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Sutandar Zainal
Department of Fisheries, Padjadjaran University, Bandung, Indonesia
Pepen Effendi
formerly at Saguling and Cirata reservoirs, Indonesia


Commercial net-cage aquaculture in Indonesia was initially developed in the Saguling and Cirata hydropower reservoirs, West Java, as an option to the resettlement programme for the villagers affected by the project. By 1996, more than 25,000 units of net cages were installed in Cirata, producing 42,750 t of fish/year, and about 4400 units were producing 4000 t/year in Saguling reservoir. Large-scale business and better welfare achieved in the surrounding project area indicates the success of the option. The results are accelerated by the extension programme supported by the West Java Hydropower Project and implemented by the related agencies, research institutions, university, Fisheries Service, local government and the target people. Problems associated with the extension programme are related to the weakness of implementation of regulations, decrease in profit margins, degradation of the reservoir water quality and constraints in technology and management. Advanced extension programmes in net-cage aquaculture are required to improve fish farmers' technical and management skills. Stricter controls are also needed to maintain the good water quality in reservoirs with net-cage culture.


Net-cage aquaculture has been practised in Indonesia for a long time. In West Java, fish farmers keep fish in bamboo cages set in a shallow river and the fish are cultivated by utilising other aquatic organisms or detritus. In Kalimantan, fish captured in a river are kept in bamboo cages, before being sold in the market. In Toba Lake, North Sumatra, where freshwater fish is a popular food for traditional and ceremonial events, local people keep the fish in various types of cages and feed them with plant leaves. Similar types of cages are also found in other places throughout Indonesia. This traditional system uses a simple method of cultivation where, with no other production inputs and technology, the fish growth is wholly dependent on the fertility of the water body where the cages are placed.


Intensive commercial net-cage aquaculture was first developed in Lake Lido, West Java, in the 1970s, but a large-scale system was primarily developed in Saguling and Cirata hydropower reservoirs, West Java, starting in 1986. The idea of net-cage aquaculture is one of the options for providing employment for people displaced by the reservoir. Such a scheme, realised by the West Java Hydropower Project, was based on recommendations made by the Institute of Ecology, and included the resettlement of 1500 families each, from Saguling and Cirata, respectively.

Another incentive for aquaculture was that land-based fish culture was well developed and traditionally familiar to the local people of the eastern part of West Java. The current fish production is still a low 17 kg per person per year, but it is expected to reach 27 g/person/year. It means that additional 670,000 t/yr of fish should be produced (West Java Fisheries Service, 1988).

Saguling and Cirata reservoirs are established primarily for hy dropower, and their design and operation criteria are specified for this purpose. The projects are located in hills dominated by dry farmlands and upland forest vegetation. The resettled persons are predominantly farmers, with no experience in aquaculture. Considering this, the net-cage aquaculture development considerations were already included in the planning stage of the resettlement scheme. These included biotechnological aspects of reservoir aquaculture as well as socio-economic and psychological aspects. During the implementation phase field trials, training of affected villagers, and extension in reservoir aquaculture technology and management were also included.

Development of net-cage aquaculture in the project reservoir aimed at the creation of a new job opportunity for the resettled villagers, and at reducing the population pressure on the land. This was expected to contribute to maintaining or improving social welfare of the affected villagers, as well as to increase the local and regional income.

On the other hand, it is important to maintain the fishery sustainability in reservoirs, which is greatly related to the reliability of electric supply system of the hydropower plants. The development of net-cage culture was also expected to contribute to the feeling by fish farmers that they are an important part of the reservoir and hence to increase their awareness of the need to protect the reservoir environment against undesirable impacts, including the deterioration of water quality.

Intensive field observations were organised by the Saguling and Cirata Fisheries Management Unit and the hydropower plant, from the beginning of the programme up to the implementation of extension for net-cage aquaculture in the reservoirs. Data presented here are also assembled from the quarterly reports on water quality, technical reports prepared by the related agencies and publications from the West Java Fisheries Service, and research institutions. Results of the recent field trials are also included.


As the constraints on environment and the complications arising from the resettlement process existed even during the early stages of the project, the planning for a holistic and systematic extension programme of net-cage aquaculture was also initiated early. Attention was paid especially to the following:

Considering the constraints and complications, in order to achieve the objectives of this resettlement option, and agri-aquaculture development plan was designed by the related institutions, i.e. the West Java Hydropower Project, Provincial Resettlement Co-ordinating Board, and West Java Fisheries Service, prior to the impoundment of the two reservoirs. The plan recommended the establishment of a Fisheries Management Unit to manage the development of aquaculture in the reservoir, and the collaboration of the project with universities, research institutes, fisheries agencies and related institutions to develop studies, field trials and training in reservoir aquaculture. The cost of the development plan was allocated from the total project budget.

Studies and field trials as well as training in net-cage aquaculture were carried out at the already existing and comparable reservoirs. In the three years prior to the impoundment, ten extension activities were carried out, including studies, trials and training in reservoir aquaculture, conducted by the West Java Fisheries Services, Research Institute and the Research Institute for Inland Fisheries. In each activity 10 to 15 people participated. After impoundment, another seven field trials and training sessions were implemented by the same institutions and by the Bank of Indonesia.

To assist the Fisheries Management Unit of Saguling and Cirata reservoirs and to design a management plan for the development of aquaculture in the reservoirs, especially for the affected families, the World Bank project funded a consulting service programme in co-operation with the Institute of Ecology (IOE) and the International Center for Living Aquatic Resources Management (ICLARM) during 1986–1989. The programme conducted interdisciplinary studies, trials and training for the affected families and the staff of the Fisheries Management Unit and the Hydropower Project (Sutandar et al., 1989).

The total of affected people trained during the pre-impoundment was 157, while 845 people attended extension programmes. After impoundment, IOE and ICLARM organised an intensive training programme for 242 affected people and an extension programme which was attended by 1716 people (PLN, 1990). As a follow-up to the IOE and ICLARM programme, other related institutions and private agencies conducted a number of field trials and training activities. However, the intensity and magnitude were mostly limited to feeding trials and fish species identification.

As the demand for Nile tilapia (Oreochromis niloticus) increases, private agencies have been carrying out studies on this species in Cirata. The extension activities have included the latest innovations in net-cage aquaculture technology, use of quality seed, use of the genetical improved tilapia, use of floating feed, application of double or triple layer nets, and metal framed cages and fibreglass drums instead of traditional bamboo cages and drums. This has been done with the objective of maximising the profit from net-cage aquaculture.

There has been good interaction among the target families, hydropower project management, fisheries agencies, local government, universities, research institutes and extension workers, as well as successful technology transfer, training, extension and supervision. The success of the implementation of the extension programme was indicated by the development of net-cage aquaculture in Saguling and Cirata reservoirs, i.e. number of netcage units, total people involved in the business, fish production, and a better income and welfare of the people and the area.


As a result of an integrated plan and intensive extension programme, development of net-cage aquaculture in Saguling (5200 ha) and Cirata (6200) reservoirs, in terms of the number of net-cage units, total people involved and fish production, has been rapid (Annex 1), particularly in Cirata. The success has stimulated the villagers and investors at the downstream Jatiluhur (8200 ha), and at other reservoirs in central and eastern Java, Sumatra and Kalimantan to develop net-cage aquaculture. In the three Java reservoirs the success is evident from Table 1 and Annex 1.

Table 1. Status of net-cage aquaculture in Saguling, Cirata and Jatiluhur reservoirs in 1996 (West Java Fisheries Service, 1996).

LakeNumber of cage unitsNet-cage fish farmersFish yield tons

The fish produced are common carp (50%), Nile tilapia (40%) and several other species such as catfish (up to 10%). They are produced mainly for local and regional consumption. During the last two years, genetically improved Nile tilapia were produced for export to the US and other countries.


The development of net-cage aquaculture in Saguling and Cirata reservoirs faced a number of problems:

5.1 Implementation and control of regulation

Legal aspects of the net-cage aquaculture development in the Saguling and Cirata reservoirs, as well as for the other water bodies in West Java, are controlled by Provincial Regulation No. 11/1986 and its technical guidelines which have been effective since 1992. The regulation allows resettled families to operate four units of net cages, measuring 7×7×2 m each. Under Regulation and Memorandum No. 245/1992, one cage per hectare surface area at high water level is allowed, so there should be 4870 units in Saguling and 6200 units in Cirata (West Java Fisheries Service, 1996) and the distribution of the allowed number of netcage units should follow the proposed zonation made by PLN (the project) and Research Institute, Padjadjaran University. However, due to lack of control of regulation implementation, the numbers are exceeded, particularly in Cirata.

The excessive number of net-cage units is also associated with the inability of the responsible institutions to fully implement the regulation, i.e. to issue and control the possession of operational permits of widely distributed net-cage units in the reservoir as well as to control its management system and the identity of the owners. The excessive number of units may in turn reduce water quality and carrying capacity of the reservoir. Moreover, the unclear identity of the net-cage ownership may result in misleading information on the achievements of the aquaculture resettlement option.

Table 2. Ownership and type of net-cage units in Cirata reservoir (PLN Sector Cirata, 1996).

No.  Total
1Origin of net-cage owner:-local people1200
2Type of net-cage units:-bamboo frame23001
-metal frame2557
3Number of unit ownerships:  
 a. less than 4 units:-local people249
 b. 5–8 units:-local people407
 c. 9–21 units:-local people287
 d. more than 13 units:-local people258

A census made by PLN Sector Cirata in 1995 (Table 2) shows that of 2472 net-cage owners, only 1200 are local people, which is less than the number of outsiders (1272). It can be seen that of the local owners, the number of affected people possessing units is not clear, while the outsiders are not affected people and originate from Cianjur, Bandung, Jakarta, and other places.

Unfortunately, more local people possess fewer than 8 units, while more out siders have more that 8 units. This condition indicates that there should be a strictly enforced control and implementation of regulations.

5.2 Decrease of profit margins

Expansion of net-cage aquaculture markedly increases the demand for fish seed, feed and net-cage material and is followed by an increase in price of inputs, such as feed and seed, as well as service costs. Unfortunately, a significant increase in the input price is not followed by an increase in product price, so a decrease in profit margins can not be avoided.

Yield trials by the Research Institute, Padjadjaran University (1985) showed that one 7×7×2.5 m net cage in Saguling, stocked with 300 kg of 100-gram common carp fingerlings could produce 1.2 t in 3 months. This production would earn a net profit of US$ 425–600/unit/year, which could support a family of five above the current poverty level.

By 1996 the price of fish seed was almost three times and feed twice that of 1986. The cost of other inputs increased by 50 to 100 percent. Within the same period, the increase in fish price was less than 50 percent. As fish feed constitutes almost 60 percent of the net-cage operational cost, the relatively small increase in price significantly reduces the profit margin. According to Saguling fish farmers, the feasible number of net-cage units is now three, compared to one unit in 1986. This shows that the increase in costs has primarily affected the small-scale net-cage owners, who are mainly the local people.

5.3 Reservoir water quality

Success of net-cage aquaculture very much depends on the reservoir water quality. In Saguling and Cirata reservoirs the water quality fluctuates. The quality declines when pollution exceeds a critical level. Pollutants may originate from the upstream river and its tributaries or from the activities in the reservoir itself, i.e. excess feed and excreta. Most pollutants accumulate on the bottom, and under the impact of thermal destratification and/or wave and current action they may re-enter the water column. This may lead to fish kills.

A great number of fish kills were recorded in Saguling where 1000 t (12.86 percent of net-cage fish) were killed during 1993, and about the same amount in Cirata during 1994. This mainly occurred during the prolonged cool cloudy days and the early rainy season (November to January) in a reservoir area that was very crowded with net-cage units. These fish kills also indicate that controls and implementation of regulations are important. The information on fish kills in the three reservoirs over the period 1986–1996 is given in Annex 2.

5.4 Biotechnological aspects

The most popular fish species cultivated in net cages are common carp and, during the last three years, Nile tilapia. Demand for tilapia is high, but it fetches a relatively low selling price. This fish has a low food conversion ratio. This has contributed to the increase in reservoir water pollution due to the excess of feed used to grow this fish. The low price has led to a decrease in profit margins.

The Institute of Ecology (1996) noted that each net cage with fish in Saguling as well as in Cirata received 10.8 t/year of commercial feed. The feed contains 1 percent phosphorus, of which 0.55 percent is wasted ending in the water. From 4425 net-cage units in Saguling, a total 262.8 t of P is released to the water, while in Cirata with 25,558 units, a total of 1519.9 t of P is released. To utilise the excess feed, the local Fisheries Service developed a double and triple layer net for the cage. In the second and third layer of the net, fish tolerant to low oxygen, i.e. catfish and Nile tilapia were stocked. The fish can utilise the excess feed falling down from the upper layer.

As the selling price of the two fish species is still low and the potential for water pollution by organic wastes is relatively high, dependency on these two species for net-cage culture should be supplemented by a more economically valuable species. In the meantime, fish with a low food conversion ratio should be replaced by better species or brood fish should be improved to produce a better quality of fish seed. The solution consequently requires advanced technology in fish breeding and feed formulation, and the extension programme will accelerate the adoption of developed technology in order to overcome the problems.


The implementation of extension for net-cage aquaculture in Saguling and Cirata hydropower reservoirs was successfully achieved through a systematic and holistic approach under the co-operative work and close co-ordination with the target people, related institutions and local government. Sustained effort and strategies were applied in the implementation of the extension programme.

Related institutions involved in the extension programme are the West Java Hydropower Project (as a leading agency during the project establishment period), West Java Fisheries Service (leading agency afterwards) Research Institute for Inland Fisheries, Padjadjaran University, the local government and target people. Banks and co-operative agencies are also involved. Extension programmes are initiated by field studies, followed by field trials, group discussions, field training and other forms of learning.

Problems mostly appeared following the adoption of the extension advice. The large-scale development of net-cage aquaculture in Saguling and Cirata has been accompanied by the reduction in profit margins, degradation in water quality, weakness in the implementation and control of regulation, and limitations in technology and management ability.

To maintain a net profit the net-cage farmers have started to use genetically improved Nile tilapia, catfish, floating pelletised feed, as well as applying a double or triple layer of nets. Marketing and fish handling continues to be managed by the local fish farmers.


For the implementation of an extension programme in net-cage aquaculture, good co-ordination among related institutions and agencies, target people and the local government is most important. Sustained effort and good strategies assist with the implementation of the programme using systematic and holistic approaches.

The existing regulation needs to be implemented and strictly enforced to control the impacts and problems associated with the application and adoption of extension advice. Further extension programmes are needed to improve the ability of fish farmers to overcome the problems they face with the better management practices being implemented in net-cage aquaculture.

Annex 1. Status of net-cage aquaculture in Saguling, Cirata and Jatiluhur Reservoirs, 1987–1996.

- Cage units805123613511724180020754250442544254425
- Owners3334825155816016931193123612361236
- Yield(ton)1806255427853113365850668332755340683883
- Cage units-743518991613205638206473769022558
- Owners-2580210358469936149817164994
- Yield(ton)-32572997280348508195127081286242750
- Cage units-1514631250254665085012541254
- Owners---445390101115140140
- Yield(ton) 114235831197326792149119925472070

Note: In Cirata and Jatiluhur, net-cage production started in 1988, while in Saguling in 1985.

Annex 2. Fish kill in Saguling, Cirata and Jatiluhur Reservoirs (1986–1996).

YieldFish KillYieldFish KillYieldFish Kill

Note: No fish kills in Saguling during 1992, in Cirata until 1989, and in Jatiluhur until 1995.


Institute of Ecology, Padjadjaran University. 1996. Report on water quality monitoring of Saguling reservoir. PLN, Jakarta. 26p.

PLN Sector Cirata. 1996. Inventory survey on the ownership of net-cage units in Cirata. 15p.

PLN West Java Hydropower Project. 1990. Report on the development of fisheries in Saguling and Cirata reservoirs. Quarterly Report January–March 1990. 14p.

Research Institute, Padjadjaran University. 1985. Study and training net-cage aquaculture for affected people of Saguling reservoir. Bandung. 38p.

Sutandar Zainal, B.A., B.A. Costa-Pierce, Iskandar, Rusydi and H. Hadikusumah. 1989. Aquaculture resettlement option in the Saguling reservoir, Indonesia: its contribution to an environmentally oriented hydropower project. Paper presented at the Asian Fisheries Forum, Tokyo, 1989. 12p.

West Java Fisheries Service. 1988. Report on the development of aquaculture and fisheries programs in Saguling and Cirata reservoirs. Bandung. 8p.

West Java Fisheries Service. 1996. Development of net-cage aquaculture activities in Saguling, Cirata and Jatiluhur reservoirs. Bandung. 14p.

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