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REVIEW OF COASTAL WATER RESOURCES IN RELATION TO COASTAL AQUACULTURE R. Djajadiredja and A. Purnomo, Inland Fisheries Research Institute, Bogor, Indonesia. 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 Lesser Sunda Islands, 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 East Java 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 south Sulawesi (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) Madura Island (west and east part of the north coast), east coast, central and east part of the south coast, Sapudi and Kangean Islands 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) . -Lombok : 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.