by
D.H. Yusuf, R.S. Pahlevi and P. Tambunan, Directorate General of Fisheries, Jakarta.
Cage culture of common carp in West Java.
1. SUMMARY
About 70% of Indonesian national fisheries production comes from the marine fisheries catch and only 30% is derived from aquaculture production and the open-water catch. Nationally, the exploitation of marine resources is still low but in certain areas, such as the Java Sea, Malacca Strait, and Bali Strait, the fishing grounds are crowded. Due to the high potential of Indonesian natural resources for aquaculture and over fishing of several fishing grounds, aquaculture development gives some positive hope in terms of reducing pressure on marine natural resources, creating new job opportunities and as a source of livelihood. Meanwhile, like many other countries, Indonesia is facing some environmental problems related to aquaculture development. These problems have been particularly manifest in the appearance of several kinds of shrimp diseases and degradation of water quality. This report examines how far the implementation of environmental assessment and management of shrimp culture and carp culture has progressed in Indonesia.
2. INTRODUCTION
Indonesia, the largest archipelagic state in the world, stretches west from the Indian Ocean to the Pacific Ocean (a distance of over 5,000 km) and straddles the equator for a distance of 2,500 km north to south. The Indonesian coastal zone spreads along 81,000 km, which is the second longest coastline in the world after Canada. The coastal area is endowed with rich and varied natural resources, including both living and non-living. Its vast natural resources have contributed directly to the current status of Indonesia as a major aquaculture producer and its natural aquaculture development potetial. Although aquaculture accounted for only 30% of the Indonesian national fish production, this activity plays an important role in fisheries development in Indonesia. The average annual increase in aquaculture production is higher than the increase in marine fishing activity. For example, from 1986–1991, fish production from marine fishing increased by 5.0% annually, whereas the annual growth in aquaculture production was 8.5%. The increasing role of aquaculture in fisheries production can be shown by the increase in its contribution to total fish production. In 1986, the contribution was around 13.2%, but by 1991 it had increased to 15.4%. On the basis of this, the contribution of aquaculture to the fisheries national product is expected to increase in order to meet the requirement for animal protein consumption and also as a source of foreign exchange from the non-oil sector. Indeed, Indonesia has good prospects for aquaculture development since it has vast potential resources from inland and coastal ecosystems, a good climate, man power, as well as other supporting elements.
Map of Indonesia.
This report presents baseline information on the current environmental situation relating to aquaculture activities in Indonesia, particularly the impact of aquaculture on the environment and the impact of the surrounding environment on aquaculture. It is expected that the results of the workshop will be used as a basis on which to design further detailed studies related to the environmental implications of Indonesian aquaculture development. It is also hoped that recommendations for further research, training and information exchange at national and regional level will be made. The report covers in detail shrimp and carp culture activities in several locations and research centres in Indonesia. It was carried out by collecting primary and secondary data from several provinces and research centres which are representative of the national situation with respect to shrimp and carp culture.
3. STATUS OF AQUACULTURE
Indonesian aquaculture is divided into three main groups, namely: freshwater culture; brackishwater culture and mariculture. Freshwater and brackishwater culture have long been practised by Indonesian fish farmers, while mariculture, despite the abundant resources, is a new development that has only been carried out since the early 1980s. Indonesian aquaculture is mostly small-scale and characterised by low technological inputs and a high degree of dependency on nature. In 1991, there were about 1,800,000 fish farmers engaged in aquaculture activities, including 175,000 people involved in brackishwater culture and 1,600,000 in freshwater culture. There are no data available on the number of fish farmers engaged in mariculture, but the number is still low.
Recently, aquaculture development in Indonesia has accelerated and it plays an important role in supporting rural economic development. Moreover, since the banning of trawlers in 1980–1981, the government has put a high priority on developing shrimp and prawn culture from brackishwater and freshwater ponds. The aim of this is to counterbalance the loss of shrimp production from marine trawl fishing and also to boost foreign exchange earnings from exports.
The Indonesian national strategy for developing aquaculture can be summarised as:
Increasing production levels of fish farmers through technological improvement;
Increasing natural aquaculture production through the intensification of existing areas under culture;
Increasing the income and opportunities of fish farmers as a result of (1) and (2) above;
Encouraging diversification in crop production, particularly for cultured species which have a high economic value;
Maintaining and increasing the supply of non commercial fish and other fish products for the benefit of low productivity land in particular.
3.1 Freshwater culture
Freshwater culture operations are usually practised by Indonesian fish farmers in static ponds, rice fields, fish cages/pens/floating nets and running water ponds, on the basis of the land characteristics and people's customs. The species cultured are: common carp (Cyprinus carpio), Java carp (Puntius javanicus), Java tilapia (Oreochromis mossambicus), Nile tilapia (Oreochromis niloticus), gourami (Osphronemus goramy), spotted gourami (Trichogaster pectoralis), kissing gourami (Helostoma temmincki), and carp (Osteochillus hasselti). The culture of giant freshwater prawn (Macrobrachium rosenbergii) has been developed in some places, particularly in the provinces of West, Central and East Java and Yogyakarta.
Fish cage culture is usually practised in rivers, irrigation canals, and open waters (lakes and reservoirs). It is practised on a small scale basis in the provinces of West Java, Jambi, South Sumatera and Province of Kalimantan. West Java is the most advanced province in fish cage culture activities and the annual fish production in net cages in West Java has increased sharply in recent years. In 1991, production increased by 77.8% compared to 1990, or from 5,025.5 tonnes in 1990 to 8,934.3 tonnes in 1991. The reasons for this sharp increase in production from net cage culture include:
Cage culture gives more benefit than other forms of freshwater fish culture due to lower production costs;
The number of fish culture households increased from 841 in 1990 to 846 in 1991, due to the good climate for this activity;
The culture area increased by about 96% from 1,976 units in 1990 to 3,682 units in 1991.
3.2 Brackishwater culture
Until 1975, the main species cultured in brackishwater ponds was milkfish (Chanos chanos), while the other species, including penaeid shrimp, were still considered by-products of brackishwater pond culture systems. Since 1975, penaeid shrimps particularly tiger shrimp (Penaeus monodon) and white shrimp (P. merguiensis), have also been cultured in brackishwater ponds either in monoculture or in polyculture systems with milkfish. Based on production levels, inputs and water management, three types of brackishwater culture technologies have been developed, namely: extensive; semi-intensive; and intensive.
In extensive systems, the species under culture subsist on natural food grown with fertilisation and the pond water is exchanged by tidal flushing. The number of seeds that are stocked is also limited to 2 fry/m2. Production is usually around 0.4 t/ha/crop. In semi-intensive systems, the culture technique involves a higher stocking rate of 6 fry/m2 and supplementary feed (2.3 t/ha/crop) is administered. To increase oxygen levels in the water supply to the pond, it is necessary to use water pumps occasionally. There are usually two crops per year and the expected production is around 1–2 t/ha/year (from two crops).
In intensive systems, shrimp culture is totally dependent on formulated feeds with a continuous supply of water. Pumps and paddle wheels are used to increase oxygen levels. Under this culture system, it is possible to get 2–3 crops per year with the total production around 5–8 t/ha/year or more. Intensive culture began in 1985–1986, much later than the other forms of shrimp culture, and has developed rapidly since then. The rapid development of intensive shrimp culture in Indonesia was possible for the following reasons:
The availability of hatchery and growout technology;
The operation of an adequate number of hatcheries for the supply of shrimp fry;
The availability of artificial feed and various equipment and inputs required for intensive culture;
A good marketing system.
3.3 Mariculture
Mariculture is a new development in Indonesia, despite the potential of its vast resources. Some fish farmers have been cultivating different commodities and species on a very small scale at several places in the country, such as finfish culture in pens and floating net cages in Tanjung Pinang (Riau Province), Belitung Island (South Sumatera), Serang (West Java) and West Nusa Tenggara. The cultured species are: groupers (Epinephelus tauvina), siganids (Siganus javus) and sea bass (Lates calcarifer). The culture of seaweed has also been conducted in several places, especially in Bali, west Nusa Tenggara and Lampung, involving Euchema sp. In South Sulawesi, the culture of Gracilaria is conducted by some farmers in brackishwater ponds, which are not productive for shrimp culture, as part of a polyculture system with milkfish.
A few years ago, the Government encouraged the culture of green mussel in some provinces, such as in Jakarta, Lampung and Kalimantan. In 1989, the total shellfish production was 55,434 tonnes, however, shellfish culture in Indonesia is largely experimental at present, except for pearl oyster culture. Pearl oysters of economic importance and with a high potential for seafarming development include Pinctada maxima, P. margaritifera, P. fucuta and Pteria penguin. There are at least 25 companies currently involved in pearl oyster culture in several areas in Indonesia. Some of the companies located in West Nusa Tenggara are Mitra Nusa in East Lombok, Dian Bahari Utama in Sumbawa, PT. Paloma Agung in Sumbawa, Bendera Mutiara Bahtera in Dompu, and Lombok Pearl Indonesia in Lombok.
4. INTERACTIONS BETWEEN AQUACULTURE AND THE ENVIRONMENT: GENERAL REVIEW
4.1 Impacts of environment on aquaculture
4.1.1 Inland aquaculture
There is some information on the impact of environmental change on inland aquaculture. The following is a summary of the information collected.
Physical impacts
No information was available on the impact of sedimentation and siltation on inland aquaculture.
Although water shortages and flooding occasionally hamper inland aquaculture activities in several
places, there was no exact information on losses suffered by inland aquaculture.
Industrial wastes
Although tanning wastes and mining effluent (among others) were reported as important pollutants in
some areas, no information was available on the impact of such industrial wastes on aquaculture.
Pesticides and fertilisers
Over the period between 1969 and 1986, the use of pesticides for food crops increased from 1,240 to
17,350 tonnes per annum. Fertiliser use also increased during this period, and 3.1 million tonnes of
fertiliser were applied in 1987, or approximately 199 kg/year for each hectare of agriculture land.
However, the National Committee of Pesticides regularly control and reduce the volume of pesticides
used in agricultural activities, including aquaculture.
In 1986, the government banned the use of 57 insecticides and promoted integrated fish culture. The government have also instituted a strict “screening” procedure for new pesticides which includes consideration for their potential toxicity to fish. The adoption of integrated pest management strategies and fish toxicity “screening” appears to have had some success in reducing the impacts of pesticides on fish. The culture of fish (mainly common carp, Cyprinus carpio) in rice fields is reported to have helped reduce the use of pesticides in irrigated rice fields (farmers being less willing to spray because of the valuable fish crop - and requiring to spray less because of reduced pest problems in rice fields containing fish).
Where spraying has taken place in rice fish culture, farmers may concentrate fish into deeper parts of the rice field where they do not spray. The success of the overall Government strategy can be gauged from the volume of pesticides used, which has declined sharply. In 1988, the total volume used by farmers was 12 million litres and in 1990 the volume was reduced to 7 million litres (Indonesia Report to UNCED, 1992).
Domestic waste water
Domestic waste water, containing nutrients and organic matter, provide both problems and opportunities
for fish culture. In certain aquaculture systems domestic wastes provide a source of nutrients and
organic material for aquaculture. For example, in the culture of common carp in bamboo cages in
irrigation canals in Cianjur, domestic wastes may contribute to the aquatic productivity of irrigation
canals, and indirectly, to the productivity of carp cages. Semi intensive pond culture may also benefit
from domestic wastes. Utilisation of such wastes in fish pond culture can put potentially polluting
wastes to productive use. In more intensive aquaculture operations, water with high loads of nutrients
or organic material may not be suitable for fish culture.
Petrochemical discharges
No evidence was available suggesting petrochemicals have had a negative impact on inland fish culture
in Indonesia.
Phytoplankton blooms
In freshwater reservoirs, blooms of cyanobacteria (Microcystis sp.) are reported to adversely affect
common carp cultured in cages. However there is still no further information regarding this case.
Spatial use conflicts
Up to now there is almost no conflict in using the area for inland aquaculture and for other purposes.
Other environmental impacts
There is no further information of other environmental impacts on inland aquaculture.
4.1.2 Coastal aquaculture
The environmental problems affecting coastal aquaculture differ considerably from place to place in Indonesia. In general, problems are more severe around the highly populated island of Java and, to a lesser extent, on parts of Sumatera. In less populated areas, there are also problems of contamination arising from coastal urbanisation and agricultural and industrial development. In a recent study of the marine environment in Sumatera, the following problem were noted:
Industrial waste;
Domestic waste from major population centres;
Hydrocarbons from oil spills and land based discharges;
Siltation and sedimentation;
Pesticides pollution from agricultural activities.
In general, the effect of such man made environmental changes on aquaculture have not been determined. However, some information is given below.
Physical impacts
There are several impacts on coastal aquaculture related to physical changes in the environment,
particularly siltation and sedimentation. For example, built up land always occurs along the northern
coast of the island of Java, which produces two main impacts. Firstly, water currents become slower
and this affects the discharge of shrimp ponds in the area. Secondly, this newly built-up land has led to
the development of a huge number of new shrimp ponds and the establishment of an irregular canal
system, raising new problems in water supply and drainage.
The flooding of coastal areas, linked to upstream deforestation or other man made environmental changes, may have a disastrous effect on coastal aquaculture. For example, floods in Semarang area of Java during 1992 had a severe effect on coastal shrimp and milkfish ponds.
Industrial wastes
Although negative impacts of the establishment of pulp paper industries in the upstream area in Jambi,
and North Lampung have not yet been proved, many scientists are very concerned about the
establishment of these factories. Concerns have arisen due to the discharge of these factories to tambak
pond areas located downstream.
Pesticides and fertilisers
Since the establishment of Pesticide Committee, Indonesia has been controlling the use of pesticides.
Most shrimp ponds share a water supply canal which is also used for rice farms. The committee realises
that many pesticides are extremely toxic to shrimp and is responsible for making sure that the water
used by the shrimp ponds contains low levels of pesticides.
Domestic waste matter
Although no information is available on this subject, this type of waste is a potential hazard to
aquaculture.
Petrochemical discharges and oils spills
There have been some severe oil spills in Indonesia marine waters. The largest oil spill occurred with
the grounding of the 237,698 dwt Showamaru on January 6, 1975. It spilled more than 7,000 tonnes of
crude oil into marine waters.
Phytoplankton blooms
Not much information is available on this subject, although red tides in Lampung and Jakarta Bay have
been reported.
Salinity fluctuations
The variation in the salinity of shrimp pond waters also has an affect on shrimp production. In general,
farmers report lower yields during the rainy season. Where shrimp farms use irrigation canals, salinity
variations caused by man made and natural changes in freshwater run off may also affect shrimp pond
yields.
4.2 Contamination of aquaculture products
There is little information on the contamination of aquaculture products. The following is a summary of the information obtained.
Microbial contamination of molluscs
This problem has been reported from Jakarta bay, however, no further information was available.
Heavy metal or pesticide contamination
In some areas, contamination of mollusc has occurred, e.g. with lead and cadmium in parts of Sumatera
and in Jakarta Bay.
Chemotherapeutant contamination
The use of antibiotics in shrimp ponds is reported to have led to some residues problems. There is one
reported incident where oxytetracycline residues were detected in a shipment of shrimp exported to
Japan, which resulted in the shipment being rejected.
Other contaminant problems
No other contaminant problems were reported.
4.3 Impacts of aquaculture on the environment
This section aims to give a description of the environmental problems caused by aquaculture. The review covers the major aquaculture systems in Indonesia.
4.3.1 Inland aquaculture
There is little information on the environmental impacts related to most forms of inland aquaculture development. Semi-intensive pond culture is regarded as “environmentally benign”. Problems have been reported for intensive cage culture of common carp in reservoirs. Semi-intensive and extensive culture of fish in rice fields is thought to have a positive impact on the environment by reducing use of potentially polluting pesticides. Some general details are given below.
Impacts on the physical habitat
In Cianjur, the culture of common carp in bamboo cages located in irrigation canals is reported to have
led some minor effects on water flow and flooding in canals (Dr S. Koesoemadinata, Research Institute
for Freshwater Fisheries, pers. comm, 1993). However, this type of culture is not widespread and so the
overall impact is considered minor.
Impacts on water quality
In most cases, there is no information on the effects of inland fish culture on water quality in inland
waters. In the mid-1980's raceway culture of common carp was reported to have had some impact on
the water quality (particularly the organic content) of irrigation canals (e.g. in Ciawi, West Java).
However, no quantitative data are available. Raceway culture is now less common in West Java and
production of common carp appears to have moved more towards cage culture in reservoirs (mainly
Cirata and Saguling). The detrimental effects of the raceway culture cannot be quantified. In some
cases, disease outbreaks in “downstream” common carp raceways were linked to pollution of irrigation
canals by release of effluent from “upstream” carp farms. However, no quantitative data exists, and it is
possible that problems were also linked to the pollution of canals by domestic and agriculture run-off.
As far as is known, there are no other reported effects of inland fish culture on water quality in inland waters in Indonesia. The exception is cage culture, which is discussed in more detail in Section 5.
Chemotherapeutants
No information on this subject was available.
Interactions between aquaculture and native fish species
There are instances where the introduction of fish species for aquaculture (and fisheries enhancement)
may have had an impact on native fish species. For example, the loss of indigenous fish, Oryzias
celebencis, in Lake Tempe (South Sulawesi) is reported to have been due to introduction of several
species of exotic fish for fisheries enhancement purposes.
It has been reported that culture of snakehead (Ophicephalus sp.) and marble goby (Oxyeleotris marmorada) in shallow lakes in Kalimantan may exert some influence on local fish species (Dr. A. Sarnita, Research Institute for Freshwater Fisheries, pers. comm., 1993). There are reportedly around 3,000 cages in Lakes Semayang, Melintang and Gempang. The culture of both species (which are predators) relies on wild fish which are cought from the lakes, but in among the fish used for feed there are some juveniles of commercially important fish (e.g. Leptobarbus sp.). The effect of this practice is difficult to assess from present information, however, given the rather low value of the species cultured -- the price of snakehead is reported as between 2,000 and 3,000 rupiah per kg -- the practice is unlikely to be widely adopted. It can only be sustained in those areas where fish are unusually abundant relative to demand.
Social conflicts and aquaculture
Farmers displaced when reservoir waters inundate agriculture lands have been given the opportunity to
become cage culturists and fishermen on the reservoir concerned, as an alternative source of income.
The development of cage culture of red tilapia for export has caused non-farming entrepreneurs to
invest in cage culture in some reservoirs. The local farmers turned cage culturists and fishermen have
two complaints. Firstly, they feel that they have been deprived of space, and secondly, when tilapia
unsuited for the export market are placed for sale in local fish markets, there is downward pressure on
the general price level for fish and their income is reduced.
Other environmental impacts
No further information was available.
4.3.2 Coastal aquaculture
The environmental impacts of coastal aquaculture are related mostly to the development of shrimp and milkfish culture in coastal ponds (“tambaks”). Several impacts have been identified for these culture systems, however in most cases, quantitative data are lacking. There are no reports of environmental impacts related to marine cage culture, seaweed or mollusc farming. This section gives a general overview of the impacts related to coastal pond culture.
Impacts on the physical habitats
Coastal pond culture in Java has a history of several hundred years. During the last few decades, there
has been extensive conversion of mangroves in Java to milkfish and more recently shrimp ponds. The
development of ponds and associated irrigation canals to supply and drain culture areas has had physical
impacts on the coastal environment in Java and other parts of Indonesia.
Impacts on coastal water quality
Apart from some studies on water quality in shrimp ponds and shrimp farming areas, there has been
little study of the effect of coastal aquaculture on water quality. It is generally thought that semi-intensive
shrimp farming may have a detrimental effect on water quality if there is a high density of
ponds in a given area, or if the water supply or water circulation in a farming area is limited. The results
of available studies are discussed further in Section 5.
Impacts of coastal aquaculture on mangroves
The development of coastal pond culture has had some impact on coastal mangroves forests. This
aspect is discussed in Section 5.
Chemotherapeutants
There are a number of chemotherapeutants used in coastal aquaculture in Indonesia. The impacts of
these chemicals on the environment is largely undetermined. Researchers in Jepara report that
continuous use of Brestan in extensive shrimp ponds in Aceh Province has left ponds sterile and
unproductive. However, in a recent study in North Sumatra, use of thiodan was reported to have had no
negative environmental impacts.
The effect of antibiotic use in hatcheries, and to a lesser extent in shrimp grow-out ponds, are important. This aspect is discussed in more detail in Section 5. There are several chemicals used in shrimp hatcheries and by pond farmers growing shrimp and milkfish.
Interactions between aquaculture and native fish species
Again, there are little data on this subject.
Social conflicts and aquaculture
There are reports of some conflicts between different resource users in the coastal zone. Examples
include the effects of cage culture and seaweed farming on navigation and tourist interests in some
coastal areas. The conversion of mangrove areas into tambaks by “outsiders” can be a source of conflict
between them and those local inhabitants who traditionally have been exploiting the mangroves.
Other environmental impacts
No information available.
5. INTERACTIONS BETWEEN AQUACULTURE AND THE ENVIRONMENT: IN-DEPTH STUDY
5.1 Coastal shrimp culture in Indonesia
5.1.1 Introduction
There are several environmental impacts related to shrimp farming in Indonesia. However, the analysis of impacts is constrained by a lack of quantitative data.
5.1.2 The environmental impacts of shrimp farming
Impacts of shrimp hatcheries
For hatcheries, there are several environmental issues to be considered. For example, in some areas,
there are localised concentrations of hatcheries (11 in Banyuwangi; 15 in Sukabumi; and 40 in
Situbondo). In Jepara, there are at least 400 “backyard” hatcheries. There is some advantage in
concentration, in terms of co-operation among farmers (e.g. sharing of water pumps among backyard
hatchery owners), however, this may be offset by collective exposure to localised environmental
problems, (such as luminescent bacteria and antibiotic resistant bacteria) from the effluent of adjacent
hatcheries. There is no indication that such concentrations are having any impact on other resource
users. However, such concentrations may have negative impacts on the shrimp hatcheries themselves,
e.g. through increased disease problems and difficulties in treating outbreaks of disease. Antibiotics
which are widely used in the hatcheries include: chloramphenicol, erythromycin, oxytetracycline,
prefuran and furazolidone. Treflan is used at 0.2–0.4 ppm as a prophylactic treatment against fungus in
some hatcheries.
The environmental impact of antibiotic use is largely unknown. Antibiotic use affects larval quality. It was reported by scientists in Jepara that pond farmers using antibiotic treated shrimp post-larvae performed less well in grow out ponds (poor survival, poor growth) in comparison with post-larvae reared in antibiotic free environments. Pond farmers are reported to be more aware now of the importance of larval quality and avoid post-larvae reared in antibiotics. It is sometimes difficult for pond farmers to check the use of antibiotics in hatcheries (although not impossible, as some pond farmers do visit the hatcheries to inspect and make advance orders for post-larvae), and there appear to be some market forces being brought bear on hatcheries to control the use of antibiotics. Such pressures may help reduce any environmental problems linked to the use of antibiotics in hatcheries.
Water quality regulations
At present, there are no regulations requiring treatment of hatchery effluent. In Jepara, it is reported that
hatchery owners will be requested by the local government to install drainage channels for discharge of
effluent. Although there are no specific regulations concerning the treatement of hatchery effluent, we
have some rules with regard to the control of water quality.
1. Government Rule Number 20, 1990, concerning The Control of Water Pollution.
This rule, established as the implementation of Law Number 4, 1982, article 15, stated that “environmental protection [should be] conducted based on environmental standards” (Law Number 4, 1992 is the basic law of Environmental Protection and Management). This Government Rule (in Indonesia called as “Peraturan Pemerintah” number 20/1990, or PP 20/1990) stated that criteria and pollution standards should be based on water quality standards depending on the allocation of water use in the water source concerned.
In the terminology of water pollution, water allocation is linked to water quality standards (a basic standard for comparing the level of pollution in waters) and hence is the basic parameter for controlling the water pollution. In article 7, PP no 20/1990, water-use allocation is classified into 4 categories:
Group A: Water which may be directly used as drinking water without having to be processed in advance.
Group B: Water which may be used for raw water for drinking water.
Group C: Water which is intended for fisheries and animal husbandry activities.
Group D: Water which may be used agriculture needs, and could be utilised for city businesses, industry, water energy and electric plant.
The establishment of these allocations, depends on the condition and characteristics of the water, which is decided by the Governor of the Province concerned or by the State Minister for the Environment. This is with the exception of water sources under the jurisdiction of management authority as stated in Law number 11, 1974 about Irrigation (this is now under Minister of Public Work, in the past there was the Minister of Irrigation).
2. Decree of the State Minister of Environment number 03/1991, regarding the Allowable Standard of Effluent of the Industries Activities (there are 14 kinds of industrial effluent regulated in this decree). There is also a specific rule for the effluent discharged into the sea (article 27, PP no. 20/1990).
Impacts of shrimp pond culture on mangroves
The development of milkfish and shrimp farming in Indonesia has led to the loss of coastal mangroves.
Mangroves provide coastal protection from erosion and typhoons areas. Provision for coastal protection
in Indonesia has been provided by Presidential Decree No. 32/1990 which allows for a green belt of
mangrove area which is a minimum of 130 times the difference between highest and lowest tide levels.
Impacts of shrimp pond culture on water quality
One effect of the discharge of shrimp pond effluent is that of water quality deterioration in water supply
canals. This problem will be worse in the following circumstances:
There is a high density of ponds discharging into the same canal;
The canal is used both for water supply and discharge;
Flushing of canals is poor, water exchange is limited, sedimentation is high and engineering and/or design is poor.
In such circumstances, farmers commonly report disease outbreaks and reduced pond yields. There are several ways in which farms and government have responded to the environmental problems which have arisen with shrimp pond culture. In most cases, satisfactory solutions to the problems have yet to be found. The development of effective methods to manage the shrimp farming environment is regarded as crucial to the future sustainability of the industry. One technique which shows some promise is the co-operation among farmers in water management. An example is to be found in the Bulak Baru Village near Jepara where there are around 36 ha of shrimp ponds. The first of these ponds started operation in 1987. Ponds are still undergoing construction or upgrading from extensive to more intensive farms. Since 1992, farmers have suffered from reduced production in ponds and occasional complete crop failures. This stimulated the farmers to co-operate in paying for the deepening of the main water supply canal.
After repair, the problems were reported to be less severe. Farmers were charged Rp1 150,000 per ha for the cleaning (total of Rp 5.4 million). In 1987, after cleaning, profits are reported to have increased from an average Rp 2-5 million/ha/crop to Rp 12-14 million/ha/crop (or from 180 million/crop to 576 million/crop over the entire 36 ha of ponds). If these figures are correct, then the investment in canal renovation appears highly successful. Apparently, attempts to encourage farmers to co-operate in taking in and discharging pond water at the same time have not been successful. This may not be so critical in this village as pond effluent is released into a discharge canal which is separate from the water supply.
1 1 US $ = 2,200 Rp (approximately).
Apart from such “self-help” schemes, the Government is also taking action to reduce the environmental problems. The decree of the Minister of Agriculture number 237/1991, requires environmental impact study for certain agriculture activities. However, due to a Government Regulation No. 51/1993, a new ministerial decree regarding environmental impacts is in the process of formulation. The dredging of irrigation canals to improve water supply and drainage to farming areas is another example of action which is taken by the Indonesian Government to reduce environmental problems.
Research is also being carried out into alternative systems for treating effluents from shrimp farms (see Appendix I).
The Nucleus Estate System
The Government of Indonesia is implementing a transmigration programme in fisheries. This is used as
a means to shift the rural and/or fishermen population from densely populated areas to those islands
where the population density is still low. The programme involves both fisheries and aquaculture
schemes. In aquaculture there are schemes focusing on tambak developments and on the culture of
freshwater fish. In brackishwater fish culture the transmigration schemes take the form of “nucleus
estates”. The nucleus estates have two main partners: a private company on the one hand and a group of
shrimp pond owners/operators on the other.
The private company provides all inputs to the farmers, and buys the shrimp product from them. They also handle all post harvest activities. The farmers (plasms) generally own about one hectare of ponds, split up into two half hectare ponds. In addition, they are allotted a house and 0.25 ha for a backyard. At present there is one nucleus estate in operation at Jawai in West Kalimantan. The estate has a total of 460 ha of ponds. Of these 10–20 % are owned and operated by the nucleus private company; the remaining 80%–90 % are owned and operated by individual households. Table 1 shows the status of 8 schemes now being developed:
Table 1. Development status of nucleus estates in Indonesia.
| Location | Area of Pond (ha) | Remarks |
|---|---|---|
| 1. Jambi. | 262 | 1. Trial ponds in operation; Construction of canals; design completed (92). |
| 2. Central Kalimantan. | 200 | 2. Primary canals and trial ponds are being constructed. |
| 3. Kendari, Labo keo. | 300 | 3. Design completed (92); trial ponds are operated. |
| 4. Kendari, Muna. | 400 | 4. Design completed (92). |
| 5. Gorontalo. | 400 | 5. Trial ponds in operation; preparation of design work. |
| 6. East Kalimantan. | 400 | 6. Identification completed; Trial ponds are being constructed. |
| 7. West Nusa Tenggara. | 350 | 7. Ongoing. |
| 8. Riau. | - | 8. Identification completed; Trial pond is being constructed. |
Procedure for implementing a nucleus estate (see Table 2)
Table 2. Matrix of activities and agencies involved in setting up a nucleus estate.
| Operation | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 |
|---|---|---|---|---|---|---|---|---|
| Identification | + | + | + | |||||
| Land allocation | + | |||||||
| Nucleus company | ||||||||
information | + | |||||||
preparation | + | |||||||
feasibility study | + | |||||||
recommendation | + | + | + | |||||
permit | + | + | ||||||
| Trial ponds | + | + | ||||||
| Design (canals and ponds) | + | |||||||
| Land use loan | + | |||||||
| Construction | ||||||||
canals | + | + | ||||||
ponds | + | |||||||
housing etc | + | |||||||
| Selection of farmers and training Operation | + | + | + | + | ||||
first crop | + | + | ||||||
second crop onwards | + | + | + | + |
Code used above: 1. Local Government.
2. Ministry of Transmigration.
3. Ministry of Agriculture (DGF).
4. Ministry of Public Works.
5. Ministry of Co-operatives.
6. National Land Office.
7. Bank.
8. Nucleus Company.
5.2 Cage culture in reservoirs
5.2.1 Introduction
Culture of common carp (Cyprinus carpio) in cages in reservoirs in West Java has become increasingly popular in the past five years. In fact, the bulk of common carp production for West Java comes from reservoirs and cage farming and has overtaken the more traditional pond or raceway systems for culturing carp. In the past two to three years, culturing of tilapia in cages has also become popular. There are several environmental issues related to the culture of carp and tilapia in cages. Although, specific detailed studies are lacking, the following gives a general outline of the problems.
5.2.2 The environment and cage farming in reservoirs
The following issues have been identified:
Economic loss from “upwelling” of deep water
Such water is low in dissolved oxygen and high in toxic substaces such as ammonia and hydrogen
sulphide. The effects can be severe. In Cirata reservoir in west Java, 300 tonnes of common carp were
lost in 1989. Although fish can be sold dead, their market value is only about half that of live fish. The
estimated economic loss from this event is Rp 375 million (assuming an estimated market value of Rp
1,250 (50% of the price of live fish). The Research Institute for Freshwater Fisheries (RIFF) estimate
that 20% of fish cages are affected by fish kills each year.
The cause of this pollution event (which is reported from all the major reservoirs in west Java) appears to be cooling of surface water during the rainy season (usually September/October). The problem arises from three sources:
Nutrient and organic loading from reservoir catchment areas;
Nutrient and organic loading due to the wastes from the intensive cage culture;
Upwelling, due to lower surface temperatures, stratification and mix up.
The relative importance of these three sources is difficult to determine. However, in some limited areas, the loading from the cages is probably important. Monitoring studies carried out by the Research Institute for Freshwater Fisheries showed elevated concentrations of nutrients and reduced concentrations of oxygen in the area of the cages. Other issues, for which there is even less information are:
Impacts on capture fisheries (which may be positive as it is reported that wild fish are attracted to the cage area because of food availability). The escape of caged fish may also contribute to the capture fishery;
Exclusion of fishermen from fishing areas because of expansion of cage area;
The introduction of tilapia cage culture is reported to be resulting in the exclusion of small-scale common carp cage farmers from suitable farming areas. However, no further information was available on this subject.
The environmental problems that have arisen stem from a lack of effective planning of aquaculture development in the reservoirs (and lack of enforcement of existing regulations). It has become clear that regulations could not be applied as had been expected, mainly as a result of difficulties in law enforcement.
In 1991, there was a Minister of Agriculture Decree number 237/kpts/RC.410/4/1991 on the subject of “Criteria Improvement of Activities Under Responsibilities of the Agricultural Sector”. The decree covered conduct of a Preliminary study on Environmental Impact Assessment (PIL) and Preliminary Evaluation on Environment Impact Assessment (PEL). This decree, issued several years ago, was intended to be used by all proponents (which could be a private sector or a government Project/business), and the government has also has issued some technical guidance for basic direction in carrying out the EIA Study.
In freshwater aquaculture, the decree mentioned above stated that the PIL or PEL study should be conducted for each activity having a fish cage farm with at least 50 units, with the size of 50m2 each, or using the area of 5,000 m2 (at least). Other activities which were also obliged to do PIL or PEL study, were pen systems with a size of 300 m2 and totalling 10 units or more, or using the area greater than 5,000 m2 (at least).
Recently, (on October 23, 1993) the Government of Indonesia issued “Deregulation” in order to encourage investment in Indonesia. This includes deregulation on EIA criteria and procedure (the Regulation of EIA regulated in the Gov. Rules no 51/1993). Briefly, most activities in the agricultural sector, that were obliged to conduct EIA study from now on will now not have to. However, they maybe obliged to conduct Environmental Management Effort and Environmental Monitoring Effort (this is not an EIA study, but still needs technical guidance in the sector concerned). Besides, the existing regulations like Law no. 11/1974 and Government Rules No.20/1990 give the provincial government the authority to manage open waters, rivers, lakes and such things, including control and monitoring.
At the farm level, existing farmers manage their problems by selling fish immediately following a fish kill. There have also been some attempts to provide aeration, but these have not been successful. Ideally, the problems could be avoided by better site selection and farming fish within the “capacity” of the reservoir. It is known, for example, that certain areas are more susceptible than others to upwelling problems. Thus, some site survey could identify areas where cage farming could be less affected by such problems. Ultimately, each reservoir will have an upper limit for fish production, which needs to be determined.
The development of cage aquaculture in reservoirs also needs to be better balanced with other users (e.g. Capture fishermen). There are plans to “zone” reservoirs for different users, which would include zones for:
Capture fisheries;
Cage farming;
Navigation;
Conservation - no fishing areas;
Tourism; and
“No go” areas important for power generation.
However, such a scheme has yet to be implemented.
Appendix I
The use of green mussel (Perna viridis) as an alternative biofilter in an intensive shrimp farm.
by
S. Noor-Hamid and Pudjiatno,
Brackishwater Aquaculture Development Centre Jepara, Indonesia.
INTRODUCTION
The shrimp culture industry is considered the most profitable business within the agricultural sector in Indonesia. It began developing in 1985 and initially, environmental factors were within a manageable range. With the rapid development of the shrimp culture industry, however, more ponds were built and more intensive methods of shrimp culture were introduced. Most farmers were only interested in increasing stocking levels to maximise shrimp harvest. At this level of culture, disease outbreaks were reported from various shrimp producing areas and the country's annual shrimp production of 110,000 tonnes in 1990 was reduced to 85,000 tonnes in 1991 and 80,000 tonnes in 1992 (INFOFISH, 1993).
The first reported outbreak of shrimp disease was in the intensive farms in North Sumatera in 1988. A survey conducted in 1992 found that the failures of shrimp culture in Java was due to environmental factors. This was also identified as a cause of shrimp farm failure in East Java in 1993, where farmers reported the occurrence of one-month disease. Recently, diseased shrimp could be found throughout pond areas in Indonesia. In most cases, farmers tried to subdue the problems by applying chemical and enzyme products. Some positive action has been taken by fisheries institutions and universities in Indonesia, but so far the study of environmental factor has only been partially conducted, covering industrial pollution aspects (Anon, 1992), water quality aspects (Anon, 1992) and bacteriological aspects (Hambali 1992).
Water quality in shrimp culture systems is a key factor and production has a direct relationship with the level of water management required. The water for shrimp culture is taken from coastal waters, which was utilised for many activities, such as: tourism; industry; human settlement, fisheries and brackishwater aquaculture. These activities share in the destruction of the coastal environment as a result of their wastes.
Sedimentation and eutrophication are readily seen in coastal waters and the effect of coastal sedimentation is often obvious. During historical time, sedimentation in North coast of Java originated from large quantities of sediment due to frequent volcanic activity and intense rainfall. Recently, however, changes to watersheds by humans, are primarily affecting coastal sedimentation especially in Java where the intensity of land use is amongst the highest in the world. Shrimp culture activity is now contributing more to coastal sedimentation as this activity introduces enormous quantities of organic material into the water. For each tonne of shrimp harvested, at least 0.8 tonnes of organic waste are discharged to coastal waters. These wastes subsequently degrade and decompose.
INTENSIVE SHRIMP CULTURE IN INDONESIA
Methods of culture.
Indonesia has one of the largest coastal areas in the world and has enormous potential for fish and shrimp culture. In 1990 more than 30,000 ha had been developed into “tambaks”, a name used for the brackishwater pond in Indonesia. Aquaculture production and exports leapt to very high level. In the period 1983–1988, “tambak” shrimp production increased by as much as 24.5% per year, i.e. from 27,600 to 82,573 tonnes (Anon, 1989). The shrimp predominantly cultured is Penaeus monodon, produced using three culture methods: extensive; semi intensive; and intensive (Table 1).
The intensive shrimp farms are owned by big companies with big capital investment and usually they are not local farmers.
Table 1. The estimated percentage of intensive shrimp culture area in Indonesia (1991).
| Method of culture | Indonesia | Java |
|---|---|---|
| Extensive | 54% | 35% |
| Semi intensive | 40% | 55% |
| Intensive | 6% | 10% |
| Shrimp pond area | 96,811 ha | 55,433 ha |
Compared to other places in Indonesia, Java has good infrastructure facilities: electricity, roads, labour and communication. These facilities promoted the rapid and uncontrolled development of shrimp culture. The number of intensive ponds and pond holders are increasing every year as seen in Table 2. In recent years the new holders were traditional farmers who improved their ponds to semi intensive farms.
Table 2. The estimated percentage of pond developed for intensive shrimp culture in Java, 1989–1993.
| Method of culture | 1989 | 1990 | 1991 | 1992 | 1993 |
|---|---|---|---|---|---|
| Extensive | 95 | 90 | 55 | 49 | 39 |
| Semi intensive | 5 | 8 | 35 | 39 | 48 |
| Intensive | 0 | 2 | 10 | 12 | 13 |
| Total area % | 100 | 100 | 100 | 100 | 100 |
| Ha | 29,576 | 35,938 | 55,433 | 67,519 | 68,836 |
| Holder (unit) | 11,554 | 11,612 | 13,152 | 115,662 | 16,545 |
In some places the ponds were developed without technical consideration. For example, at Muncar Bay, Banyuwangi, East Java where the water system is totally dependant on the bay, hundreds of hectares of ponds were constructed within the period of 1988–1989. In the first year of operation most of the ponds were successful with good harvests, but the production was not sustainable. A continuous decrease in production was reported, beginning in 1991. According to an environmental study by the BADC Jepara, the problems were caused by environmental degradation. Since it is technically a closed water system, the bay is not able to provide adequate water supply for the culture area.
The most common shrimp culture techniques practised today is using a 0.3 ha to 2 ha pond, equipped with a water supply system and aeration. Good water management and proper feeding are always maintained to obtain a good harvest. With shrimp stocking densities of 30–35 fry per m2, the average harvest is 2–4 tonnes per ha per crop. With good feed conversion ratio (FCR) of 2:1 at least 4–8 tons of feed input would be required (Noor-Hamid 1992). On a dry weight basis, only about 20 % of the feed is incorporated into shrimp biomass, while approximately 6–8 tons of feed end up as waste. This waste is discharged to the coastal waters and decomposed to other material which may be toxic to aquatic animals.
Intensive farms are usually located near the coast to ease fresh sea water supply. In some parts of Indonesia the farms are built in 200–300 ha blocks with water supply and outlet systems. The farms have an average size of 0.5 ha are owned by small farmers and organised by farmer co-operatives, which are supported by a big company. This system is known as the nucleus pond estate (“Tambak Inti Rakyat, TIR”). Most of the ponds are operated with semi intensive culture methods and the average stocking density is 20–30 shrimp per m2. The nucleus pond estate system has 2 objectives: (1) rural development and (2) introduction of modern aquaculture technology to the farmers. With proper management, the farmers can harvest successfully. Successful harvests has been reported from TIR Lampung (over 250 ha of ponds) and TIR Kalimantan Barat (over 150 ha of ponds).
Sedimentation in shrimp culture.
Sediment production is actually a natural process but has increased as a result of human development such as building, housing, road construction, deforestation and also modern fish farming, all of which tend to increase erosion rates. Ecologically, accelerated sedimentation has caused environmental destruction. In shrimp culture, sedimentation can be observed by the accumulation of mud in the drainage canal. Currently, the wastewater from ponds is discharged almost daily into the outlet canal where there is potential for sedimentation. The discharged water also carries out the bulk of particulate nutrients in the form of heterotrophic and autotrophic macroplankton.
Ray and Chien (1992), concluded that stocking density was the main factor affecting the growth of shrimp fry while the age of sediment had a relatively slight effect. In their experiment the sediment has been sun dried for two weeks prior to use. This treatment partly mineralised the sediment organic content to around 5 to 6 ppm organic carbon, while the organic content of the water was still low, (1.8 to 2.2 ppm). In Indonesia today, the bottom soil of the pond is piled up on the dike and sun dried during pond preparation. Measurement of the organic content of the mud showed that it's organic level decreased from 6 to 4 ppm. After the water is drained out of the pond at harvest, the last part is mostly black mud which is pushed down into the canal to clean the pond. Ultimately, sedimentation of this matter shallows the canal and some of the matter is re-suspended with tidal currents and swept into coastal waters. In the BADC station where 20 ha out of 50 ha experimental ponds were used for intensive shrimp culture, the sedimentation rate reach 3 cm in one year at the mouth of the water inlet.
THE USE OF BIO FILTERS
As intensive shrimp farming requires inputs of high protein and phosphorus diets and a high rate of water exchange, a large proportion of the nutrients in shrimp feed become wastes which are discharged directly into coastal waters causing eutrophication. Increasing nutrient concentrations in coastal waters may also stimulate biological production, including growth of seaweeds and phytoplankton which will serve as food for shellfish and mollusc.
The mussel is a filter feeding animal which extracts suspended materials and detritus particles from the water column. Any suspended material, either organic or inorganic, may be filtered by the animal and some of it will be accumulated in the body. An adult oyster can pump up to 10 litres of sea water per hour through its body cavity, depending on its size, temperature and other biological and environmental factors. In Indonesia a species like Perna viridis settles in abundance in coastal waters and is a potential candidate for application as a biological filter. The filtering and absorption capacity of the mussel, Perna viridis was studied in BADC laboratory.
Methods.
The mussel, Perna viridis were collected from the waters around Jepara in August 1993 and held in a fibre glass tank for 2 weeks prior to use. Algae were given as food during this period. Twenty litre aquaria were used for the experiment and 10 individuals of 17–20 g were placed in each tank. The algae Skeletonema costatum were grown up to 300,000 cell per ml separately in an algal room. The algae were introduced to the aquaria at the beginning of experiment at varying concentrations. The aquaria were illuminated continuously with a fluorescent lamp to keep the algae alive.
Result.
It was found that during 18 hours of observation, the Skeletonema costatum cell concentration decreased. At a density of 104 cell per ml almost all of suspended algae has been filtered within 6 hours. While at 105 cell per ml it needed more than 15 hours to reduce the concentration below 101 cell per ml. Within the first 6 hours of the experiment, more than 50% of algal population has been absorbed in all level of algal concentration (Figure 1).
The absorption rate of the animal was affected by the concentration of the algae. Effective absorption occurred at higher algal concentrations. At 105 cell per ml, the mussel was able to absorb more than 13,000 cell per hour within 6 hours (Figure 2). The absorption rate decreased drastically after 6 hours but increased a little after 12 hours. Riisgard (1991) stated that at algal concentration of 1.5 × 104 cell per ml and higher, the filtration rate gradually decreases after an initial period of maximal filtration rate. The absorption rate was significantly higher at all levels of algal concentration in the first 6 hours and gradually decreased towards the end of experiment. The highest rate was in 105 followed by 5×104 and 104 cell per ml. Although individual biological observation was not conducted, this finding shows the animal satiation. Lower absorption rates were seen in the lower level of algal concentration. Animal satiation would took longer making the absorption rate more stable, as seen in the curve (Figure 1). At 104 cell per ml concentration, the algae was almost be totally filtered within 9 hours while in higher algal concentrations, it needed more than 18 hours.
The use of mussel as biofilters requires further study. Problems were observed when the mussels were absorbing water with high suspended material as this material may be concentrated in the gill column and will be pushed back into the water periodically. This material again will decompose in the water column. Apart from those materials, the mussel itself produced faeces that could be adverse to the shrimp and make the filtering system ineffective.
CONCLUSION
High organic loads in intensive shrimp farming result in high levels of suspended organic waste in its effluent. These wastes cause such impacts on coastal water quality as sedimentation, eutrophication and other environmental problems which threaten the industry itself. Water treatment of farm effluents is needed before coastal water quality worsens. The mussel effectively filtered the algae at all concentrations. The absorption rate is high in the initial period and gradually decreases as animal satiation is reached. In lower concentrations, the absorption rate is quite stable until the algae in the tank is totally filtered. Stable absorption rates occurred both in the 5×104 cell per ml treatment after 6 hours and the 104 cell per ml throughout the experiment.
REFERENCES
Anon, 1989. Indonesian Fishery statistic. Directorate General of Fish. Jakarta.
Anon, 1992. Result of survey on pond water quality in Gresik, East Java, Indonesia. Brawijaya University. In Indonesian 8 p.
Hambali, 1992. The result of microbiological analysis of shrimp samples from Gresik, East Java. Marine Fisheries Res. Centre. Gondol Bali, Indonesia. In Indonesian. 13 p.
Noor-Hamid 1992. Environmentally oriented intensive shrimp culture in Brackish water Aquaculture Development Centre, Jepara Indonesia. Symposium on coastal management. SEAMEO BIOTROP Bogor, Indonesia: 69–78
Ray, W.M. and Y.H. Chien. 1992. Effect of stocking density and aged sediment on tiger prawn Penaeus monodon, nursery system. Aquaculture, 104: 231248.
Riisgard, H.U. 1991. Filtration rate and growth in the blue mussel, Mytilus edulis Linneaus 1758: dependence on algal concentration. Journal of Shellfish Research, 10(1): 29–35.
Figure 1. The algal concentration taken every 3 hours during experiment
Figure 2. The absorption rate of the mussel during experiment
