 | Lates calcarifer |
CULTURE PRACTICES
There are at present 70 floating fish farms, covering 35 out of 300 hectares of the available coastal seafarming area in Singapore. The total seafarming production in 1988 was 1,973 MT of which 23.9% derived from finfish mostly seabass (11.9%). Seabass is the most popularly cultured finfish in Singapore. Culture is done in floating netcages made of a simple wooden frame kept afloat by plastic buoys. A single farm is typically 1,500 m2 anchored in a water space of 5,000 m2. Netcages vary in dimension, however typical ones measure 2×2×2 m or 3×3×2-3 m or 5×5×2-3 m. Fingerlings are mostly purchased from Thailand and the Philippines, however a number of local hatcheries have recently been set up. Fingerlings of 2–5 grams are initially stocked at 100–150/m2 and then reduced to about 44/m2 when they have attained a body weight of 80–100 grams. Seabass are fed on chopped fresh trash fish and the Feed Conversion Rate (FCR) is typically around 5–7:1. Research studies on formulated feeds are being conducted by the Government. Culture period is 6–8 months when the fish have attained a body weight of 600–800 grams.
PRODUCTION
HISTORY
Coastal seafarming started in 1970 and originated from palisade trapping (kelongs) where fish got captured with lift nets. Seabass specimens which were of commercial size were sold immediately, while under-sized ones were stocked into fixed holding cages suspended from the kelongs or by floating wooden frames. These fish were raised to marketable size on trash fish trapped in the kelongs. Since the implementation of the Marine Fish Farming Scheme in 1981, aquaculture techniques have improved and larger and more sophisticated floating netcages came into operation. Production in 1987 was 235 MT.
TOTAL REGIONAL PRODUCTION
STATUS OF CULTURE
| TOPIC | SPECIES |  |
| Lates calcarifer | ||
| Source of seed | Artificial and wild (imported) | |
| Culture method | Floating netcage | |
| Yield/ha | 46 MT/ha | |
| Market | Domestic | |
| Production area | 35 ha | |
| Status of culture | Developed | |
| Major constraints | Limited labour | KEY MAP |
 | Epinephelus tauvina |
CULTURE PRACTICES
There are at present 70 floating fish farms, covering 35 out of 300 hectares of the available coastal seafarming area in Singapore. The total seafarming production in 1988 was 1,973 MT of which 23.9% derived from finfish out of which 7.2% was grouper. Culture is done in floating netcages made of a simple wooden frame kept afloat by plastic buoys. A single farm is typically 1,500 m2 anchored in a water space of 5,000 m2. Netcages vary in dimension, however typical ones measure 2×2×2 m or 3×3×2-3 m or 5×5×2-3 m. Fingerlings are mostly purchased from Thailand, Malaysia and Indonesia. Fingerlings of 2–5 grams are initially stocked at 100– 150/m2 and then reduced to about 44/m2 when they have attained a body weight of 50–100 grams. Groupers are fed on chopped fresh trash fish at 3–10% body weight depending on their growth stage and the Feed Conversion Rate (FCR) is typically around 5–7:1. Research on formulated feeds are being conducted. Culture period is 6–8 months when the fish have attained a body weight of 600–800 grams. Major constraints affecting this seafarming activity are shortage of labour and fry and trash fish supply.
PRODUCTION
HISTORY
Coastal seafarming started in 1970 and originated from palisade trapping (kelongs) where fish are captured with lift nets. Grouper specimens which were of commercial size were sold immediately, while under-sized ones were stocked into fixed holding cages suspended from the kelongs or by floating wooden frames. These fish were raised to marketable size on trash fish trapped in the kelongs. Since the implementation of the Marine Fish Farming Scheme in 1981, aquaculture techniques have improved and larger and more sophisticated floating netcages came into operation. Production in 1987 was 129 MT.
TOTAL REGIONAL PRODUCTION
STATUS OF CULTURE
| TOPIC | SPECIES |  |
| Epinephelus tauvina | ||
| Source of seed | Wild (imported) | |
| Culture method | Floating netcage | |
| Yield/ha | 44 MT/ha | |
| Market | Domestic | |
| Production area | 35 ha | |
| Status of culture | Developing | |
| Major constraints | Limited fry supply High cost of fry Limited labour | KEY MAP |
 | Lutjanus johni |
CULTURE PRACTICES
There are at present 70 floating fish farms, covering 35 out of 300 hectares of the available coastal seafarming area in Singapore. The total seafarming production in 1988 was 1,973 MT of which 23.9% derived from finfish of which 2.5% was snapper (Lutjanus johni). Culture is done in floating netcages made of a simple wooden frame kept afloat by plastic buoys. A single farm is typically 1,500 m2 anchored in a water space of 5,000 m2. Netcages vary in dimension, however typical ones measure 2×2×2 m or 3×3×2-3 m or 5×5×2-3 m. Fry are mostly from Malaysia and Indonesia. Fingerlings of 2–5 grams are initially stocked at 100–150/m2 and then reduced to about 44/m2 when they have attained a body weight of 80–100 grams. The cultured fish are fed on chopped fresh trash fish and the Feed Conversion Rate (FCR) is typically around 5–7:1. Research on formulated feeds are being conducted by the Government. Culture period is 6–8 months when the fish have attained a body weight of 600–800 grams. Major constraints affecting the expansion of snapper culture are shortage of labour and fry and seasonality of market demand and price.
PRODUCTION
HISTORY
Coastal seafarming started in 1970 and originated from palisade trapping (kelongs) where fish got captured with lift nets. Snapper specimens which were of commercial size were sold immediately, while under-sized ones were stocked into fixed holding cages suspended from the kelongs or by floating wooden frames. These fish were raised to marketable size on trash fish trapped in the kelongs. Since the implementation of the Marine Fish Farming Scheme in 1981, aquaculture techniques have improved and larger and more sophisticated floating netcages came into operation. Production in 1987 was 35 MT.
TOTAL REGIONAL PRODUCTION
STATUS OF CULTURE
| TOPIC | SPECIES |  |
| Lutjanus johni | ||
| Source of seed | Artificial and wild (imported) | |
| Culture method | Floating netcage | |
| Yield/ha | 44 MT/ha | |
| Market | Domestic | |
| Production area | 35 ha | |
| Status of culture | Developing | |
| Major constraints | Limited fry supply High cost of fry Limited labour | KEY MAP |
 | Perna viridis |
CULTURE PRACTICES
Mussels are farmed on ropes suspended from wooden rafts which are usually rectangular, with the long axis parallel to the tidal current. Mussel seed are collected from the wild and there is no attempt at broodstock management except through retention of a percentage of the on-farm grow-out population as broodstock. Spat are usually collected on 2 m long strips of old netting or nylon ropes. A settlement of 10 million spats per strip may be expected during a good spatfall. The ropes or netting strips on which the mussels are cultured are 2–4 m long and immersed at 4 ropes/m2. Each rope yields 40–60 kg shell-on marketable size mussels (6–8 cm) in 6–8 months. No thinning is practiced commercially as this has been found to be too time-consuming and labour intensive. The spat are allowed to thin out naturally. An estimated 10–15% of the spat attain the market size. No serious diseases or parasites have been observed. However, water stagnation in farming areas can lead to low dissolved oxygen and persistent rainfalls to low salinity levels. When the above situation occurs localised high mortalities can be observed.
PRODUCTION
HISTORY
Green mussel farming started some 14 years ago in the Johore Strait. Production has increased slightly from 978 MT in 1983 to 1191 MT in 1988, an increase of 22% over the last 5 years. There are now about 5 hectares under cultivation, however total potential culture sites have been estimated at 300 hectares. Mussel spat are collected from the wild; spatfalls occur throughout the year with two major peaks. Main culture sites are presently located in the West Johore Strait. Depuration is not commercially practiced, however feasibility trials are being conducted by the Primary Production Department.
TOTAL REGIONAL PRODUCTION
STATUS OF CULTURE
| TOPIC | SPECIES |  |
| Perna viridis | ||
| Source of seed | Wild | |
| Culture method | Raft | |
| Yield/ha | 15 – 20 kg/m rope/6 – 8 months | |
| Market | Domestic | |
| Production area | NA | |
| Status of culture | Developed | |
| Major constraints | Environmental pollution Labour intensive Limited labour | KEY MAP |
 | Penaeus merguiensis |
CULTURE PRACTICES
Banana shrimp culture density in floating netcages is from 300– 600/m2. Postlarvae 25 days old (PL25) reach the marketable weight of 12 grams in 5 months. About 2 kg/m2 yield is obtained per cycle or 30 MT/ha productive area/annum, which is about 6 times the yield from conventional pond culture. Shrimp are fed commercially available formulated dry feeds which are either imported or produced locally. Trash fish and mussels are also used. Diseases caused by Vibrio spp., chitinoclastic bacteria and Hepatopancreas Parvo Virus (HPV) occasionally occur as a result of the intensive culture. Vibrio diseases are curtailed by oral therapy, while there is no direct treatment for the other two. Antibiotic baths are made to prevent secondary bacterial infections. Major constraint affecting shrimp culture in Singapore is the limited availability of culture sites. A further constraint to shrimp breeding is the dependence on wildcaught spawners. The Primary Production Department has initiated a collaborative programme with the National University of Singapore and the Danish Aquaculture Institute to close the spawning cycle of tiger and banana shrimps.
PRODUCTION
HISTORY
Banana shrimp (Penaeus merquiensis) culture in Singapore is mainly practiced in earthen ponds although netcage culture is also being carried out. In the near future shrimp will be most likely produced intensively on land-based culture systems (e.g. raceways) such as the ones being established in Loyang Agro-technology Park. Over the last 5 years (1983–1988) production has increased from 4 MT to 30 MT with a peak production of about 35 MT in 1986. Shrimp production in 1988 accounted for 1.5% of the total national seafarming output.
TOTAL REGIONAL PRODUCTION
STATUS OF CULTURE
| TOPIC | SPECIES |  |
| Penaeus merguiensis | ||
| Source of seed | Artificial | |
| Culture method | Pond, raceway and floating netcage | |
| Yield/ha | 30 MT/ha/yr | |
| Market | Domestic | |
| Production area | 190 ha | |
| Status of culture | Developed | |
| Major constraints | Limited areas available | KEY MAP |
 | Panilurus polyphagus |
CULTURE PRACTICES
The spiny lobster is cultured in floating netcages similar to the ones used for finfish culture. A floating netcage is made of a simple wooden frame kept afloat by plastic buoys. Netcages vary in dimension, however typical ones measure 2×2×2 m, 3×3×2-3 m or 5×5×2-3 m. Most nettings are made of synthetic fibres as they are relatively easy to handle, install and remove. Synthetic fibres are also preferred over artificial ones (e.g. cotton) because of their durability and strength. Polyamide and polyethylene netting are readily available. The latter material is usually preferred because it is cheaper and protects better against damage caused by crabs and fish. Due to biofouling (e.g. barnacles, tunicates, algae, etc.) the netcages have to be regularly changed. Wild-caught juvenile lobsters with mean body weight of about 100 grams are stocked at 15/cu m (30/m2). The marketable size of 250–300 grams is attained in 3–4 months. Production per cubic meter is around 45 kilogrammes. The lobsters are fed daily on chopped trash fish and mussels.
PRODUCTION
HISTORY
The culture of the spiny lobster Panilurus polyphagus is a relatively recent introduction to the floating netcage system. The survival of wild-caught lobster juveniles and their growth rates have been encouraging. Over the last 5 years (1983–1988) production has increased from 6 MT to 24 MT. Lobster production in 1988 accounted for 1.2% of the total national seafarming output. Lobsters are usually cultured by individuals who are also involved in seabass and grouper culture. The rearing facilities are placed at the same location.
TOTAL REGIONAL PRODUCTION
STATUS OF CULTURE
| TOPIC | SPECIES |  |
| Panilurus polyphagus | ||
| Source of seed | Wild | |
| Culture method | Floating netcage | |
| Yield/ha | 45 kg/m3 | |
| Market | Domestic | |
| Production area | NA | |
| Status of culture | Developed | |
| Major constraints | - | KEY MAP |
 | Scylla serrata |
CULTURE PRACTICES
Crabs are fattened in floating netcages constructed with iron mesh and covered with polyethylene netting. The sizes of the netcages vary, however typical ones measure 1×2×1 m, 2×2×1 m or 2.5×2.5×1.2 m. The top of the cages are covered by a netting in order to prevent the crabs from escaping. Crab fattening is usually carried out by fish farmers as an additional source of income. Stocking density is at 9 kg/cu. m (35–40 specimens) or 10/m2. During the fattening period of 10–20 days the crabs are fed with chopped trash fish; weight gain is minimal. Mangrove crab culture has progressed from incidental farming into a contracted activity where farmers arrange to receive and fatten the animals for the local market according to the seasons of crab availability. Major constraints affecting this seafarming activity are: shortage of labour, unstable supply of crabs and high mortality.
PRODUCTION
HISTORY
Mangrove crabs (Scylla serrata) are not cultured in the strict sense of the word as they are collected from the wild as adult specimens and placed in floating netcages for fattening and shell hardening. All of the crabs imported into Singapore come from Malaysia and Indonesia. Out of the 35 hectares being used by the seafarming industry, 5 are employed for crab farming. Over the last 5 years (1983–1988) production has increased from 163 MT to 256 MT with a peak production of 330 MT in 1987. Most of the crab production comes from the East Johore Strait (178 MT).
TOTAL REGIONAL PRODUCTION
STATUS OF CULTURE
| TOPIC | SPECIES |  |
| Scylla serrata | ||
| Source of seed | Wild | |
| Culture method | Floating netcage | |
| Yield/ha | 9 – 10 kg/m3 | |
| Market | Domestic | |
| Production area | NA | |
| Status of culture | Developed | |
| Major constraints | - | KEY MAP |
