Grouper Culture and

A Review of the Grouper Breeding Programme in Singapore


T. M. Chao and R. Chou[1]



There are 84 commercial floating fish farms in Singapore, located in the coastal waters of the East and West Johor Straits. These farms are responsible for 3,554 tonnes of aquaculture products valued at S$13.5 million (US$9.6 million) in 1995.  Mainly estuarine (Epinephelus tauvina), brown-marbled (Epinephelus fuscoguttatus) and malabar (Epinephelus malabaricus) groupers are among the more popular marine food fish cultured. Grouper species consists of 12.5-3.3% of total production tonnage and 31-19.9% of the total value for 1991 to 1995. The reductions in production of grouper over the years have been possibly due to the decrease in supply of fry and fingerlings from the wild. The emergence of seabass as the good alternative for restaurant fish could be another reason contributing to a decline in grouper production. This paper describes how grouper is commercially farmed in Singapore and the research efforts made with grouper species, initiated since 1971, which has made incremental progress in broodstock management and larviculture zootechniques. The recent major achievement from a three-year grouper breeding programme between Primary Production Department and National University of Singapore and sponsored by the National Science and Technology Board was the isolation and purification of gonadotropins and growth hormone from estuarine grouper pituitaries. Mass cloning of these purified hormones is expected. It is envisaged that the application of these cloned hormones in near future would improve the spawning performance and eventually larval survival of estuarine grouper.



Singapore, an island state with a territory covering 646.1 km2 and a population of 2.98 million people, is situated approximately 136.8 kilometres north of the equator. It is in the centre of Malayan Archipelago and at the crossroads of the Pacific and Indian Oceans. Due to the scarcity of land, the focus on agriculture is on the development of intensive farming systems and at maximising production and economic returns per unit area or effort. The farming of marine food fish in floating net-cages was identified in early 1970s as a suitable intensive farming system to supply fresh and live fish in Singapore.

The Primary Production Department (PPD) initiated research on marine fish aquaculture in Singapore in 1971. Since then, several marine food fish species were studied with the aim of achieving constant and sufficient seed supply for the marine fish aquaculture industry.  The species studied are: estuarine grouper or greasy grouper, Epinephelus tauvina or Epinephelus coioides; polkadot grouper, Cromileptes altivelis; seabass, Lates calcarifer; golden snapper, Lutjanus johnii; brown-marbled grouper, Epinephelus fuscoguttatus; the mangrove red snapper, Lutjanus argentimaculatus; and four-finger threadfin, Eleutheronema tetradactylum (Chen  et al., 1977; Lim  et al., 1986; Lim  et al., 1985; Lim  et al., 1990; Lim and Chao, 1993; Chao  et al., 1994). This paper will address the culture of grouper and research and development efforts on its breeding in Singapore.

Commercial Net-cage Grouper Farming

The Marine Fish Farming Scheme was introduced by PPD in March 1981. Since then, the marine fish aquaculture industry in Singapore has grown from 32 to 84 licensed net-cage fish farms in 1995. The annual marine aquaculture production has increased from 2,191 tonnes in 1991 to 3,554 tonnes in 1995 (Annex 1). In 1995, these 84 net-cage fish farms occupying 46.5 ha of the coastal area in the Johor Straits (Annex 2), produced 3,554 tonnes, valued at S$ 13.5 million (US$ 9.6 million, at US$ 1.00 = S$1.40).  This accounted for about 98% of the total aquaculture production of 3,625 tonnes. The 5-year marine aquaculture production is shown in Annex 2. Grouper species consists of 12.5-3.3% of the total production tonnage and 31-19.9% of the total value over the 5-year period. Although the total annual production and value of grouper in relation to the overall farm's production have declined over the years, the ex-farm price of grouper is still quite stable (at S$20-22 per kg or US$ 14.3-15.7 per kg). The decrease in the seed supply of grouper could be the main reason for the production decline. The emergence of seabass as the good alternative for restaurant fish in Singapore could be the other reason.

Species of Groupers Farmed in Net-cage Farm

The estuarine grouper is the main species of grouper farmed in floating net-cages. Other minor grouperspecies are brown-marbled grouper, malabar groupers (Epinephelus malabaricus), the coral trouts (Plectropomus maculatus and P. leopardus) and polkadot grouper (Cromileptes altivelis).

The groupers are selected for their high market value, especially when sold live to the market. The other important criteria for farming grouper are: tolerance to high stocking densities at 16 fish/m3 or 40 fish/m2; expectation of yields of about 16 kg/m3 or 24 kg/m2; fast growth (6-8 months per cycle); and availability of seed supply, albeit seasonal.

Farm Design

The basic farm design for marine food fish, introduced by PPD in the 1970s, is suitable for grouper culture. The design consists of a net-cage proper and a wooden raft from which the net-cages are suspended. The wooden raft is made up of wooden beams, assembled into lattices and kept afloat by about 350-400 plastic drums, each of 250-300 litre capacity. Polyethylene net-cages varying from 2x2x2m (deep) to 5x5x3m (deep, 8-50 mm in mesh size) are suspended from the frames. Net-cages are generally classified according to mesh sizes: hapa (8 mm mesh size, knotless nylon), nursery (25 mm mesh size, polyethylene) and production (50 mm mesh size, polyethylene). Adjacent to the floating frame is a wooden work hut and platform for feed preparation and storage of equipment and materials. The farm (frames and hut) occupies about 1,500-2,000 m2 (about 30-40%) of the half hectare (5,000 m2) of sea space that PPD leases out to the farmer at S$650 (US$464) per year. The present fish farms still generally follow this design as shown in Annex 3.

Farming Methodology

The grouper farming method is quite straightforward with a somewhat fixed sequence of events per culture cycle (Anon., 1986). Grouper fingerlings, 75-100 mm in total length obtained either from natural catches locally or more usually imported, are stocked initially at 100-500 fish/m2 of net bottom area into hapa nets. The grouper fingerlings are usually held in the hapa for a month or so until they attain 125-150 mm in total length, when they would be thinned out to nursery nets at about 44 fish/m2. Subsequently, after 2-3 months they are transferred to production net and grown until market-size of 600 to 700-g body weight when they are harvested. At the time of harvesting, that is 6 to 8 months from stocking in the nursery net, groupers would have thinned themselves out naturally, with a natural mortality of 5-10% to about 40 fish/m2. By manipulating the management of stocking and feeding, a farmer can have a continuous batch of fish produced throughout the year.

Net-cage farmers still prefer to use trash fish as feed for grouper (Chou and Lee, in press). Trash fish is the by-catch of trawlers, comprising small fish of low economic value (S$500/tonne or US$357/tonne), like goatfish (Upeneus spp.) and jewfish/croakers (Pennahia spp.). Trash fish is chopped to smaller pieces before being fed to fish in the net-cages. Feeding rate is 10% body weight during the hapa stage, reduced to 8% body weight at the nursery stage and finally 5-3% during the grow-out stage. It is estimated that feed conversion ratio for grouper is 4.5:1. In some farms, semi-moist feed is prepared on-farm for groupers and other fishes, usually when bad weather limits the availability of trash fish from trawlers. The formulation for semi-moist feed is simple, comprising fishmeal (30%), corn gluten (70%) and vitamins and minerals (0.5-1%). Alternatively, the farmer will mix ground trash fish (30-50%) with a binder mix consisting of fishmeal, soya bean meal, rich bran, corn gluten or wheat flour, vitamins and minerals. The mixture is either hand or machine mixed with hot water to gelatinise the starch (Chou, 1995).

Harvesting of groupers is done manually by two farm workers. They lift the net-cage and gather the groupers and scoop them out into waiting transport tanks in boats that take them to shore for direct transfer to lorries and then to restaurants.

Disease Control

Disease of grouper species may arise for various reasons for example stress, parasites, pathogens and nutritional imbalance. Importation and handling mortalities are two instances where stress is directly involved. To control post-importation mortalities, farmers are advised to carry out sanitation by special arrangement with the fish fingerling agent in the country of origin, or the farmers themselves can perform it. Comprehensive sanitation protocols that includes pre-shipment, trans-shipment and on-farm sanitation are recommended to fish farmers for improving the health status of imported fish fingerlings (Chong and Chao, 1986; Khinet  et al., 1987). Pre-shipment sanitation requires the fish fingerling agent to treat the grouper with acriflavine (10 ppm) prior to dispatch. Trans-shipment sanitation involves the addition of 10 ppm of nitrofurazone to fish transport water. On-farm sanitation comprises a 100 ppm formalin bath of 1 hour, followed by a nitrofurazone (30 ppm) for 4 hours. Antibiotic prophylaxis, for example oxytetracycline at 0.5g/kg feed daily for 7 days, may further increase survival of sanitised fish, but itself is not as effective as chemical sanitation.

Protozoal diseases like cryptocaryoniasis caused by Cryptocaryon irritans commonly occurred in the hapa and nursery stages with groupers.  Estuarine grouper displays the classical ‘white spots’.  In certain cases, for example, with re-infestations or secondary involvement with bacteria, open ulcers are formed. Other protozoal disease agents occurring in groupers are Trichodina sp. and Brooklynella sp.  Due to difficulty in eradication of Cryptocaryon irritans, besides using chemical treatment, the farmers are advised to isolate sick fish and remove dead or terminally sick ones from net-cages and destroy them for the better control of cryptocaryoniasis on farms. The usual chemical treatment for protozoal disease is formalin (25 ppm) plus malachite green (0.15 ppm) for 12 hours.  Freshwater treatment for one hour may also help to combat the disease.  Other than protozoal disease, generalised ectoparasitic infestation by flatworms may occur, for example, Diplectanium sp. and Benedenia sp.  The latter is not an indigenous species, as there was no occurrence of this ectoparasite before the late 1980s.

Bacterial disease involves mainly vibriosis in grouper and can be controlled by oral administration of oxytetracycline (0.5g per kg feed) for 7 days. If the groupers are off feed, bath treatment of nitrofurazone (15 ppm) for at least 4 hours can be applied. In general, vibriosis is secondary in nature, occurring as a sequel to trauma or primary infection by protozoa. However, vibriosis probably accounts for a significant proportion of importation and handling mortalities. The two principal Vibrio species, V. alginolyticus and V. parahaemolyticus and several related strains have been isolated aseptically from sick groupers. None of them have been consistently identified with ‘vibriosis’, and artificial transmission of the disease, by injection into healthy fish, requires very high doses of bacteria.

Chong and Chao (1986) first described swim bladder syndrome in grouper as a fish disease of unknown aetiology. Chua  et al. (1993) reported the similar occurrence with CPE agent isolated from two outbreaks of the disease among grouper net-cage farms. A possible viral agent affecting the central nervous system was implicated. A novel disease occurring in estuarine grouper, called ‘sleepy grouper disease’ (SGD) was described by Chua  et al. (1994). The aetiological agent of SGD was provisionally identified as an iridovirus and probably introduced with imported groupers. Until a serological kit for early detection of carriers among the introduced grouper fingerlings is available, these diseases could only be controlled by isolation and removal of diseased fish or even a total eradication of the stock.

An RNA reovirus was isolated from spleen of coral trout (Plectropomus maculatus) with clinical sign of inappetence and lethargy, followed by death 2-3 days later. (Chew-Lim  et al., 1992). The controlling measure is the same as other viral diseases.

Varied degrees of lipidosis are observed in the livers of net-cage cultured groupers. This is a common nutritional disease among cultured food fish. It is thought that this phenomenon is linked to rancidity due to poor storage of trash fish and/or the use of trash fish with high fat content.

Review of Grouper Breeding Research in Singapore

Histological Study on Gonads of Wild Estuarine Grouper

Estuarine grouper is commercially one of the most important fish species and is a highly esteemed food fish in Singapore and Southeast Asia. Due to its economic value, the Coastal Aquaculture Unit of PPD initiated production study experiments on this grouper species in floating net-cages in 1971. However, the supply of fingerlings from the wild is limited and uncertain and the breeding biology of the fish was then investigated with the aim of mass-producing them under controlled conditions. Tan and Tan (1974) demonstrated that the grouper is a protogynous hermaphrodite through gonadal histological studies. They showed the biological minimum size of the grouper was 450-500 mm and that male fish had testes at around 740 mm in standard body length and more than 11 kg in body weight. Transitional gonads containing male and female gonadal tissues occurred in fish of 660-720 mm.

Breakthrough in Induced Spawning and Larviculture

Chen et al. (1977) reported on the breakthrough success of the induced breeding. Accelerating sex reversal of 3-year old females through hormonal manipulation mainly attributed it. The broodstock matured as females at the age of 2 years and at 412-500 mm in standard length. Administrating human chorionic gonadotropin at a dosage of 500-1000 IU (International Units) effected induced ovulation per kilogram of recipient fish. More effective results were obtained when extracts of pituitary glands of either white snapper or chum salmon were given in the final injection. The larval development and its feeding protocol were also described. Chen (1979) reviewed progress and problems in grouper culture. The large-scale grouper production was hampered by shortage of fingerlings and feeds (trash fish) in nursery stage, the inappropriate size of larval food organisms in the larviculture stage and cannibalism during metamorphosis and juvenile stages. Chao and Chow (1990) further reported the effect of methyltestosterone on estuarine grouper gonadal development. The technique to produce maleness in grouper by oral administration of 17a-methyltestosterone at a dosage of 1-2 mg/kg body weight at twice or three times a week was established and documented.

Development in Broodstock and Larviculture

Chao and Lim (1991) reviewed the problems and progress in the development of grouper breeding technology. The major problems were the supply of good quality eggs for larviculture and high mortality during critical periods in the larval stages. Several new techniques were also reported. These included a hormone implantation technique for inducing sex reversal in estuarine grouper and a natural spawning technique for brown-marbled grouper. The implantation technique could replace the former method of oral administration of the hormone capsule. A 2-mg liquid silastic capsule inserted into the abdominal cavity via an implanter is effective in transforming a mature female grouper of average 3-4 kg body weight to a functional male. 

Enrichment techniques to broodstock diets and live larval food with highly unsaturated fatty acids (w3-HUFA) to improve egg quality and larval survival were introduced from Belgium.  Dhert  et al. (1991) reported the broodstock diet enrichment technique that a commercial highly unsaturated fatty acids booster MARILA (Artemia System, N.V., Gent, Belgium) was injected into the abdomen of trash fish for feeding to grouper brooders at a dosage of 50 mg/kg of body weight at thrice a week.  This resulted in 21% increase of total lipid content of estuarine grouper eggs with % increase of the size of oil globule. This improved the larval survival by 5%. Following the same principles, enriched rotifers and Artemia nauplii, boosted with a commercial lipid emulsion (SELCO, Artemia System NV, Baasrode, Belgium) were used to feed grouper larvae.  It was found that the grouper larvae fed with these enriched larval live feeds could withstand the stress tests better than those fed on normal larval feeds.

The use of super-small (SS) rotifer as the first food and a refined zootechniques like addition of green algal water, covering of larval tank, water exchange by through-flowing and oil removal by triangular oil skimmers to overcome early mortality of the larvae have also been established (Chao and Lim, 1991 and Lim, 1993). With these advances in techniques, there were incremental improvements on the larval survival in various stages of larviculture. However, the overall larval survival of grouper was still very low (below 1%) and inconsistent.

Brown-marbled Grouper Versus Estuarine Grouper

Unlike estuarine grouper as described above, the brown-marbled grouper can spawn naturally in net-cages during the monthly lunar period from the last-quarter moon to just before the new moon (Lim  et al., 1990, Chao  et al., 1993). Lim (1993) compared the spawning and characteristics of the estuarine grouper and brown-marbled grouper. It was concluded that the brown-marbled was considered a better potential species than the estuarine grouper for large-scale production. The superior qualities of brown-marbled grouper for larviculture are: (i) the occurrence of natural spawning in net-cages;  (ii) higher egg production and all year round spawning capability; (iii) higher fertilisation rate and higher percentage in buoyant eggs; (iv) faster larval development and higher larval survival (Lim  et al., 1990, Chao  et al., 1993). However, the larval survival of brown-marbled grouper is also not consistent and well below 10%, which is not a level for commercial application. We should not ignore the potential of brown-marbled grouper based on the fact that the egg quality and larval survival are more superior and higher than that of the estuarine grouper. These qualities are definitely advantages for future commercialisation.

PPD-NUS Grouper Breeding Project Phase I (3 Years)

In order to look further into the problems of poor egg quality and larval survival in grouper, a three-year collaborative project between PPD and the National University of Singapore (NUS) funded by National Science and Technology Board of Singapore was initiated in 1992. The long-term objective of the project was to establish commercially applicable grouper breeding technology. However, the objective of the project from 1992-1995 was to look into basic aspects of grouper reproductive physiology at molecular and hormonal levels.

Studies on Sex-change and Pituitary and Gonadal Hormones

The sex reversal of the fish was further studied at molecular level by analysing in vitro metabolism of gonadal tissues. The steroidogenic potential of the gonadal tissue was also examined by in vitro metabolism before and after sex inversion with 17a-methyltestosterone (Lee  et al., 1995). It was found that 5b-androstane-3b, 17b-diol and 5b-dihydrotestosterone are the only metabolites in the female phase. Although the production of these 5b-reduced androgens persisted in the male phase, there is a shift toward the production of 11b-hydroxytestosterone and 11-ketotestosterone as major metabolites. It was also found that the sperms from the induced males possess the enzyme, 20a-hydroxysteroid dehydrogenase (20a-HSD) and their single major metabolite 17, 20a-P (17a, 20a-dihydroxy-4-pregnen-3-one) may play a role in grouper reproduction (Tan  et al., 1995).

Several new products were also obtained from the extraction and purification work on grouper pituitaries by the NUS. They were purified grouper growth hormone, prolactin and GtHa and GtHIIb gonadotropin subunits. The cloning of these hormones was also performed and achieved.

Studies on Application of Thyroid Hormone and Cortisol

The other significant outcome from the project is the development of hatchery techniques of thyroid hormone treatment. It was first found that the thyroid hormone levels are higher in buoyant than in non-buoyant estuarine grouper eggs (Lam  et al., 1994). However, the evidence only points to a relationship between the buoyancy and viability of the grouper eggs and levels of thyroid hormone. It is not clear whether the thyroid hormones are the cause or the effect of egg buoyancy and viability (Lam  et al., 1994). However, the developmental effects of thyroid hormones on fish larvae have been extensively documented (Lam, 1994). Therefore, it is of interest that the effect of the thyroid hormone in grouper larvae and treatment protocols were then studied for hatchery application. The treatment protocols developed include immersion of fertilised eggs and oral route via bioencapsulation in Artemia nauplii to fish larvae (Tay  et al., 1994). The immersion of thyroid hormone solution of fertilised eggs (at 0.5 ppm triiodothyronine, T3 for 12 hours' post-fertilisation) improved larval survival and hatching rate. The acceleration of metamorphosis by bioencapsulation through Artemia nauplii (immersion dosage 0.5 ppm T3 for 6 hours) was also significant (98% vs 2% metamorphosis rate at Day 35). The synergistic effect of T3 and cortisol to grouper larvae were also studied (Tay  et al., 1997). Clearly, T3 promoted embryonic development while the role of cortisol remains unclear; both hormones promoted larval survival and synergism was evident.


Although farming technology of grouper in net-cages have been well developed and established the development of grouper breeding technology still continues in Singapore, as well as elsewhere in the region. In the context of Singapore’s emphasis on high technology farming, it is still important to establish breeding technology for this difficult marine food fish. The results from the grouper breeding programme with the National University of Singapore have been encouraging in that there is the possibility of using mass cloned hormones to improve spawning performance; the grouper male hormones identified as responsible for sex inversion and spermiation could be mass-produced for field application; and the refined larviculture techniques using thyroid hormone and cortisol could be incorporated into future hatchery protocols.



The authors wish to thank Mr Leslie Cheong, Professor Lam Toong Jin, and Associate Professor Tan Cheong Huat for reviewing the manuscript and Mr Hassanai Kongkeo, Coordinator of the Network of Aquaculture Centres in Asia-Pacific (NACA) for the invitation to present this paper.




Anon. 1986. Manual on floating netcage fish farming in Singapore’s coastal water, 1986. Fisheries Handbook No. 1. Primary Production Department, Republic of Singapore. 17 pp.

Chao, T. M. and M. Chow.  1990. Effect of methyltestosterone on gonadal development of Epinephelus tauvina (Forsskål). Singapore J. Pri. Ind. 18:1-14.

Chao, T. M., H. S. Lim and R. Chou. 1994. The first record of natural spawning in netcage and successful larviculture of four finger threadfin, Eleutheronema tetradactylum (Shaw) in Singapore. Singapore J. Pri. Ind. 22: 63-79.

Chao, T. M. and L. C. Lim. 1991. Recent development in the breeding of grouper (Epinephelus spp.) in Singapore. Singapore J. Pri. Ind. 19: 78-93.

Chao, T. M., L. C. Lim and L. T. Khoo. 1993. Studies on the breeding of brown-marbled grouper (Epinephelus fuscoguttatus, Forsskål) in Singapore, pp 143-156. In: Su, M. S., I. C. Liao and C. S. Lee (eds.). TML Conference Proceeding 3. Finfish Hatchery in Asia 1991, Tunkung Marine Laboratory, Taiwan Fisheries Research Institute, Taiwan.

Chen, F. Y. 1979. Progress and problem of net-cage culture of grouper (Epinephelus tauvina Forsskål) in Singapore. Proc. World Maricult. Soc. 10: 260-271.

Chen, F. Y. M. Chow, T. M. Chao and R. Lim. 1977. Artificial spawning and larval rearing of the grouper, Epinephelus tauvina (Forsskål) in Singapore. Singapore J. Pri. Ind . 5:1-21.

Chew-Lim, M, G. H. Ngoh, S. Y. Chong, H. C. F. Chua, Y. C. Chan, L. C. J. Howe, and E. W. Lim. 1992. Description of a virus isolated from the grouper Plectropomus maculatus.  J. Aqua. Animal Health 4: 222-226

Chong, Y. C. and T. M. Chao. 1986. Common Diseases of Marine Food fish.  Fisheries Handbook No. 2, Primary Production Department. 34 pp.

Chou, R.  1995. Aquafeeds and feeding strategies in Singapore, pp. 354-363. In: New, M. B., A. J. G. Tacon and I. Csavas (eds.) Farm-made Aquafeeds. FAO Fisheries Tech. Paper 343, 1995. 434 pp.  FAO, Rome, Italy.

Chou, R and H. B. Lee. in press. Commercial marine fish farming in Singapore. Presented in IFS/EC DGXII workshop on Aquaculture research and sustainable development in inland and coastal regions in South East Asia in Vietnam 18-22 March 1996.

Chua, F,  J. J. Loo,  J. Y. Wee and M. Ng. 1993. Findings from a fish disease survey: An overview of the marine fish disease situation in Singapore. Singapore J. Pri. Ind. 21(1): 26-37.

Chua, F. H. C., M. L. Ng, K. L. Ng, J. J. Loo, and J. Y. Wee. 1994. Investigation of outbreaks of a novel disease, ‘Sleepy Grouper Disease’, affecting the brown-spotted grouper, Epinephelus tauvina Forsskål. J. Fish Disease 17: 417-427.

Dhert, P., L. C. Lim, P. Lavens, T. M. Chao, R. Chou and P. Sorgeloos. 1991. Effect of dietary essential fatty acids on egg quality and larviculture success of the greasy grouper (Epinephelus tauvina, Forsskål) Preliminary results, pp 58-62. In: Lavens, P., P. Sorgeloos, E. Jaspers and F. Ollevier (eds). Larvi ‘91 Fish & Crustacean Larviculture Symposium. Short Communications and Abstracts. Special Publication No. 15. European Aquaculture Society, Ghent, Belgium.

Khin, P. K., R. Chou, and L. Cheong. 1987. Sanitization studies on imported marine food fish fingerlings. Singapore J. Pri. Ind. 15(2): 73-90.

Lam, T. J. 1994. Hormones and egg/larval quality in fish. J. World Aqua. Soc. 25: 2-12.

Lam, T. J., T. M. Chao, L. C. Lim, D. Nugegoda and A. N. Yong. 1994. Thyroid hormone levels are higher in buoyant then in non-buoyant eggs in greasy grouper, Epinephelus tauvina. Singapore J.  Pri.  Ind. 22(1): 29-33.

Lee, S. T. L., D. E. Kime, T. M. Chao, H. S. Lim, R. Chou, T. J. Lam and C. H. Tan. 1995. In vitro metabolism of testosterone by gonads of the grouper (Epinephelus tauvina) before and after sex inversion with 17a-methyltestosterone. Gen. Comp. Endocrinol. 99:41-49.

Lim, H. S. and T. M. Chao. 1993. The spontaneous spawning of mangrove red snapper, Lutjanus argentimaculatus (Forsskål), in net-cages. Singapore J. Pri. Ind. 21: 86-91.

Lim, L. C., L. Cheong, H. B. Lee, and H. H. Heng. 1985. Induced breeding studies of the John’s snapper. Singapore J. Pri. Ind. 13:70-83.

Lim, L. C., H. H. Heng, and H. B. Lee. 1986. The induced breeding of seabass, Lates calcarifer (Bloch) in Singapore. Singapore J. Pri. Ind. 14: 81-95.

Lim, L. C. 1993. Larviculture of the greasy grouper Epinephelus tauvina F. and the brown-marbled grouper, E. fuscoguttatus F., in Singapore. J. World Aqua. Soc. 24(2): 262-274.

Lim, L. C., T. M. Chao, and L.T. Khoo. 1990. Observations on the breeding of brown-marbled grouper, Epinephelus fuscoguttatus (Forskål). Singapore J. Pri. Ind. 18: 66-84.

Tan, A. M. C., S. T. L. Lee, D. F. Kime, T. M. Chao, H. S. Lim, R. Chou, T. J. Lam and H.C. Tan. 1995. 17a, 20a-dihydroxy-4-pregnen-3-one, not its 20b isomer, is produced from 17a-hydroxyprogesterone by permatozoa of secondary male groupers (Epinephelus tauvina) derived from females implanted with 17a-methyltestosterone. J. Exp. Zool. 271:462-465.

Tan, S. M. and K. S. Tan. 1974. Biology of tropical grouper Epinephelus tauvina (Forsskål) I. A preliminary study on hermaphroditism in E. tauvina. Singapore J. Pri. Ind. 2 (2): 123 -133.

Tay, H. C., J. Goh, A. N. Yong, T.M. Chao, H. S. Lim, R. Chou and T. J. Lam. 1994. Effect of thyroid hormone on metamorphosis in greasy grouper, Epinephelus tauvina. Singapore J. Pri. Ind. 22 (1): 35-38.

Tay, H. C., A. N. Yong, T. M. Chao, J. Goh, H. S. Lim, R. Chou and T. J. Lam. 1997. Effects of treatment of eggs with triiodothyronine and cortisol on the morphometry of newly hatched larvae and larval survival in the greasy grouper (Epinephelus coiodes).  Aqua. Int. 5:189-195.

Annex 1



(with special reference to grouper production in relation to total production) (in weight, W: metric tonnes, and in value, V: million S$)





















































































































































































Source: PPD’s submission for FAO Aquaculture Production Statistics


Annex  2





[1] Mariculture and Food fish Section, Primary Production Department, 300 Nicoll Drive, Changi Point, Singapore 498989