fish feed manufacturing and fish nutrition is insufficient;

• funding for research and development is inadequate. Lack of proper equipment and machinery seriously hinders aquafeed research and develop- ment;

• current transportation and marketing systems for commercial aquafeeds are not well organized;

• extension work to motivate farmers to use aquafeeds in order to increase production and economic benefits is inadequate;

• above all, the poor socio-economic conditions of farmers does not permit the use of feed for fish and shrimp culture. Bangladesh is a poor developing country where the per caput income is very low; farmers cannot afford considerable expenditure on aquafeeds. This is the greatest constraint on the manufacturing and use of aquafeeds.

TRENDS IN AQUAFEED MANUFACTURING AND USE

The Fisheries Research Institute, the Directorate of Fisheries, the Bangladesh Agricultural University and various non-governmental organizations (NGO's) have been working to increase aquaculture production in Bangladesh. Farmers, hatchery and farm owners are now more aware of the need to use aquafeeds to increase production. An increasing trend in the use of shrimp feed in coastal shrimp farming is being observed. About 10-15% of the shrimp farmers now use supplementary or complete feeds and achieve production levels of 1,000-2,000 kg/ha compared with 120-200 kg/ha without feed. This en- couraging result inspires others to use shrimp feeds also.

Recently, pond aquaculture has increased tremendously. Many ponds are now under improved aquaculture practices, with the supervision of the above-mentioned organizations. Production has increased from 600-800 kg/ha without feeding to 2,000-3,000 kg/ha when farmers use aquafeeds. Farmers are now becoming more interested in carp polyculture, fish seed production and catfish culture. Trends in applying aquafeeds in pond culture, especially in carp polyculture and fish seed production, are encouraging. The use of fish feeds in pond aquaculture has increased from 5-10% to 15-20%.

Due to increasing demand for aquafeeds, investors have now taken keen interest in the establishment of new mills. Two private enterprises, Rakamary Matsha Khamar and Bengal Fisheries International, have already planned to establish new fish/shrimp feed mills. In this connection, the proprietor of Rakamary Matsha Khamar has already communicated with FRI and the Saudi-Bangla Fish Feed Mill and has visited Singapore. There is hope that the new mills will be established in the near future.

LIST OF REFERENCES

Ahsanullah, M. 1989. Fisheries extension and credit in Bangladesh, p 84-92. In Proceedings of the SAARC Workshop on Fish Seed Production, 11-12 June 1989. Fisheries Research Institute, Mymensingh, Bangladesh.

Anon, 1986. p.21-49. In Nutritive values of local feedstuffs. Institute of Nutrition and Food Science, Dhaka University, Dhaka, Bangladesh.

A.O.A.C. 1965. Official methods of analysis. Association of Official Agricultural Chemists, 10th ed., Washington D.C., USA. 957 p.

F.F.R.S. 1987. Fish catch statistics of Bangladesh (1984-85). Fisheries Resources Survey System, Department of Fisheries, Dhaka, Bangladesh. 13 p.

F.R.I. 1989. Survey of potential fish feed ingredients of Bangladesh on the basis of their availability and biochemical composition. Research Project Report No.1; Fisheries Research Institute, Mymensingh, Bangladesh. 70 p.

G.O.B. 1986. The Third Five Year Plan, Government of Bangladesh, 1986-1990. Chapter V.C. Fisheries. Dhaka, Bangladesh. 11 p.

G.O.B. 1991. The Fourth Five Year Plan, Government of Bangladesh, 1991-95. Chapter V.C. Fisheries. Dhaka, Bangladesh. 13 p.

Haque, M.Z. and M.M. Hossain. 1191. Progress Report on the development of nursery pond management methods for optimizing production of fry/fingerlings of carps. Manu- script. Fisheries Research Institute, Mymensingh, Bangladesh. 15 p.

Islam M.A. 1989. Fish seed productionin Bangladesh, p 1-12 In Proceedings of the SAARC Workshop on Fish Seed Production, Fisheries Research Institute, Mymensingh, 11-12 June.

Karim,M. 1986. Brackishwater shrimp culture demonstration in Bangladesh, BOBP/REP/ 5, FAO/SIDA,Madras, India. 44 p.

Mahmood, N. 1990. Potential and strategies for brackishwater aquaculture development in Bangladesh. Paper presented at the National Workshop on Aquaculture Strategies in Bangladesh. Bangladesh Agricultural Research Council, Dhaka, Bangladesh.

Mahmood, N. and M.R. Chowdhury. 1989. An overview of shrimp fishery of Bangladesh. Biological aspects. Paper presented at the Workshop on the Environmental Aspects of Agricultural Development and Surface Water Systems. Organized by the Bangladesh Centre for Advanced Studies at the BARC Auditorium, Dhaka, 8-9 November, 1989. Manuscript.

Mazid, M.A. 1992.Aquaculture development in Bangladesh. The Bangladesh Observer, Dhaka. 25 September,1992.

New, M.B. 1987. Feed and feeding of fish and shrimp. ADCP/REP/87/28. FAO. Rome, Italy. 275 p.

Statistical Yearbook of Bangladesh. 1989. Bangladesh Bureau of Statistics, Statistics Division, Ministry of Planning, Dhaka, Bangladesh 365 p.

Zaher,M., M.A. Mazid and S.Gheyasuddin. 1992. Progress Report on development of cost- effective feeds from indigenoud raw materials for fingerlings and adult carps. Manu- script. Fisheries Research Institute, Mymensingh, Bangladesh. 21 p.

AQUAFEEDS AND FEEDING STRATEGIES IN CAMBODIA
S. Nuov¹ and M.C.Nandeesha²

¹ Department of Fisheries, Ministry of Agriculture Phnom Penh, Cambodia

² College of Fisheries, University of Agricultural Sciences Mangalore-575 002, Karnataka, India

NUOV,S. and M.C. NANDEESHA. 1993. Aquafeeds and feeding strategies in Cambodia, p.181-200. In M.B. New, A.G.J. Tacon and I. Csavas (eds.) Farm&-made aquafeeds. Proceedings of the FAO/AADCP Regional Expert Consultation on Farm-Made Aquafeeds, 14-18 December 1992, Bangkok, Thailand. FAO-RAPA/AADCP, Bangkok, Thailand, 434 p.

INTRODUCTION

Cambodia has acquired a special place in history for the sufferings it has undergone in this modern age not only due to the internal conflicts of its own people, but also to its isolation by the international community. These factors have impeded development in almost all spheres, the worst affected being the food sector. Planning for the rehabilitation and reconstruction of Cambodia has been initiated by the international community and it is anticipated that, like other sectors, fisheries will also receive support.

In order to provide a better understanding of the existing situation in Cambodia, some information on its general and agricultural status has been included in this section of the paper.

Agriculture

Cambodia, with an area of 17.64 million ha and a population of 9.01 million, is primarily an agrarian state with 80% of the country's labour force being employed in agricultural sector (Table 1). Nearly 70% of the land area is still reported to be covered by forests and only about 3.63 million ha are under agriculture. Rice is the most important crop cultivated with an area of about 1.9 million ha. The climate and topography have not provided much opportunity for crop diversification from rice to other food or cash crops in most parts of the cultivable land (Table 2). The average yield of paddy is only 1,200 kg/ha.

Although, before the war, rice was an important export item, presently there is a shortage even for internal consumption. In terms of production, agriculture contributes nearly 50% of the GDP (Table 1). Per caput income is estimated to be about US$ 180. Nearly 30% of the families are headed by women because so many men lost their lives during the war. While there is a large trade imbalance, inflation is now running at 190%. These unusual circumstances pose several problems to developmental activities.

Exchange rate (October, 1992): US$ 1.00=Riel 2,050

Sources: various reports and government departments

Source: Department of Agriculture, Phnom Penh

Animal husbandry

Besides agriculture, animal husbandry forms an important component in the Cambodian economy and contributes about 6.6% to the GDP (Table 1). The numbers of livestock, which had declined drastically during the 1970's is now reported to have reached pre-war levels (Table 3). They form an important source of animal protein for the more affluent section of the population, aside from their contribution to animal energy used in agriculture and through the generation of manure. Most of the livestock is of traditional breeds and attempts are now being made to introduce improved varieties and production techniques.

Source: Livestock Department, Phnom Penh

Fisheries

Fish and rice are important staple diets of Cambodians. This food habit has been largely due to the influence of nature as the country is bestowed with a large number of rivers, the Great Lake and a vast amount of flooded areas, which still provide relatively good sources of fish. Although Cambodia has a coastline of 425 km, marine fish has been of less importance in the Cambodian diet as most people prefer freshwater fish. Fish consumption was reported to be as high as 20-25 kg/caput in 1960's, but this declined to about 13 kg/caput/yr in 1991. Total fish production in 1991 was estimated to be about 100,071 t out of which 74,700 t came from the freshwater sector. Figure 1 illustrates the annual variations in freshwater fish production between 1940 and 1991. There is no data available for some years, particularly for the period 1970-1979 as these were years of intensive unrest and organized fishing was probably almost nonexistent. It is widely argued that there is little or no scope to return to the 1957 capture fisheries production level of 130,000 t. At best, with appropriate scientific measures, it may be possible to maintain the current production. Degradation of natural spawning grounds through extensive destruction of flooded forests and a large number of “Pol Pot canals” constructed during the Pol Pot regime have been mostly blamed for the decline in natural catches.

Figure 1. Inland Fish production in Cambodia from 1940 to 1992

Aquaculture

Aquaculture in Cambodia is relatively young as compared to other Asian countries. Although attempts were made during the 1950's to introduce pond fish culture, mainly through introductions of tilapia and Chinese carps, it did not widely catch on, probably due to the abundant availability of captured fish. Bardach (1959) reported that a few farmers in some rubber estates were successful in raising Java tilapia (Oreochromis spp.). It was also reported that the culture of Chinese carps in ponds around Phnom Penh was successful as these fish were popular with the Chinese community. In contrast to pond culture, the culture of fish in cages has been in practice for nearly a century and it is believed that cage culture originated in Cambodia (Chua and Tech 1990). However, this activity almost disappeared during the 1970's and it only started again in the 1980's. Pond culture, mainly of pangasid catfishes, was also started by a few enterprising farmers around Phnom Penh in the 1980's and this activity is slowly expanding to other areas of the country. Freshwater aquaculture production has increased by a factor of four over the years 1984-1991 (Table 4). Feed is the most important cost component (more than 70%) of existing aquaculture systems. Coastal aquaculture activity is yet to be initiated but the recent liberalized policy of the government is expected to attract large investors to this sub-sector.

Source: Department of Fisheries, Phnom Penh

Species cultured

Both indigenous and exotic species are cultured, the former being dominant (Table 5). Among the exotics, tilapia culture is widely attempted by small-scale farmers. Culture of other exotic species is restricted by the availability of fish seed. Among the indigenous groups, pond culture of Pangasius spp. is more prevalent around Phnom Penh city. Cage culture of Pangasius spp. and Channa micropeltes is widely practiced in several parts of the country. Cyprinids are the next important species group cultured in cages. Culture of other species is also seen in some areas, in both cages and ponds, but their contribution to aquaculture production is still very small or, in some cases, is on an experimental basis only by some farmers.

AVAILABILITY OF FEED INGREDIENTS

No published data is available on the accessibility of various types of ingredients. The following information is based on the observations of the authors as well as information provided by various NGO's working in the country.

Plant resources

Since paddy is the most widely cultured crop (Table 2), rice bran of different qualities is an important feed ingredient available throughout the country. Its quantity is estimated to vary between 0.2 and 0.3 million t. Considerable amounts of broken rice are also produced during milling and these are used by some farmers, particularly for the early age groups of fish. Normally two grades of rice bran are obtained during the milling process: first grade and second grade, the former with a considerable percentage of broken rice. Most of the maize produced is exported; little is consumed domestically. Some farmers also use waste corn flour as fish feed when it is cheaply available.

Soybean is used only in the nurseries of fish seed production farms. Although some oilseed crops are also grown, as yet there is no organized oil extraction in the country. Coconut is one of the important plantation crops, but there is no data available on the extent of production.

Farmers engaged in small-scale aquaculture use a variety of wastes available from agricultural crops. Soft aquatic vegetation, like Lemna, Azolla, Hydrilla and morning glory are also utilized as feed for herbivorous and omnivorous fish. A large portion of the water bodies is infested with a variety of aquatic vegetation, the most prevalent being water hyacinth. These aquatic weeds can form a potential source of feed ingredients if suitable techniques for their use could be demonstrated.

Animal resources

Among the animal resources of feed ingredients, fresh fish and/or dried fish are the most commonly used. While there is no organized production of fish meal, most farmers buy the required quantity of fresh fish during the peak fishing season and use it as feed after drying. In the cage culture of both pangasids and snakeheads, the fish are fed with fresh fish throughout the culture period. Fish caught from the wild are classified into three categories based on size: 1 st grade, 2nd grade and 3rd grade. While 1st and 2nd grade fish are generally used for human consumption, 3rd grade fish are utilized for making fish sauce and fish paste. Low quality fish from this group is generally utilized for feeding pangasid catfishes and snakeheads in fresh form or is converted into dried fish for feeding Pangasius in ponds.

The quantity of the different grades of fish harvested during 1989-1991 is presented in Table 6. It appears that, based on a food conversion ratio of 5:1, 70-80% of the 3rd grade fish produced in the country is presently utilized for feeding pangasid catfishes and snakeheads. In addition to fish, waste fish heads, available when dressing fish for fish paste (prahok), are also utilized by the farmers, mainly for feeding pangasids raised in ponds. Other potential sources of animal feeds include poultry offal, blood meal, meat and bone offal, rumen contents, pig offal, the manure of these animals, etc. However, none of these wastes are presently utilized in fish culture, either due to unorganized slaughtering or to difficulties encountered in the collection and transportation of these wastes to the culture sites.

Source: Department of Fisheries, Phnom Penh

It should be noted that most parts of the slaughtered animals still have a greater value as human food. Only pig and cattle manure is utilized by a few farmers in rural areas for pond fertilization. Available information on the proximate composition of a few feed ingredients is presented in Table 7.

* figures represent average of at least two measurements; figures in parentheses indicate rangeof values observed
** feed mixture sampled at Chak Angre Station is a mix of dried fish, rice bran and corn meal

Source: Nandeesha (1991)

ON-FARM FEED MANUFACTURING AND FEEDING STRATEGIES

There is no commercial feed production in Cambodia and most of the feed is farm-made on a daily basis and fed moist. Broadly, the following five types of fish culture systems can be distinguished in the country:

• pond culture of pangasid catfish;

• pond culture of tilapia and silver barb;

• cage culture of pangasid catfish;

• cage culture of snakeheads;

• cage culture of other finfish species.

Some information on the culture practices is available in recent publications (Csavas 1990; Edwards 1991; Nandeesha 1991; Anon. 1992; Nandeesha et al. 1992). In the current paper, the above systems are examined further, from the view point of the feeding strategies adopted by the farmers. In all of the above systems feed constitutes an important component and production is largely governed by its quality and quantity.

Feeding strategies in pond culture of pangasids

The culture of pangasid catfishes, mostly consisting of Pangasius sutchi, is prevalent in ponds located around the capital of the country, Phnom Penh. Culture of pangasids is gaining momentum even in other parts of the country. The ponds generally vary from 600-2,000 m². Fingerlings, weighing more than 50 g, are stocked during the monsoon months (from June to October) at a density of more than 3,000 kg/ha. The stocking density and the weight of fingerlings varies considerably from farmer to farmer. Most ponds have a stagnant water system and possess no drainage facility. They are either filled with rainwater or water is pumped from the nearby lake. Most farmers do not use fertilizers. However, some apply urea at the rate of 5-6 kg/pond of about 800 m² area once in two months to keep the water green. Some farmers engaged in Pangasius culture have latrines overhanging their ponds.

The feeding strategy adopted is largely based on the availability of feed ingredients rather than on any scientific consideration. Fish are fed during the first two months with first quality rice bran. Some farmers also use a 9:1 ratio of broken rice mixed with rice bran during this period. From the third month onwards fish are mostly fed second quality rice bran up to November. Rice bran is always fed in cooked form. The bran, mixed with a small quantity of water, is cooked in an open vessel until a proper dough is obtained. Firewood is generally used for cooking. The cooked dough is allowed to cool and then rolled into small balls and fed to the fish in wet form. Feeding is done during the cool hours of the day, generally in the evening.

With the onset of the fishing season, feeding shifts from rice bran to small fish, as the latter become abundantly and cheaply available. Farmers either buy fresh fish and sun-dry it or buy dried fish and store them for daily feeding. In addition to fish, cut fish heads obtained as a by-product in fish paste manufacturing, are also used by some farmers. Fresh or dried fish is fed generally without any processing but some farmers mix the dried fish with 10-20% rice bran and feed in an uncooked form. The feeding of dried fish continues up to March-April of the following year. Feeding dry fish is drastically reduced or discontinued from April onwards, since farmers believe that the higher water temperatures prevailing later are not conducive to this practice. Rice bran alone, or with a small added quantity of dried fish, continues to be fed until the ponds are harvested.

Feed quantity is not accurately calculated, based on body weight. During the first two months, fish are given feed at approximately 10% of body weight and the quantity is gradually reduced as the fish increase in weight. Towards the end of the culture period the feeding level is about 1.5-2.0%. Fish mortality is a common problem encountered from April onwards due to higher biomass, increased water temperature, the accumulation of organic wastes and lack of water exchange. Unhygienic drying and storage of the fish used for feeding often leads to contamination and spoilage. As can be seen in Table 7, the fat content of both dried fish and fish heads is high.

Fish are harvested after they have attained a weight of more than 1 kg. Significant variability in the weight of fish is common due to variations in the size of fish at stocking. The harvesting period normally coincides with the monsoon, as there is a high market demand for food fish in this period due to the closed fishing season in the natural waters. Production varies widely depending on the intensity of the management practices adopted. Some of the production data provided by farmers indicate that a net production of above 35 t/ha is quite common in well managed ponds. The food conversion ratio varies from 4.5-6:1.

In earlier years farmers tended to stock tilapia together with Pangasius. Presently, the majority of farmers avoid this practice because of the uncontrolled breeding of tilapia and the poor demand for small-sized fish in the market. However, when tilapia are stocked, they are fed with uncooked rice bran broadcast on the pond surface. Some farmers also stock carps with Pangasius, but there is no special feeding practice adopted for cyprinids. These fish appear to derive most of their food through the natural food biomass produced in the pond by the unconsumed food and by faecal fertilization. Non-availability of carp seed and lack of information on appropriate species combination has been the major constraint in the spread of composite culture techniques in Cambodia.

Feeding strategies in cage culture of pangasids

Cage culture of Pangasius spp., consisting largely of P. sutchi and, to a lesser extent, P. larnaudii is common in several parts of Cambodia. A large part of the cage culture activity is concentrated in and around the Great Lake where cage size is generally large (26-900 m³). Some farmers also specialize in the nursery rearing of Pangasius seed collected from rivers. Cages are generally stocked with fish of more than 100 g at a stocking rate of 4-12 kg/m³. Fish are usually fed trash fish when it is available. A large quantity of small fish is spread on the cage surface and allowed to rot because farmers believe that Pangasius feed voraciously on spoiled fish. Under such circumstances, fish are normally fed only once every two or three days.

When trash fish is not available, cooked rice bran is used (Figures 2 and 3). A pelletizing machine is installed on some of the larger cage sites.

Figure 2. Cooking feed for cage cultured pangasid catfish

Figure 3. Hand-feeding pangasid catfish in a boat-shaped floating cage

Cooked rice bran is pressed through a mincer to roll it into small balls which are allowed to fall directly into the cage (Figure 4). When even rice bran is not available, aquatic vegetation, consisting mainly of Lemna, Azolla and morning glory, is used as feed. Aquatic vegetation is only used as a last resort, since farmers have experienced poor growth rate in fish fed continuously with plant materials over a long period.

35-60 kg/m³ of fish is produced in 8-12 months. The food conversion ratio is reported to be 4-6:1. Farmers' instinct tells them that fish need to be fed more than 4 kg feed for each kilogramme of fish produced and they tend to achieve this ratio by providing more feed during the glut season. Fish mortality during the summer months, particularly during April and May, is a common phenomenon due to high temperatures and reduced water exchange, coupled with the deterioration of water quality because of the discharge of wastes from the cages, which are often crowded in one locality.

Figure 4. Locally manufactured feeding machine for large catfish cages

Feeding strategies in snakehead culture

Two species of snakehead, namely Channa micropeltes and C. striatus, are cultured in cages. The former is the most popular due to its faster growth. Unlike the culture of pangasids, snakehead rearing is entirely dependent on an animal source of protein, namely trash fish. Cages used for snakehead culture are smaller (7-211 m³). Fish are normally stocked during the monsoon months (June to August) with fish of more than 50 g at 20-30 kg/m³. Fresh trash fish caught from the rivers is fed daily, normally ad libitum. When trash fish is unavailable, the snakehead are starved for periods of up to several weeks. Larger trash fish are chopped before feeding. Some farmers also use suspended feeding trays within the cage.

The feed conversion rate (FCR) is 4.5-6:1. Again farmers make the general assumption that a minimum of 4 kg of trash fish is needed to produce 1 kg of marketable fish. During periods of trash fish glut farmers feed their fish more than once a day to reach these levels. Occasionally, some farmers feed rats captured from paddy fields, particularly when trash fish becomes scarce. Recently, the culture of Pangasius along with snakehead but in a separate cage, is gaining popularity; this utilizes leftover trash fish from the snakehead cages.

Fish achieve more than one kilogramme in 8 to 12 months. Growth is dependent on the availability of feed and stocking density. Mortality during the summer months is the most common problem due to high water temperatures and reduced water exchange. Most cages are in crowded conditions resulting in severe water pollution due to the discharge of wastes.

Feeding strategies in pond culture of tilapia and silver barb

Fish culture has been initiated during the last 3-4 years in ponds constructed under the Food for Work programme of UNICEF and the World Food Programme. Tilapia and/or silver barb are generally stocked during the monsoon, when ponds can be filled. For various reasons, pond culture has not been uniformly successful. Long-term severe water turbidity which inhibits the level of natural productivity is experienced. Despite this, some farmers have been able to achieve production rates of 60-100 kg in ponds of less than 300 m².

The successful farmers, besides fertilizing the ponds regularly with organic manure, feed the fish with rice bran. The quantity increases gradually, as the fish grow, from 0.5 kg/day to 3.0 kg/day. No definite feeding ratios are adopted. The quantity provided is mainly governed by the availability and cost of rice bran. In addition to rice bran, fish are also sometimes fed corn meal, termites, red ants and aquatic vegetation. Almost all the fish pond owners also rear pigs; these are usually given a higher priority for rice bran than fish.

Feeding strategies in the culture of other species

Besides pangasid catfishes and snakehead, Puntius gonionotus, Puntius altus and Leptobarbus hoeveni are cultured in many cages. Small cages (50 m³) are stocked with a total of 8-10 kg/m³ (average weight 3-5 g) of cyprinids, and reared for 8-10 months. Rice bran is commonly used as feed, as well as aquatic vegetation and kitchen wastes. 40-50 kg/m³ is generally obtained.

Clarias batrachus, Cirrihinus microlepis and Notopterus chitala are also cultured on a small scale, largely as scavenger species in Pangasius cages. Attempts to culture sand goby (Oxyeleotris marmorata), have not been successful. Currently, cages are used to hold larger sand gobies caught from rivers until they are exported. Even during this short holding period, heavy mortality is common.

Alternating pen/cage culture is another system, seen only in the two northeastern provinces in the Great Lake. As the Great Lake seasonally fluctuates farmers use pens during the dry season and transfer the fish to cages during the wet season when the water level is higher. Fish are heavily fed with trash fish in the pens, and with rice bran in the cages.

Attempts to rear climbing perch (Anabas testudineus) and a few indigenous cyprinids in ponds have also been made. Although exotics such as common carp (Cyprinus carpio), silver carp (Hypopthalmichthys molitrix), grass carp (Ctenopharyngodon idella) and bighead carp (Aristichthys nobilis) are in demand, due to the lack of seed of these species and a poor extension system to demonstrate their suitability in culture systems, their culture is limited. In those seed farms which exist fish are fed mainly with rice bran; in addition ponds are periodically fertilized. Rice-fish culture is also being tried on a small scale by some farmers, but is not yet established.

MAJOR INSTITUTIONS INVOLVED IN AQUAFEED RESEARCH AND DEVELOPMENT

The country lost the majority of its educated manpower during the Pol Pot regime. The Fisheries Institute, which used to offer a degree course in fisheries, was also destroyed. With the surviving trained personnel, fisheries development programmes restarted only in 1980. A large number of untrained people had to be recruited to manage the fisheries sector. The Fisheries Institute was restarted, with the assistance of the Soviet Union, in 1984 to provide trained manpower. Presently, a four and a half year degree programme in fisheries is offered by the Chamcar Daung Institute of Agriculture and a three year diploma course in fisheries is provided by the Prek Leap Agricultural School. At the latter some in-service training is also offered.

Although some aspects of fish nutrition are taught to students at these two schools, they have not yet started a research programme. A National Freshwater Fisheries Research Station has been established by the Department of Fisheries in Phnom Penh to conduct research on various aspects of fisheries, including nutrition. However, no major research activity has begun yet due to the lack of trained manpower and financial resources. More recently PADEK, a non-governmental organization, has initiated an aquaculture development programme, which includes a major component on fish nutrition and breeding.

CURRENT NATIONAL REGULATIONS

The Department of Fisheries has complete control over fishing in natural waters. The water bodies are divided into fishing lots which are auctioned annually for the fishing season, which begins in October and ends in May. Hence, trash fish is available only during this season. During the closed season, fishermen resort to illegal fishing to obtain feed for cultured snakeheads. Some attempts have been made by the Department of Fisheries to regulate the number of snakehead cages to avoid this practice. Besides this, there are no regulations with regard to the manufacture or quality control of fish feeds.

CURRENT PROBLEMS AND CONSTRAINTS

Existing feeding techniques result in a considerable wastage of feed, even though the supply of feed is often inadequate. The availability of trash fish is constantly declining due to the increasing demand for all varieties of fish for human food. Overcrowding of cages at some localities and consequent impairment of the water quality has been causing considerable production losses. In common with other parts of the region, the nutritional requirements of pond-grown fish in the presence of natural food are unknown.

The variety and quantity of raw materials available as aquafeed ingredients is limited due to competing demand. Most animal “waste” products are still used for human consumption; very little is left over for aquaculture after the animal husbandry sector has taken first pick. Furthermore, due to poor transportation facilities, ingredients are not always available at the places and times when they are required. Even simple machines for feed processing and manufacturing are not easily available.

There is no established credit system. As a result, many farmers borrow money at a high interest rate; most of their profits go to the moneylenders. Finally, due to the lack of trained manpower and resources, there has been no progress in research and development.

TRENDS IN AQUAFEED MANUFACTURING AND USE

Trash fish availability will become a major constraint and it is likely that omnivorous and herbivorous species will become more popular than carnivorous species. Research will then be required, to evolve cost-effective diets and feeding strategies. Research must concentrate on deriving the maximum benefit from the natural food produced in the system, because of the national shortage of feed ingredients. Since Cambodia is heading towards a free market economy, it is likely that foreign feed companies will enter the market to develop the aquaculture of valuable fish species for export. Development of on-farm feed manufacturing and feeding strategies is likely to be priority areas of future research. The Department of Fisheries has no definite plans as yet; planning must also depend on external assistance, since expertise is not readily available within the country.

CONCLUSIONS

Although international isolation has contributed to the slow growth of aquaculture in Cambodia, enterprising farmers have made significant progress with some species. Non-availability or shortages of fish in markets, particularly in areas far from rivers, is quite common. Even those living close to rivers do not get abundant supplies of fish throughout the year. A recent study conducted by the Mekong Committee (Anon. 1992) indicated that even to meet the minimum human nutritional requirements in animal food, the present fish production of 100,000 t has to be doubled.

Since there is very little scope to increase fish production from capture fisheries, aquaculture must fill this gap. As fish is popular among Cambodians, the transfer of appropriate technologies would assist the expansion of aquaculture. Fish culture is already recognized by successful farmers as more profitable than agriculture, due to its higher rate of return. In view of the scope for expansion both in commercial aquaculture and family level feed production systems, there is an urgent need to address the following priority fish feeding problems.

Ingredient availability

There is a paucity of information on the type, quantity, quality, seasonality and cost of available feed ingredients. This information is essential to formulate a good aquafeed development programme. A detailed survey is therefore essential to prepare a national feed map using the guidelines suggested by Tacon et al. 1987.

Feed management

Existing cage culture practices require closer examination. With the increasing demand for fish, trash fish availability will be reduced. It is therefore necessary to find a substitute diet for snakeheads. Existing feeding practices for pangasids result in considerable wastage of food. The establishment of a factory to make fish meal available at competitive prices throughout the year would help to solve this problem. Since farmers are already familiar with on-farm feed manufacturing the development of cost-effective feed formulae, based on those ingredients which are locally available, would help the industry. The possibility of using some of the cheap marine fish for the production of fish meal should also be considered.

The feeding practices adopted in the pond culture of pangasid catfishes is also dependent on the seasonal availability of feed ingredients and results in considerable wastage. The provision of balanced diets throughout the year would enable farmers to increase production at reduced cost.

Natural food

There is also scope to increase the production of herbivorous and omnivorous fish for culture in cages through improvements in their diets and feeding strategies. Presently, farmers feed mainly rice bran, obtaining moderately good production levels. Natural food inputs are also significant. Quantifying the contribution of natural food organisms would aid the development of cost-effective diets.

The development of aquafeeds and feeding strategies based on ingredients which are easily accessible to farmers and the level to which the nutritional requirements of fish could be met from natural food would pave the way for further expansion of aquaculture (New 1989; De Silva and Davy 1992; Tacon 1992).

Unconventional ingredients

The pond culture of other species also faces shortages of suitable feed or ingredients. While rice bran continues to be an important feed ingredient in rural areas, competition from pig raising often results in its scarcity for aquaculture. Some farmers collect termites and red ants and feed them to fish and it could be worthwhile studying cost effective methods of culturing such promising live food organisms for use as fish feed. Aquatic and terrestrial vegetation may provide good sources of feed for rural aquaculture. The development and/or introduction of simple technologies to culture aquatic vegetation would also help the farmers.

Research and development

There appears to be a number of indigenous fish species suitable for culture in both cages and ponds. Screening such species and studying their nutritional requirements, both in the absence and presence of natural food, should be a long term programme for investigation.

Shrimp culture is reported to have commenced on a small scale with the participation of some foreign companies. Cambodia will thus gain from the experience of other countries in the region in both shrimp culture and the development of a shrimp feed industry.

Financial and human resources

Due to inadequate financial resources and trained manpower there has been no progress in research work. It is urgent to train people in all aspects of aquaculture, including fish nutrition and diet development. External support and expertise is necessary until Cambodia is able to support itself.

LIST OF REFERENCES

Anon. 1992. Fisheries in the lower Mekong basin (Review of the fishery sector in the lower Mekong basin) - Main report. Interim Committee for Coordination of Investigations of the lower Mekong basin, Mekong Secretariat, Bangkok. 92 p.

Bardach, J. 1959. Report on the fisheries in Cambodia. USOM/ Cambodia, Phnom Penh, Cambodia. 80 p.

De Silva, S.S. and F.B. Davy. 1992. Fish nutrition research for semi-intensive culture systems in Asia. Asian Fisheries Science 5:129-144.

Chua, T.E. and T. Tech. 1990. Aquaculture in Asia - quo vadis? p. 13-30. In M.M. Joseph (ed.) Aquaculture in Asia. Asian Fisheries Society, Indian Branch, Mangalore, India.

Csavas, I. 1990. Back to office report of the fisheries specialist of the Interim Mekong Committee's fact finding mission to Cambodia, 1-12 November, 1990. 14 p.

Edwards, P. 1991. Report on a trip to Cambodia. Asian Institute of Technology, Bangkok, Thailand. 63 p.

Nandeesha, M.C. 1991. A report on aquaculture in Cambodia - status, constraints and opportunities. CIDSE and PADEK, Phnom Penh, Cambodia. 85 p.

Nandeesha, M.C., H.P.C. Shetty and T.S. Tana. 1992. Freshwater aquaculture in Cambodia. Paper presented at the Third Asian Fisheries Forum, 26-30 October 1992, Singapore.

New, M.B. 1989. Formulated aquaculture feeds in Asia : some thoughts on comparative economics, industrial potential, problems and research needs in relation to the small-scale farmer, p. 19-30. In Report of the Workshop on Shrimp and Finfish Feed Development, 25-29 October, Johor Bahru, Malaysia. ASEAN/UNDP/FAO Regional Small-Scale Coastal Fisheries Development Project, Manila, Philippines.

Tacon, A.G.J. 1992. Aquaculture nutrition and feeding in developing countries: a practical approach to research and development. Paper presented at the IVth International Symposium on Nutrition and Feeding in Fish, 24-27 June 1992, Biarritz, France.

Tacon, A.G.J., G. Maciocci and J.E. Vinatea. 1987. National agricultural feed surveys for aquaculture planning and development in Latin America and the Caribbean. 1. Guidelines. FAO Project GCP/RLA/075/ITA, Field Document No. 1/E, Brasilia, Brazil. 11 p.

AQUAFEEDS AND FEEDING STRATEGIES IN CHINA
Wang Ping

Division of Science and Technology, Bureau of Aquatic Products, Ministry of Agriculture 11 Nongzhanguan Nanli, Beijing 10026 People's Republic of China

WANG.P. 1993. Aquafeeds and feeding strategies in China, p. 201-212. In M.B. New, A.G.J. Tacon and I. Csavas (eds.) Farm-made Aquafeeds. Proceedings of the FAO/ AADCP Regional Expert Consultation on Farm-Made Aquafeeds, 14-18 December 1992, Bangkok, Thailand. FAO-RAPA/AADCP, Bangkok, Thailand, 434 p.

INTRODUCTION

China is located in the northwestern part of the Pacific, covering about 40 latitudes from the tropical through the temperate zone. It faces the Bohai, Yellow, East China, and South China Seas as well as the Pacific in the eastern coast of Taiwan. The coastline stretches from the mouth of the Yalu River, Liaoning Province, to the mouth of Beilun River of Guangsi Zhuang Autonomous Region, a distance of about 3.200 km. This long curved coastline forms many excellent bays and harbours which provide tremendous potential for fish culture. China also has 20 million ha of inland water resources. Rivers, lakes, reservoirs and ponds can be found all over the country; 5.8 million ha is suitable for aquaculture according to current technology. Moreover, there is plenty of low lying and waste land which can be excavated for fish farming.

China is abundant in aquatic organisms. There are more than 1,500 species of marine finfish and 800 from freshwater. Of these, roughly fifty are of high economic value. In addition to finfish there are thousands of valuable crustaceans, molluscs, seaweeds and other aquatic organisms.

China has a long aquaculture history and plays a very important role in the global fish farming industry. Some 2,400 years ago Fan Li, the premier of Yue State, wrote the earliest book on pisciculture. Now, China's aquaculture production is the greatest in the world, contributing 6.53 million tons, more than 50% of aquaculture production worldwide. It is well-known that China is the first country to have developed techniques for the artificial breeding of carps which made fish farming bloom not only in China but also in the whole world. China's freshwater fish fry production in 1991 was 157.8 billion, 142.1 billion of which came from artificial breeding. The area under aquaculture production was 4.3 million ha. Total fisheries production in 1991 was 13.5 million t, of which aquaculture contributed 6.5 million t (Table 1 and Figure 1). According to the State Plan, fisheries production will reach 18 million t in the year 2000; 70% of the output will have to come from fish farming due to the limitation of offshore fisheries resources.

Since 1979, Chinese government policy has been to emphasize and encourage the protection of natural fisheries resources and to develop aquaculture to meet the increasing demand, both domestic and international, for aquatic products. Aquaculture production and area has increased greatly. Now there are 30 different species cultured in China, the most important being freshwater fish, including silver, bighead, common, and crucian carps, Chinese freshwater bream (Wuchang fish), mud carp, tilapia and black carp. These species contribute more than 90% of the total aquaculture output (Table 2). Coastal aquaculture production in 1989 (Table 3) was 1.6 million tons, of which 12% were crustaceans and 67% molluscs (Figure 2).

Shrimp culture has bloomed since the 1980's and has become one of the success stories of aquaculture, not only in China but also in the whole globe. By 1988 the value of China's cultured shrimp exports had risen to US$ 595 million per year (Table 4). Now, due to the land limitation and environmental problems. the government has shifted attention, from expanding the area of arable land used for aquaculture ponds, to encouraging fish farmers to fully utilize the ponds they have. Increasing the yield per unit area by using high yielding or intensive culture techniques and formulated feeds, and developing low-lying and waste land for aquaculture are promoted.

Figure 1. Aquatic production in China from 1950 to 1991

Feed manufacturing is one of the fastest developing agro-industries in China. According to 1991 national statistics, there are 9,154 feed mills in China which have a designed production capacity of 1 t/hr or more. Total feed production was 36 million t. Of this, formulated or compound feeds constituted 35 million t, 589,000 t were concentrates and 298,000 t feed premixes. Of the formulated feed, swine feeds contributed 44% and poultry feeds 48%, while aquafeeds only accounted for 3% (Table 5 and Figure 3). Guangdong Province produced the most formulated feed (4 million t), followed by Shandong Province with 3.21 million t and Jiangsu with 2.58 million t. Hunan Province is the primary producer of concentrates with 150,000 t, followed by Shaanxi Province. Sichuang Province produced 73,000 t of feed premixes, placing it first in the country, followed by Tianjin and Shanghai.

* includes bighead carp, which were not reported seperately in 1990
** includes freshwater prawns, river crabs, freshwater pearl oysters and other cultured species

* data are given according to Chinese standards, e.g. seaweeds are measured in dry weightand some of the molluscs with their shells off

The structure of China's feed industry is quite complicated (Figure 4). Feed mills belong to various Ministries or so called “systems”. Two of the most important systems, which control feed ingredients and production, are the Ministry of Commerce and the Ministry of Agriculture. The Ministry of Commerce (and the companies and enterprises under its control) is the main channel for grain processing and marketing. Feed production from its feed mills is usually for commercial use. The Ministry of Agriculture controls grain production and feed consumers, so part of its production is for sale, and part is for its own farms' use. Feed mills under these two “systems” account for more than 93% of Chinese feed mills.

Figure 2. Coastal aquaculture production in China in 1980 and 1989

Figure 3. Formulated feed production in China in 1991

Figure 4. Structure of feed milling industry in China in 1991 (mills over 1 t/hour capacity)

AVAILABILITY OF FEED INGREDIENTS

Feed ingredients used in China vary according to the target animal species, to feed mill locations and to the availability of products and by-products. The main animal protein resources for shrimp and marine finfish are fish meal (either produced in China or imported from South America) and yeast. Bone meal and other animal processing wastes are mainly used for freshwater fish culture. Due to the limited availability of animal proteins, plant proteins also play a very important role in aquafeeds, especially for freshwater fish. The traditional plant proteins used in aquafeeds are soybean meal or cake, rapeseed cake and cottonseed cake. Scientists are working on the replacement of fish meal in shrimp feeds by plant proteins, in order to reduce feed costs, and they have got quite exciting results. With the rapid growth of aquaculture, feed protein resources, especially high quality animal proteins, are in great demand. Total fish meal utilization in 1991 was 706,542 t, of which domestic production was only 74,000 t, accounting for 10% of the total (Table 6). 633,000 t were imported from other countries, mainly from South America, at a cost of US$ 313 million.

China's annual oil cake production is about 10 million t. Soybean cake contributes more than 60% of the total, cottonseed cake accounting for 30% and rapeseed cake 10%. For economic reasons, more oil cake has been used for shrimp and fish feeds, especially soybean cake. In the southern part of China, rapeseed cake and cottonseed cake are the main plant proteins used but in the northern part of the country it is soybean cake. Cottonseed cake and rapeseed cake are said to be toxic to livestock and other kinds of terrestrial animals but, according to research results, aquatic animals are less sensitive than other livestock. In the southern part of China fish farmers spread crushed rapeseed or cottonseed cake into the fish ponds as supplementary feed for fish in integrated farming systems. As commonly used compound feed ingredients in China, rapeseed or cottonseed cakes account for more than 60% of feed formulae and are thus the principal protein resource.

AQUAFEED MANUFACTURING INDUSTRY

Aquafeed manufacturing is a newly emerging branch of the feed industry. Feed has been used for aquaculture starting from the early 1980's but has been greatly promoted in the last ten years. Through the development of aquaculture, especially the extension of intensive fish and shrimp farming and the new fish culture techniques of cage/pen culture, aquafeeed production has become an independent arm of the feed industry. According to statistics which are incomplete, due to the complicated structure of the industry noted above, there were more than 1,600 aquafeed mills by 1991, with a total designed single-shift production capacity of nearly 2 million t, and an actual production of about 700,000 t of aquafeed (Table 7). Of these, two hundred were shrimp feed mills with 700,000 t of capacity, twenty produced eel feed and nearly 1,400 produced feeds for freshwater fish. In addition, there were eleven aquafeed additive mills and eight micro-pellet mills. Currently, it is estimated that 15% of the total feeds used in aquaculture are formulated commercial feeds. State planning aims to increase this to 40% by 1995; this means an increase to about 3.5 million t of formulated aquafeed per year.

The aquafeed industry has evolved from producing single feeds for a few cultured species to producing many types of feeds, of different sizes and nutrient composition, to meet the special requirements of the different developmental stages of grass carp, common carp, Chinese freshwater bream, tilapia, rainbow trout, eel, shrimp, abalone, etc. Shrimp feed production has increased very quickly, due to the high market value of shrimp. Of total formulated aquafeed production in 1991, shrimp feed constituted 300,000 t (43%). China's eel feed market used to be monopolized by foreign feed mills but, in 1991, China

produced 20,000 t of eel feed itself, accounting for 3% of the total. Freshwater fish culture accounts for more than 70% of total aquaculture output but, at 380,000 t, only 54% of the total formulated aquafeed output.

Shrimp and eel feed together contribute over 46% of the total formulated feed production because of the high market value of these species groups. Traditional fish culture methods are generally employed in freshwater fish farming, even though the government has put great emphasis on the expanded use of formulated feeds. Due to the relatively low value of the aquaculture output, the use of aquafeeds for freshwater fish is mainly confined to farms employing intensive methods of fish production. Currently, feed costs usually contribute more than 60% of total Chinese production costs in shrimp or freshwater fish culture.

Formulated feeds are generally used on commercial fish and shrimp production sites where there are always some large-scale feed mills nearby. These feed mills are usually owned by state and joint ventures and have good facilities and quality control systems. They purchase feed ingredients, additives and feed premixes from both domestic and international markets. In general, their feed formulation is based upon research results and the quality is good. However, the cost of their feeds is relatively higher than that of farm-made feeds. In freshwater fish production complete formulated feeds are used only in rainbow trout and eel farms, which are mainly intensive monoculture systems with running water and very high stocking densities. In these cases the fish can only get their required nutrients from the feed presented.

Shrimp feed is a special case, because most Chinese shrimp farms practice semi-intensive culture methods. Formulated feeds and unprocessed ingredients, like molluscs and trash fish, are fed to the shrimp ponds. Until now,

there are no shrimp farms that use formulated feeds alone. Compared to fish feed, shrimp feed is expensive, about US$ 0.78/kg with an average conversion rate of 3:1.

Feed additives and premixes for use in feeds produced for shrimp, marine finfish, eels and other cultured aquatic organisms are usually imported from other countries. According to customs statistics, China imported 981 t of additives in 1991, valued at US$2.25 million. There are no special additives for aquaculture; most of the large-scale aquafeed mills are using additives prepared for livestock. It is said that Roche has developed premixes and additives specially for aquafeed but these have not yet been used in China. The small-scale feed mills and on-farm feed manufacturing workshops generally do not use additives or vitamins for freshwater fish but some add some commercially available vitamins manufactured for humans.

ON-FARM FEED FORMULATION AND MANUFACTURING

Small-scale feed mills or feed manufacturing workshops on fish farms are very simple, typically having a single grinder and one pelleting machine. Such feed mills usually use the grains and grain processing wastes which are locally available, such as wheat or rice bran, mixed with small amounts of fish meal and oil cakes. Their formulation commonly follows the advice of local fisheries extension agents and is based on the availability of feed ingredients in the vicinity. The feeds coming from these feed mills are quite cheap, about US$ 0.29/kg. Although they do not supply all the nutrient requirements, they are suitable for extensive or semi-intensive fish culture to supplement from the natural food produced in the pond. Since polyculture systems are used, it is difficult to calculate feed conversion rates but, in general, they are about 2.5:1.

MAJOR INSTITUTIONS INVOLVED IN AQUAFEED

RESEARCH AND DEVELOPMENT

The Chinese government has paid great attention to fish and shrimp nutrition and to feed manufacturing for a long time. According to estimates, there are more than 100 scientists working on fish and shrimp nutrition research, and on the development of feed formulation and manufacturing for aquafeeds alone. Most fisheries research institutes are actively involved in fish and shrimp nutrition research and development projects, depending on local requirements and environments.

The Heilongjiang Fisheries Research Institute is located in the north of China where water temperatures are quite low. Its research projects on fish nutrition concentrate on rainbow trout. The Institute has published many papers on the results of its research work and has also developed and produced rainbow trout feed for fish farmers. The Yellow Sea Fisheries Research Institute is located on the coast of Shandong Province. Attention is focused on the nutritional requirements of, and feeds for, shrimp. Its research results are now the foundation of shrimp feed formulation in China and have been widely adopted by the shrimp feed manufacturing industry.

The East China Sea Fisheries Research Institute is in Shanghai, in one of the most developed areas of China. Its research and development projects are aimed not only at shrimp feed but also at eel feeds. The pelleted eel feeds developed by this institute are very well received by eel farmers and have greatly promoted the development of a domestic eel feed industry. At the same time, the Institute also works on the use of plant proteins to substitute for fish meal in aquafeeds in order to decrease their cost. The South China Sea Fisheries Research Institute also works on shrimp feeds but concentrates mainly on tropical species and marine finfish. The Yangtze River Fisheries Research Institute has many qualified researchers who are involved in freshwater fish nutrition and feed formulation. Their results are commonly used in manufacturing compound feeds for grass carp. Researchers at the Shanghai Fisheries University are working on the nutrition of black carp, having studied the amino acid and fatty acid requirements of this species. Based on their research, feeds for black carp have been manufactured.

The Beijing Fisheries Research Institute is very successful in common carp feed formulation and manufacturing. With the assistance of the American Soybean Association, it has developed techniques to replace fish meal by using extruded soybean meal. Based on this technique, feed costs can be greatly reduced. Common carp is the favorite species of the North which is also the production base of soyabean. Currently, in the northern part of China, many feed mills are using the formulation and feed additives developed in the Beijing Fisheries Research Institute to produce common carp feed for fish farmers.

Besides the above mentioned institutions, the Shanghai Fisheries Machinery and Instrument Institute, a specialized institute working on fisheries machinery development and manufacturing, includes work on aquaculture equipment. Monitoring the needs of developing aquaculture for feeds, it designs and produces various feed pelleting machines and extruders for fish farmers. The Institute has developed a new kind of shrimp feed by using a special machine; the resultant feed sinks to the pond bottom and floats to the water surface later. This new feed promotes good water management because, when uneaten feed floats to the water surface, farmers can reduce their feeding rate thus both improving water quality and decreasing feed wastage. This research result, however, is not yet utilized in commercial shrimp feed mills.

CURRENT PROBLEMS AND CONSTRAINTS

China's aquafeed industry has developed very fast, gained much experience and learnt many lessons in the past ten years. Compared to the Chinese livestock feed industry, the aquafeed industry has a long way to go to meet the demands of a rapidly expanding aquaculture production. The problems and constraints are two-fold, from both within and outside the industry.

First of all, feed processing capacity is limited and the utilization rate of existing facilities is low. In 1991, the single shift aquafeed production capacity was 2 million tons, which accounted for only 6% of the country's total formulated animal feed production capacity. Actual aquafeed production was less than 3% of the total. Only 15% of the total volume of aquafeeds used in fish culture were formulated feeds. Assuming double-shift operation, the utilization rate of the built-in capacity was less than 28%.

The aquafeed supply structure is not ideal. Until now, feeds are generally available for the grow-out phase of fish and shrimp culture, but the production of feeds for younger age groups, especially for larvae and fingerlings, has only just begun. The domestic production base for feed premixes, binders and other additives, as well as for concentrates, is quite weak. currently falling behind requirements.

Domestic animal protein supply is inadequate to meet the requirements of aquaculture development. The import of fish meal has been steadily increasing over several years, and has caused increasing feed costs and required large amounts of foreign currency exchange.

Due to the lack of scientific management, the quality of the feeds produced is often poor. Except for some large-scale feed mills and joint ventures, most feed mills do not have trained personnel to provide professional management.