REVIEW OF COASTAL WATER RESOURCES IN RELATION TO COASTAL AQUACULTURE

R. Djajadiredja and A. Purnomo, Inland Fisheries Research Institute, Bogor, .

ABSTRACT

The paper points out the potentials of the aquatic resources which may be utilised for culture purposes in the coastal waters of Indonesia. The habitats and distributions of the fry of some commercially important species such as milkfish, mullets, eel, shrimps and prawns in those waters are described. 1. INTRODUCTION

The important role played by coastal waters in the aquacultural development of Indonesia is as a source of supply of seed for cultural purpose. The culture of marine animals and plants in Indonesian coastal waters has not yet been extensively developed. Though in recent years some bivalve molluscs, such as Anadara nranosa (Ismail, 1970) and Ostrea spp. have been cultivated, other aquatic cultures in closed bays, in fenced areas or in live nets are not common in this country.

There is no doubt that in a country like Indonesia with its extensive coastline, capture fisheries may still offer great possibilities for increased fish production. However, coastal aquaculture may become more and more important in the future.

Coastal aquacultural development may remain a future prospect of which the realisation may depend on various factors,especially those of economic characters. Nevertheless, in view of certain aspects of coastal aquaculture there are signs of increasing interest in intensifying the cultural practice and in looking for possibilities of producing high price fish by this practice. Penaeid shrimps, giant fresh water shrimps, oysters and eels are among the highly appreciated products.

Coaetal waters are an essential source of seeds of various cultivable species. The vast acreage of brackish water ponds, which covered over 167,000 ha in 1970, depends solely on the seed stocks of milkfish, shrimps, mullets, etc. The annual requirement of milkfish fry, based on traditional stocking rate of 4,000 fry per ha per annum, is estimated as 439 million. The production of fry was estimated at 372 million in 1970. This indicates that there still exists a gap between the need and the demand. Although the production potentials are observed to be high in unexploited grounds such as the , Central and North Sulawesi, the islands of Ambon, etc., to reap such resources would require increases in effort and exploratory surveys. The existing grounds for seed collections should be protected from hazard caused by environmental pollution or other negative influences.

Considering the cultural practices of Penaeid shrimps, in which the existing method of stocking is based on natural supply of shrimp larvae entering the ponds, the total annual shrimp production varies from 8,500-12,500 tons. Taking these figures into account one may appreciate the hlgh potential of natural seed of shrimp in these coastal waters.

Wouraged by the high prices of shrimps, efforts have been made to produce shrimps under controlled conditions. In certain parts of the country people are trained to catch, transport, and store shrimp larvae. Intensive culture of shrimps has also been carried out with the improvement of ponds, water supply systems, and culture methods.

Coastal waters of Indonesia are also rich in resources of other economically important species which have not yet been utilised. In coastal waters adjacent to deep oceans, eels are abundant. Local people do not appreciate this kind of fish for food due to their beliefs, so that it remains unused for human benefit. Recent catching trials revealed that elvers could be caught easily in large numbers in waters along the southern coast of Java. Also, culture experiments prove to be promising. Probably hundreds,oftons of elvers and many more tons of yellow and silver eels could be harvested annually.

Oyster, a highly appreciated product in many countries, could only find a market in the foreign community in this country. Schuster (1949) described the possibility of oyster culture in Indonesia. We have initiated trials of oyster culture in central Java since 1954. Unfortunately due to marketing problems, farming of oysters cannot be expanded into a large-scale enterprise.

There is a type of culture.of Anadara granosa (Ismail 1970) in the coastal area west of Djakarta. This kind of product is served in restaurants as a special type of food. In developing coastal water resources the importance of i&&L, mangrove crabs and should not be overlooked. ,The first, although low in price, could in certain localities and circumstances be developed due to its abundance. In central Java people are familiar with seed collection and culture of species. Ir. time of scarcity instead of Chanos fry, the fry of this species may be used for stocking. ike to their high prices Scilla serrata, Lstes ~alcarifer,and Macrobrachium rosenberuii (altkough this iast-mentioned one is not a true inhabitant of coastal waters) should be taken into consideration for future development.

2. AREA AND SCOPE

The area utilised for coastal aquaculture is enormous and those having possibilities for future developmentaree-ren greater. The area for coastal aquaculture is distributed all over the islands as shown in Table I.

TABLE I Total area available for coastal aquaculture (1971)

Area of brackish water ponds in ha Developed Potential Total

Atjeh 16,254 75,4c0 91,654 Djakarta Municipal 1 ,530 - 1,530 West Java 28,543 10,000 38,548 Central Java 25,496 1,600 27,096 52,362 2,000 54,362 South Suiawesi 38,761 132,000 170,761 Other areas 5,953 (x) 5,953 (x) no data available

TOTAL

Apart from brackish water pond culture, cockle and oyster are also cultured in the shallow waters of the coastal zone area, though at present this type of culture is still in its infancy stage.

3. SPECIES CULTURED

For brackish water ponds, milkfish is the principal cultivated species. Shrimp, mullet, and tilapia come next and are considered as secondary products of the brackish water pond culture. Oqly recently, due to their good market prices, have shrimp and prawn been considered more important than milkfish. In some districts rearing of prawn depends not only on the natural seed which get into the pond with the in-going tide, but is also carried out by stocking the fry intentionally.

Table I1 indicates the brackish water species which are being cultivated or have possibilities for culture in Indonesia.

TABLE I1 Cultured and Cultivable Species

3xtent of development in Brackish water pond Freshwater pon& Coastal water FINFISH 1. Chanos chanos (Forskil) Extensive Extensive 2. && spp Small scale - 3. calcarifer Still no expt. - 4. Tila~iamoaaambica E;tenuive Extensive 5. Anmilla spp. - Experimental CRUSTACEANS Prawns and Shrim~s I. Penaeus monodon Moderate with or without milkfish 2. P. indicus lonnirostris Extensive traditional method 3. P. merauiensis 4. Metapemeus monoceros 5. g. brevicornis 6. g. burkenroadi 7. Macrobrachium rosenber~ii

I. Scylla serrata Still no experiment

MOUUSCS Oyster -Ostrea spp. Small scale Clams and Mussel I. Anadara manosa Small scale 2. Mvtilus spp. Catching

4. HABITATS AND DISTRIBUTIONS

The seed of those cultured and cultivable species as listed in Table 11 are obtained from natural habitats. In 1970, artificial propagation of some species of penaeid prawns has been successfully conducted and a mass production of seeds has been started this year. Under this paragraph only those species already advanced in their cultural management are discussed.

4.1 Finfish

4.1.1 Milkfish (Wnos chanos) fry

Environment

Gently sloping coastal waters, in most cases with small rivulets. Bottom is mostly sandy, occasionally with patches of stones or dead and living shells. In some cases the bottom is stony. The coastal plain is subjected to tidal fluctuations, exposed during low tide and flooded up to 2 m deep during high tide. The water is moszly clear with high salinity.

Distribution

Sumatra : North coast of Atjeh from Kutaradja to the mouth of Djamboaje River (300 km) Samalanga, Wra IXla, Lho Sukon, Iho Seumawe. South Pagai Islands off the west coast of Sumatra some 120 km from the main island Bengkulu and Bengkulu Bay.

Kalimantan: Tarakan and Wlnju Islands, Belikpapan, Pasir, Pulau hut, in the vicinity of Kotabaru, Kendawangan, 40 miles south of Ketaparw (south-vest Kalimantan) . Sulawesi : Sangihe Talaud (a group of islands between Sulawesi and the Philippines). Kema, Makupa (20 km south of Menado), Belang, Bay of Tolitoli. Along the west coast of (north coast of the Gulf of Nandar, Supa, Barru, Pangkadjene, Tabalar), Spermonde Islands, Djeneponto , Euiukumba , Sindjai , Bone, east coast of the Gulf of Bone (vicinity of Kalaka), east coast of Ikum Island,and south east coast of Buton.

Java:

West Java : Along the west and north coasts of this province with detail localities as follows: Tanimbang, Labuhan, Mauk, district of Rengasdengklok (TJemara, Sungai Euntu) , district of Pamanukan, Tjilcampek, Indramaju,and Tjirebon.

Central Java: Pekalongan district (from Brebes to Wileri,-about 210 km). Semarang regency (east of Kendal, Semarang, north-west of ~emak),Djepara district (Mlonggo, Keling), Pati regency (Taju, Margojoso and Wuhseti). Rembang district (Kaliori, Rembang , Sluhe , Kragan , Sarang ) .

East Java: Tuban, Surabaja regency (Udjung Pangkah, Bawean Island), Pasuruan regency (Grati), Probolinggo, Panarukan, Banju- wangi, Bjember regency (Puger, south coast of East Java) (west and east part of the north coast), east coast, central and east part of the south coast, Sapudi and east of Madura, Puteran Islet close to the south-east coast of Madura Island, Salembu Islet (between Madura and Knlimantan).

Lesser Sunda Island:

&&: Along the south-east and south-west coast of the island, north coast (west of Wlleleng) . - : Central part of the west coast, north coast (Tandjung, Djambianom) and along the south-east coast of the island (Iabuan Hadji) .

Sumbawa : Bay of Saleh and Bima (north coast), bay of Sape (east coast), and along the coast of Komodo Island.

-Timor : Bay of Kupang and close to Betu Putih.

(c) The occurrence of mature spawner of milkfish

Large shoals of big milkfish are often observed and some specimens with developed ovary or mature eggs are incidentally caught in certain places by fishermen.

The shoals often demonstrate an acrobatic jumping activity, which may indicate that spawning takes place in these areas. It is reported that such ahoals are mostly found in the sea not far away from the fry ground where the water is clear and the bottom consista of sand or coral. Localities where such shoals are often observed are listed as follows: Fig. 1 Eel distribution in south-east Asiatic seas (after Bertin, 1956)

Note their absence from coasts verging on the continental platform (horizontally shaded); and the extension of the Japanese eel as far as Tonkin (oblique shading) (after Schmidt and Delsman) I. (0.25-2 miles) along the coastal waters of Blang Lantjang, Udjwc Blang Hagu, Lhokseumawe, Krueng Mano.

2. Vest Java: 3-12 miles off Rengasdengklok, Indramaju and Tjirebon coast.

3, Central Java: About 6-12 miles off the coast of Pekalongan, Djepara and Taju. The appearance of big shoals are also often ob erved by fishermen around the island of Karim Djawa.

4. East Java: North-east of Madura Island, Madura Strait,and also at the Indian Ocean close to the south coast of the islands of Eiali.

5. Lombok: North coast of Lombok.

6. Kalimantan: Off Ketapang coast.

7. Sulawesi: Makassar-Strait (~permondeIslands) and Gulf of Bone between Siwa and Kolaka.

4.1.2 spp.

There are some 20 species of &&& found in Indonesian waters (Weber and de Beaufort, 1922). Among them Mugil dusumieri .is the most dominant species in the brackish water ponds. No reliable data concerning the population dynamic and habitat of this group are available.

They are common inhebitants of some rivers in Kalimantan an& some lakes (e.g.r Lakes Sidenreng and Tempe in south ~ulawesi). In the milkfish pond this species ranks immediately after milkfish.

The seed gets into the pond, together with other species, during high tide and grows up the& to marketable size.

4.1.3 Anmilla spp.

There are at least three species of Anmilla in Indonesian waters (~ertin,1956):

--A. bicolor A. marmorata &. celebensis

A. bicolor is the dominant species found on the island of Java.

Habitat: Coastal waters, estuaries, rivers, creeks, rice fiel&,and lakes.

Distribution: It inhabits rivers, creeks,or even rice fields, connected to open deep sea such as those found along the west and south coasts of Sumatra, Java, Eiali and Lesser Sunda Island bordering the Indian Ocean, and rivers along the east coast of Kalimantan and west coast of Sulawesi.

On the island of Java Anmilla are found in the regency, districts, or sub-districts listed below:

- Pelabuhanratu: Tjimadja, Tjitepus, Tjihaur - Serang : Tjibanten - Tasikmalaja : Tjitanduj, Tjiwulan - Tjiamis : Tjitanduj - Pagelaran : TJidjampang

Tjikaengan, Tji Sanggiri, Tji Baluk, Tji Laki, Tji Laju, Tji Rantjong, Tjikandung. - Bandjarnegara: R. Seraju and its branches - Jogja : R. Progo, R. Opak and Oja - Ikloran a. Progo, R. Tinggal - Karanganjar : can be found anywhere - Kraksaan : R. Pandanlaras, K. Rondoningo - Iragelang : R. Progo, R. Elo, R. Gending - Parakan R. Progo and its branches - Patjitan : R. Grindu and its branches R. Lorok and Sukoredjo - Temanggung : R. Progo

4.2 Crustacea

4.2.1 Penaeid vrawns

There are six species of penaeid shrimps and prawns, which occur in milkfish ponds. Gut of them four are of commercial value (m-, E. merbwensis, -M. mnoceros and g. brevicornis). The fry of Meta~enaeusaffinis, Para~enaeovsis gracillima and Parapenaeo~sisstvlifera, though quite often present as dominant species along the coastal waters close to the brackish water pond area, never enter the ponds. This fact gives clear evidence that their natural habitat is the open coastal waters.

Those six l%ambakltspecies prefer brackish water to grow up to marketable size. They prefer soft mum bottom with abundant benthic blue-green algae as their main natural food.

Data concerning the distribution of the fry is still restricted to the single species, i.e., E. monodon, since it is the only species which has already been deliberately cultivated. The fry of this species is distributed along the coastal waters where chanos fry are normally caught. Pangkadjene in south Sulawesi, Rembang in central Java,and Tuban in east Java are places where commercial collecting of fry'takes place.

Habitat: Rivers and swamps which are connected to the sea. The juvenile inhabits the lower reaches of the river, whereas the adult occupies the upper pardof the river, very often penetrating hundreds of km upstream.

Distribution: It can be found abundantly in big rivers such as:

- -Sumatra (R. Inderagiri , R. Batanghari , R. msi and Komering , R. Mesudji, R. Tulang BawaM).

- Kalimantan (R. Kapuas, R, Barito, R. Mahakam, R. Berau, R. SesaJap).

-Java (R. Tjitanduj, R. Seraju, R. Tjimandiri). The occurrence in other rivers is also reported.

- Sulawesi and Lesser Sunda Island This species occurs throughout these islands. The geographical distribution in the country and that according to the type waters is reported by Djajadiredja and Sacaan (1955) 5. EXPLOITATION

5.1 Chanos chanos

Among those species representing the natural resources of the coastal waters, chanos fry is an example which has already been intensively used since existence of the brackish water ponds hundreds of years ago.

Table I11 shows the production of chanos fry in 1970 from different provinces of Indonesia.

TABLE 111 Production of milkfish fry; Indonesia, 1970

Number of fry Province ( x lo3) Note Chano s Prawn Atjeh 41,220 x x Number of fry caught West Java 24,476 x unrecorded. Central Java 10,065 500 East Java 173,950 x Ehli 4,052 - - Still no catching 280 - activity. %st Nusa Tenggara - - East Kalimantan 182 - North Sulawesi x x South Sulawesi 117,973 3,450 South-east Sulawesi 750

TOTAL 372.948 3.950

Some fishing grounds are still under or unexploited. Fry.grounds are among others listed as follows :

Kupang - East Nusa Tenggara Province Batu Putih

Kema Nakupa - North Sulawesi Province Belang

Tolitoli - Central Sulawesi Province Bone - South Sulawesi Province and - West Nusa Tenggara Province a part of ionbok

In 1949, 2 ha of brackish water ponds in Atjeh were stocked with cephalus (Saanin, 1955). Stocking of milkfish pond with mullet fry has also been done for years in Djegara, central Java. KO t-eport is available, however, concerping the crop from those rearing.

Generally speaitJng mullet can be found almost in every pond, at any season, and is second in finfish production of the tambak. The fry of this euryhaline fish is distributed along the coastal waters and is quite often aggregated into great shoals specially around the estuaries and in the rivers. Collection of the fry and fingerling does not need vely special techniqdes. It is simply caught by means of a moderate-size scoopnet. The catch is then transferred to a small canoe for keeping and transportation.

Collection of mullet fry from natural waters for stocking in the milkfish pond needs to be intensified in the fuzure.

It has recently been felt that the chanos fry stock is far from sufficient and that at present the price of the chanos fry is becoming too high in comparison to the price of the marketable size chanos.

5.3 Lates calcarifer -Lates calcarifer is a highly priced fish which has a good market demand. It may be found in the milkfish ponds and in the rivers up to I00 km from sea. This species is being cultured on an experimental scale in India, Pzkistan, Singapore, and on a small scale in Thailand and Vietnam where it is fed with small fishes and shrimps.

Rearing of this carnivore fish together with cheap and prolific species,such as tilapia, may give more profit.

The need of elvers is estimated at 30 tons annually in Taiwan and only 10 tons can be obtained co qua culture Bull. 72). A certain source in Japan (personal communication) informs us that only 30 tons of the 50 tons of the annual demand of glass eel in Japan could be furr-ished.

The serious situation of the stock of elvers in those eel-producing countries (Japan and Taiwan) and the strong world market of eel is a greaz stimulating agent for the country to become aware of its abundant resources.

Surveys on the distribution and abundance of the species,as well as experiments on methods of capturing elvers and silver eel and culture nanagement,were started early this year.

5.5 Penaeid shrimr, and vrawn

It is estimated that in 1971 the brackish water ponds throughout the country produced from 8,500 to 12,500 tons of penaeid shrimps and prawn. Until recently the culture of shrimps. has been conducted in the traditional manner.

The increasing foreign and domestic trend for increased demands of shrimps and prawns (Table IV) has stimulated farmers to improve their culturing techniques. In some provinces such as south Sulawesi, central and east Java, the collectior. of "udang windu" (P. monodon) seed has been a routine activity during the season. Rearing of udang windu, together with chanos or as monoculture,has been conducted in those areas during the past few years.

TABLE IV Total volume and value of export of frozen and dried shrimp (marine and brackish water)

1968 1969 1970, 1971'I ) frozen dried frozen dried frozen dried frozen dried Quantity (tons) 2,262 334 4,257 334 5,687 258 5,721 96 Value US $(OOO) 663 84 759 62 3,629 50 4,790 14 (X 1,000) (1) The figure for 1971 is the total volume of export up to June 1971 only. Wing 1970-1971 the brackish water pond shrimps represent 40-6016 of.the total amount of shrimps exported.

5.6 Macrobrachium rosenber~ii

Althoygh the adult of this species inhabits freshwater (rivers and swamps), it is worth listing here since the larvae of this species occupy estuaries and brackish water zones. The abundance of the population in the rivers is greatly influenced by the survival of the post larvae which undergo metamorphosis into juvenile in the estuarine and coastal water regions.

Halvest of this Species to meet the local demand has been carried out for a long time (R. Ogan Komering, R. Yhhakam, R. Beran,and R. Seraju). Since early this year foreign market demand of this species has remarkably increased and the price of this prawn has become almost equal to the price of peneeid prawns.

To assess the real potential and abundance of the natural stock, surveys of rivers and open waters in Kalimantaa, south Sumatra,and ~iauare being conducted.

5.7 Scylla serata (mangrove crab)

The occurrence of mangrove crab is common in the brackish water ponds and mangrove swamps.

Though the culture of young crab to marketable size is being done in a moderate scale in some Asian countries such as Taiwan and Singapore, no such activity iwcarried out in Indonesia.

The production of this crab for daily supply in local markets comes from catches of natural stocks. Approximately 3-4 kwintals are delivered daily from Kroja district for consumption at Bandung and Djakarta. Only a part of the mangrove swamps in Bone (south Sulawesi) has been exploited and other areas, mainly on the islands outside Java, have not yet been exploited.

The following four out of nine species of Ostrea are commonly found in Indonesian waters:

1. Ostrea cuculaQ 2. Ostrea forskali 3. Ostrea cristanalli 4. Ostrea hvotis

On the island of Madura oysters are comon in the diet of the inhabitaxs. Along the coast of Java they are also collected, though in small quantity. It has been reported that oyster culture on a small scale has been in existence since 1957, in Asahan (east Sumatra ) , Tjilatjap (south coast of central Java) and Djepara (north coast of central Java).

The production of oysters is rather limited, ranging from 0.5-15 kg of meat per man day. Along the coast suitab1,esites for spawning and culture are available. Though there exists a potential for development, the culture of this mollusc, with the limited market demand, is unde~elopedin Indonesia. Once the demand exists, the culture activity may be increased.

5.9 Anadara aranosa

Cockle, though not presented in the daily menu of the Indo:.esian people, can be found almost in any market of the coastal town. An average of 500 kg is at this time being consumed,every day in restaurants of Djakarta. Anadara panosa occurs abundantly on tidal flats mainly around the estuaries of big rivers where thick vast layers of soft mud rich in organic matter, is formed due to siltation processes.

Such habitats having a great comentration of Anadara are found at the following localities:

- Sumatra : along the east coast of Sumatra, ranging from R. Asahan estuary in the north up to Ogm Komering in the south.

- Java : along the north coast of Java (Krondjo, Mauk, Tjilintjing, Krawang, ~jepara)and south coast of Java (T jilatjap) .

\ - Kalimantan : along the east coast of Kalimantan, ranging from Kajan River and around Tarakan Island in the north and Samarinda in the south.

A small scale culture in an enclosed area with seed stocking has been in operation since 1966.

6. PROSPECT FOR FUTW DEVELOPMENT

It is a general belief in fisheries circles in Indonesia that among fisneries resources which the country possesses, coastal waters offer the most feasible prospect for rapid economical development.

The above describcir potentials may be divided into those resources that have already been in use and those that ?.;.?lain untouched. Mllkfish and penaeid shrimps could be developed by expanding the culture ids and through intensification programmes.

Table I shows estimates of the available sites suitable for pond construction. This relates only to thosn of which the realisation will take place soon. Schuster (1949), however, mentions a total area of 6 million ha available for pond construction throughout the country. The island of Sulawesi may in this case fall into the focus for immediate development.

Comparing the production levels gained on experimentalscalesin Indonesia (Djajadiredja and Purnomo, 1970) and those in Taiwan (Lin, 1968) there are still many possibilities to increase fish production of brackish water ponds in this country.

tlYmssguidance intensificationt1campaigns, which have been launched In many localities (south Sulawesi, central and east Java) in the field of chanos as well as shrimp culture, have resulted In a significant increase of production, to as much as 700-1000 kg/& year. These levels can still be improved to 2000 kg/ha year. High yields of chanos could be obtained by application of organic and inorganic fextilisers in the right manner, accompanied by intensive eradication of undesirable fish.

In the field of shrimp culture successful experiments on breeding of penaeid shrimps conducted at Makassar (south Sulawesi) open the possibilities for intensifyin@: shrimp culture with controlled stocking manipulation. Although still in pilot-operations stage, seed of Penaaus -, g. gemisulcatus and P. mer~ensishave already been distributed to farmers. On the other hand collecting of shrimp larvae becomes a more common practice in south and central Java. The export of frozen shrimp during the past three years has been increasing (vide Table N). The amount exported in 1971 (up to June) was 5,721 tons (up to September 1971 the volume was 10,855 tons) at a value of US$4,790,241, constituting respectively 46.2% and 72.4% of the total export volume of marine products. Out of this, brackish water pond culture contributes 40-6096. It is expected that shrimp culture should become more and more important in the near future, and will attract more interest of domestic as well as foreign investors. To attune to this increasing interest,increasing stutlies, experiments,and pilot operations have to be conducted. For this purpose a Research Centre is being constructed in central Java.

The prospect of developing the culture of other cultivable species, such as eel, mangrove crab,and macrobrachium seems to be most promising, considering the increasing demand from the markets for these species.

7. PROBLEMS

Problems confronting the aquaculture development of Indonesia are many. Capital marketing, infrastructure, etc., are the most difficult ones to be overcome.

The already utilised resources of various kinds of larvae, essential for the development of the coastal aquaculture industry,need to be protected. Establishment of industries, growing population, use of pesticides for agricultural purposes along the coast, may all cause pollution of the coastal waters which in turn will affect the resourcesin the area. Misuse of toxic material and explosives for the purpose of catching fish has been reported. The increasing use of modern craft and gear,installarionof lift nets with light (bagan) and fish traps in coastal waters are among other problems which need to be considered in the management of the resources of the coastal waters.

Bertin, L. Eels. Cleaver-Hume Press Ltd, London. 1956

Djajadiredja, R., and Purnomo, A. Requirements for successful fertilisation in increasing 1970 milkfish production.

Djajadiredja, R., and Sachlan, #. Shrimp and pram fisheries in Indonesia with special reference to the Kroja district. Paper presented at 6th Session, 1955. IPFC/55/SYM(14): 333.

Lin, S.Y. Milkfish farming in Taiwan. a review of practice and problems. Fish 1968 Cult.Rep.Taiwan, (3):63 p.

Saanin, H. Some notes on the occurrence of Chanos fry in Indonesia. Berita 1953 Perikanan 1953.

Brackish water culture outside Java. 3rd FAO/ETAP. IPFC-55-Lac. 1955 5. 6, 10:5.

Schuster, W.H. Over der mogelijkheden ener Oester Cultuur in Indonesia. Landbow 21, 1949 NO. 1-2, p. 33-42.

Weber, M.,and de Beaufort, L.F., The fishes of the Indo-Austr_alianArchipelago. Vol.IV. E.J. Brill 1922 Ltd., Leiden.