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A review of the culture of tropical abalone with special reference to Thailand
Aquaculture ELSEVIER
Aquaculture
140 (1996) 159-168
A review of the culture of tropical abalone with special reference to Thailand Padermsak Jarayabhand
aYbT *, Nittharatana
Paphavasit
b
aAquatic Resources Research Institute, Chulalongkorn University, Bangkok 10330. Thailand b Department of Marine Science, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand
Abstract Most species of abalone cultured throughout the world are either temperate or sub-tropical, and are relatively large compared with tropical species. However, markets for small or ‘cocktail size’ abalone are growing rapidly. Three species of tropical abalone are found in Thai waters: Huliotis minim, H. ouina and H. curia. At present, there is no commercial abalone culture in Thailand. This paper reviews the current research into the culture of tropical Thai abalone and both the advantages and disadvantages for cultivation. Although more research is needed, preliminary investigations indicate that the high growth rates and ease of spawning of Thai abalone offer excellent potential for cultivation. Keywords: Abalone;
Culture; Thailand;
Tropical
1. Introduction Abalone are ‘an economically important marine gastropod commanding moderate to high prices. Between 75 and 100 species have been identified worldwide, where large species generally populate temperate regions and small species populate tropical regions (Hahn, 1989; Uki, 1989). More than 20 species are classified as commercially important (Table l), most of which are relatively large species (except H. diuersicolor supertextu) harvested from natural stocks. Abalone are mainly produced in Japan, Australia, New Zealand, the United States, Mexico and South Africa (Uki, 1989). Owing to a rapid depletion of some stocks, many studies have been conducted in Japan and the United States to develop effective artificial propagation and culture techniques (Mottet, 1978). These studies were mainly focused on temperate species and had different degrees of
* Corresponding
author.
0044-8486/96/$15.00 0 1996 Elsevier Science B.V. All rights reserved SSDI 0044-8486(95)01194-3
160
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140 (1996) 159-168
Table 1 Commercialy important abalone species Scientific name
Common name
SL (mm)
H. rufescens H. jidgens H. corrugata H.sorenseni H. assimilis H. cracherodii H. walallensis H. kamtschntkana H. discus hannai H. discus H. diversicolor supertetia H. gigantea H. sieboldii H. asinina ’ H. rubra H. Iaevigata H. roei H. iris H. australis H. virginea H. tuberculata H. midae
Red Green, southern green or blue Pink or corrugated White or sorensen Threaded Black Flat or northern green Pinto Ezo awabi Kuro awabi, oni or onigai Tokobushi Madaka Megae Mimigai, donkey’s ear Black lip Green lip Roe’s Paua or black Silver or queen paua Virgin Onner Perlemon
> 275 125-200 150-175 125-200
’
Summarized from Hahn (1989) and Fallu (1991). SL, shell lengUxa Tropical species.
success. However, a rapid improvement in culture techniques in recent years has had a significant impact on abalone production, especially in Japan and Taiwan (Chen, 1989). Although large abalone are very popular in many Asian countries, small or ‘cocktail size’ abalone of 40-70 mm shell length (SL) are also popular in some countries. For example, Chen (1984) and Chen (1989) state that in Taiwan small abalone are preferred to large species owing to their delicate favour, appropriate size for banquets and price. The reader is referred to Chen (1989) for a comprehensive account of the culture of the small Taiwanese abalone, H. diuersicolor supertexta.
2. Abalone in Thailand and its potential cultivation Tantanasiriwong (1978) reported four tropical species of abalone in Thai waters, but this was later amended to three: H. asininu, H. ouina and H. zm-iu (Nateewathana and Hylleberg, 1986; Nateewathana and Bussarawit, 1988; Singhagraiwan and Doi, 1993; Jarayabhand et al., 1995). Historically, most abalone (recently identified as H. mind were caught by local fishermen and sold to restaurants in Bangkok. Until recently the statistics for total catches were not available, but there is a possibility that natural stocks will decline in the near future due to overfishing and habitat destruction. Based on their size and meat textures, there is potential to culture all three species of Thai abalone for
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140 (1996) 159-168
161
the cocktail-size market, as is happening with H. diuer.sicolor superfexru in Taiwan. Development of appropriate techniques for the commercial production of abalone in Thailand will have a significant effect, both in Thailand and surrounding regions. As only limited information on tropical abalone is available in Thailand, basic and applied research began in 1986 for H. minim and in 1989 for H. ouinu to establish abalone culture. So far, there is no research into the culture of the smallest species, H. uaria. 3. Biology and ecology 3.1. Morphology, behuviour, habitat, distribution and abundance
Table 2 outlines the morphological characteristics, habitat, distribution and abundance of the three Thai species. H. minim is clearly different from the other two abalone species from Thailand as it is larger and has a very thin, elongated shell and extended foot. Singhagraiwan and Doi (1993) reported that cultured H. usininu has a percentage ratio of meat weight to total weight of 85% compared with a ratio of 40% and 30% for wild H. ovinu and H. uuriu, respectively. Tanawansombat (1992) reported a similar Table 2 Morphological
characteristics,
habitat, distribution
and abundance
of abalone in Thailand
Description
H. asinina
H. ovina
H. varia
Morphology Shell Shape Colour Sculpture Thickness Tremata Foot Colour
Elongate Greenish brown Spiral Thin 6-7, smooth
Oval Olive green Prominent spiral Thick 4-6, highly elevated
Oval Dark brown spiral Moderate 3-5, slightly elevated
Grey
Cream to orange
Cream to orange
Regression coefficient Length and weight Length and width
3.225 0.527
3.034 0.716
2.705 0.687
Maximum size Shell length (mm) Total weight(g)
100 250-280
80 75
60 25
Habitat Zone Substrate Depth (m)
Inter- to subtidal Rock, dead coral l-7
Subtidal Rock crevice l-7
Inter- to subtidal Rock crevice l-7
Distribution Gulf of Thailand Andaman Sea
Chon Buri, Rayong Trad Puket
Chon Buri, Rayong Trad Ranong to Sand
No occurrence Ranong to Sand
Abundance Gulf of Thailand Andaman Sea
Rare Rare
Dominant Moderate
No record Dominant
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ratio for H. ouinu (51%). She also observed that the foot colour was orange in significantly more females than males. Thai abalone show a very clear nocturnal behaviour in both the field and the hatchery. During the day they shelter under rocks, or in crevices, dead coral heads or provided shelters; they emerge in the evening and hide again at dawn. Ngow and Jarayabhand (1993) reported that H. ovina prefer depths of between 1.5 m and 4 m, select rock crevices rather than coral substrate, and their preferred substrate size is larger than 0.1 m2. They are found with sea urchins, top shells, cowries, sea cucumbers, chitons and feather stars. It is interesting to note that the habitat where H. ovina occurs is devoid of algal beds or algal drift. Kamura (1989) reported that the production of benthic algae at Khang Kao Island, where H. ovina occurs, was between 3.53 and 7.15 g wet weight per 0.25 m* during a 3-week period. Of these algae, 11 were green, 2 brown, 13 red and 3 blue-green species. It is very likely that abalone have to compete intensively for food with other grazers in the same habitat. This requires further investigation. H. asininu, H. ouinu are found on the islands along the eastern coasts of the upper Gulf of Thailand, and all three species occur in the Andaman Sea ( Tookwinas et al., 1986; Nateewathana and Bussarawit, 1988; Jarayabhand et al., 1991; Kakhai and Petjamrat, 1992; Ngow and Jarayabhand, 1993). H. ovinu has been reported to be more common than H. usininu along the upper eastern Gulf of Thailand (Kakhai and Petjamrat, 1992), although Sungthong et al. (1991) found H. minim to be more common off Samet Island, Rayong Province. There is no report of H. vuriu in this area. Only small numbers of H. ovinu have been found along the lower eastern coast. In contrast, on the Andaman coastline the relative abundance of each species was 81% H. vuriu, 17.3% H. ovinu and 1.7% H. usininu. 3.2. Reproductive
biology
Like other Haliotids, Thai abalone are dioecious with external fertilization. There is no evidence of hermaphrodites. During the spawning season, males can easily be distinguished from females by the colour of the reproductive tissue covering the surface of the conical appendage (Table 3). Various investigations into the reproductive biology of Thai abalone have shown that all three species spawn almost continuously throughout the year and their sex ratios are
Table 3 Spawning
season, fecundity
aad gonad color of H. asinina, H. ovina and H. varia
Description
H. asinina
H. ovina
H. varia
Spawning Fecundity
Year round 2-6X 10’ ’
Year round 2.2-3.5 X 10’ b
Year round na
Gonad colour Male Female
Milky white Dark green
CtEam Dark green
Cream Dark green
a Singhagraiwan
and Doi (1992).b Kesthong
and Jarayabhand
(1993).na,
data not available.
P. Jarayabhand, N. Papbmasit/Aquaculture Table 4 Time reouired for embrvonic Developmental
and larval develonment
163
of H. asinim and H. ouim
Time required
stage
Unfertilized egg First polar body Second polar body First cleavage Second cleavage Third-sixth cleavage Rotating trochophom Hatch out Early vehger Late vehger Early creeping larvae Creeping larvae Juvenile ( 1-3 respiratory
pores)
a Singhagraiwan and Sasaki (1991).b Jarayabhand plates.na, data not available.
not significantly hand, 1993).
140 (1996) 159-168
different
H. asinina a
H. ovina b
0 na na 15-25 min 34-40 min 43-75 min 4.5 h Sh 8-9 h 22h 26hC 2-3 days 28 days
0 10 min 1.5 min 20 min 40 min 2-4 h 5-6 h 7-8 h lo-12 18-22 na 36-40 20-24
et al. (1992J.C Introduction
from 1: 1 (Jarayabhand
h h h ’ days
of pre-prepared
et al., 1992; Kesthong
diatom culture
and Jarayab-
3.3. Embryonic and larval development The embryonic and larval development of H. usininu and H. ovina were reported by Singhagraiwan and Sasaki (1991) and Jarayabhand et al. (1992), respectively. The average egg diameter of H. usininu is 190 km and for H. ovinu it is 180 Frn. These diameters are clearly smaller than those of temperate abalone species (Jarayabhand et al., 1995), but within the same range as H. diuersicolor supertextu (Chen, 1989). The rates of successive embryonic and larval stages of H. usininu and H. ovinu are very similar within the same temperature range (Table 4) and similar to those reported for other species of abalone (Hahn, 1989).
4. Culture techniques Although culture techniques are well described for many abalone species, information on the culture of tropical abalone comes largely from the studies done on H. diuersicolor supertextu. In Thailand, culture techniques for H. usininu and H. ouinu have been investigated with different degrees of success. In general, the main culture procedure used is similar to those used for other abalone species, with slight differences in detail. 4.1. Broodstock conditioning H. usinina broodstock can be conditioned and spawned in the hatchery using flow-through seawater (500 1 h-’ ) and fed sufficient amounts of the red alga Gruciluriu
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salicorniu (Singhagraiwan and Doi, 1992). Broodstock (5-9 cm SL) were maintained in 2.5 ton concrete tanks at a sex ratio of 1 male to 5 females and a stocking density of 60-120 individuals per tank. Spawning occurred almost continuously throughout the year, with a peak from September to March. Broodstock collected from nature performed better than those produced in the hatchery. Conditioning of H. ouina has also been investigated by Jarayabhand et al. (1991) with promising results. The degree of gonad maturation of H. ouina is a function of the effective accumulation temperature. It is possible to produce mature H. ouina broodstock throughout the year. Thus, the key factors for broodstock conditioning of tropical abalone are good rearing conditions and nutrition. The ability to obtain fully mature abalone throughout the year is a key advantage of tropical abalone culture. 4.2. Induction of spawning The control of spawning is a vital step for successful seed production as the artificial induction of spawning allows the production of larvae over a longer period than natural, spontaneous spawning. However, this may not be so crucial for tropical abalone which can spawn throughout the year. Singhagraiwan and Doi (1993) reported that spontaneous spawning of H. usininu is very simple and used routinely in their hatchery. Several methods of inducing spawning of H. ouinu, such as natural spawning, desiccation, thermal shock, hydrogen peroxide and UV irradiation, have been tried (Jarayabhand et al., 1995). The UV-irradiated seawater method is used as a routine procedure in our experimental hatchery with acceptable results. This method allows a better control of fertilization and avoids problems originating from sperm competition that can occur when using the spontaneous spawning method. Moreover, this method is essential when selective breeding, hybridization and chromosome manipulation are integrated into abalone culture. So far there are no reports on the optimal sperm density for these two species. 4.3. Embryonic, larval and spat rearing Fertilized eggs are kept in either broodstock tanks (H. usininu) or incubation tanks (H. ouinu). In the case of H. usininu, healthy trochophore larvae swim up to the surface where they are siphoned off and transferred to 30 1 larval rearing tanks (Singhagraiwan and Doi, 1993). Filtered seawater (1 km) gently flows from the top of the tank and out through a nitex screen (60 pm). Using this system, waste from dead embryos and larvae are discharged from the bottom (Singhagraiwan and Doi, 1993). At this stage stocking density is 10 larvae cm-’ and the survival is 90%., Larvae with creeping ability are transferred into larval settling tanks installed with bundles of pre-prepared culture plates. These plates are covered with thin films of benthic diatoms, such as Nitz&iu spp. and Nuuiculu spp. At present, the settling rate is about 10%. The procedure for H. ouinu is almost the same except that the larval rearing tank and larval settling tank are the same (Jarayabhand et al., 1995).
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N. Paphavasit/Aquaculture
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4.4. Weaning
When juvenile abalone change their life mode from a pelagic into a benthic form they start feeding on benthic diatoms, and continue on this diet until l-2 cm SL (3-5 months old). Care must be taken to ensure sufficient growth of benthic diatoms by controlling light density and ensuring the correct supply of fertilizer into the rearing tanks. The survival rate of juvenile H. usininu during the period from first settlement to about 2 cm SL is about 20%. It is recognized that growth variation up to this stage is very high in both species. Juveniles between 1 and 2 cm SL start to feed on macroalgae. 4.5. Grow-out Juveniles of l-2 cm SL can actively feed on macroalgae or artificial diets until they reach market size. This step is known as the grow-out phase. The red alga G. sulicorniu produced the best growth and survival rates in H. usininu (Singhagraiwan and Doi, 1993), while the green alga Enteromorphu intestinalis also produced acceptable results for both H. usininu and H. ouinu (unpublished data). Grucilariu was also recognized as the best food during the grow-out phase for H. diuersicofor supertextu (Chen, 1984; Chen, 1989). Due to difficulties in supplying G. sulicorniu during some seasons, experiments on using artificial diets are being investigated for both species with very promising results (Jarayabhand et al., 1995). A market size of 4 cm SL or more was obtained for H. usininu within a year (Singhagraiwan and Doi, 1993). It is clear that the growth rates of H. usininu and H. ouinu are similar to those of the Taiwanese species H. diuersicolor supertextu (Chen, 1989), all of which are considerably higher than those of temperate species. This is an important advantage for tropical abalone culture. Two types of grow-out systems are used for the tropical abalone H. diuersicolor supertextu; intertidal ponds and onshore ponds (Chen, 1989). The intertidal ponds are superior both in terms of abalone growth performance and economics. However, intertidal ponds may not be acceptable to the Thai government as intertidal areas belong to the public. Consequently, land-based systems or on-shore ponds may prove more feasible. At present there are no commercial grow-out systems for Thai abalone. Various experiments on factors affecting growth performance of Thai abalone have been conducted. Optimum stocking density for H. usininu was investigated by using 2.5 ton concrete tanks with a continuous supply of seawater (200-500 1 h-l). He suggested an initial stocking density for 2.5 cm SL abalone of 1462 individuals m-*. However, as the experiment lasted only 100 days, this figure cannot be used as a grow-out density. Chen (1989) suggested that a stocking density of between 200 and 400 individuals m-* was suitable for the grow-out of 1.5 cm SL animals. Generally, growth rates of abalone depend very much on rearing environments. These figures can be used only as a guide while further investigations are conducted. The growth and survival rates of H. usininu reared in closed and flow-through systems were compared by Singhagraiwan and Doi (1993). The closed system produced slower growth rates and higher mortality than the open system. A closed system using a biological filter is currently on trial in our hatchery.
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Effects of salinity on growth and survival rate were observed for H. asinina by Singhagraiwan et al. (1992). They concluded that juvenile H. asinina could survive and produce reasonable growth rates at salinities between 22.5 and 32.5 ppt. Growth rates were slightly retarded at the lower range, although short-term exposure to 22.5 ppt. is possible without detrimental effects. The growth rate of juvenile H. diuersicolor supertexta was also retarded as salinity decreased (Chen, 1989). He reported that juveniles die after 60 days in 25 ppt. and after 30 days in 20 ppt. Salinities between 32 and 35 ppt. were considered optimum for H. diversicolor supertexta held in grow-out ponds. Our experience with H. ovina suggest that they can also tolerate salinity as low as 20 ppt. for at least 1 week, but their feeding rates decrease considerably (unpublished data).
5. Conclusions Tropical abalone culture in Thailand is at the very early stages of basic and applied research conducted in small-scale operations. However, the results obtained so far are very promising. In addition to their relatively small size, tropical abalone have many advantages for culture over temperate abalone. These include the ability to produce mature animals throughout the year, successful maturation of stock produced in the hatchery, fast growth rates and a relatively high salinity tolerance. It is expected that Thai abalone will have a relatively short production time of l-2 years. In terms of commercial production and marketing, the successful culture of the small Taiwanese abalone H. diuersicolor supertexta can be used as an example. However, further investigations of the most appropriate commercial systems for seed production and grow-out in Thailand are needed. In addition, more research into the biology, ecology, nutrition (both algal and artificial diets), grow-out techniques, biotechnology (production of triploid abalone) and genetics (selections and hybridization) are necessary for the future of tropical abalone culture in Thailand and surrounding regions.
Acknowledgements We would like to thank the Toray Science International Research Grant 1990 for funding the project entitled ‘Research and Development on some Aspects of Abalone Culture (Haliotis ovina Gmelin, 1791)‘. We also thank the Hitachi Research Grant 1991-1993 for funding the project entitled ‘Development of Commercial Abalone Culture in Thailand’. We would also like to thank the staff of the Angsila Marine Biological Research Station and the Sichang Marine Science Research and Training Station, Chulalongkom University, for their help in many ways. Last, but not least, the undergraduate and graduate students from the Department of Marine Science and Department of Biotechnology for their help in specimen collection, laboratory and hatchery experiments. Dr. Ann Fleming critically reviewed and extensively edited the manuscript.
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References Chen, H.C., 1984. Recent innovation in cultivation of edible molluscs in Taiwan, with special reference to the small abalone Haliotis diversicofor supertexta and the hard clam Meretrix lusoria. Aquaculture, 39: 1l-27. Chen, H.C., 1989. Farming the small abalone Haliotis diversicolor supertextu in Taiwan. In: K.O. Hahn (Editor), Handbook of Culture of Abalone and Other Marine Gastropods. CRC Press, Boca Raton, FL, pp. 265-283. Fallu, R., 1991. Abalone Farming. Fishing News Books, Oxford, 19.5 pp. Hahn, K.O., 1989. Handbook of Culture of Abalone and other Marine Gastropcds. CRC Press, Boca Raton, FL, 348 PP. Jarayabhand, P., Piyateeratitivorakul, S., Choonhabandit, S. and Rungsupa, S., 1991. Final report on research and development on some aspects of abalone culture. Presented to the Toray Science International Research Grant 1990, Bangkok, 52 pp. Jarayabhand, P., Jew, N. and Choonbabandit, S., 1992. Gametogenic cycle of abalone, Hafiotis ovine (Gmelin, 17911, at Khangkao Island, Chon Buri Province. Presented at the 18th Congress on Science and Technology of Thailand, 27-29 October 1992, Bangkok, pp. 340-341 (in Thai, with English abstract). Jarayabhand, P., Kojima, H. and Menasveta, P., 1995. Embryonic and larval development, and early growth of hatchery-produced abalone (H&Otis ovine Gmelin, 1791) seed. Thai J. Aqua. Sci., l(2): 194-202. Kakhai, N. and Petjamrat, K., 1992. Survey on species and broodstock collection of abalone (Haliotis spp.) in Chon Buri, Rayong and Trad Provinces. Technical Paper No. 6/1992, Rayong Coastal Aquaculture Station, Department of Fisheries, Ministry of Agriculture and Cooperatives, Thailand, 3 1 pp. (in Thai, with English abstract). Kamura, S., 1989. Experimental studies on bentbic algal growth in a subtidal coral area in the Gulf of Thailand. Galaxea, 8: 217-229. Kesthong, W. and Jarayabhand, P., 1993. Study on fecundity in abalone, Haliotis ovina (Gmelin, 1791) along the eastern coast of Thailand. Presented at the 19th Congress on Science and Technology of Thailand, 27-29 October 1993, Bangkok, pp. 472-473 (in Thai, with English abstract). Mottet, M.G., 1978. A review of the fishery biology of abalones. Technical Report No. 37, March 1978, Department of Fisheries, Washington, DC. Nateewathana, A. and Bussarawit, S., 1988. Abundance and distribution of abalone along the Andaman Sea Coast of Thailand. Kasetsart J. (Sci.1, 22: 8- 15 (in Thai, with English abstract). Nateewathana, A. and Hylleberg, J., 1986. A survey on Thai abalone around Phuket Island and feasibility study of abalone culture in Thailand. Thai Fish. Gaz., 39: 177- 192 (in Thai, with English abstract). Ngow, 0. and Jarayabhand, P., 1993. Distribution and habitat selection of the abalone, Haliotis ovina (Gmelin, 17911, at the eastern coast of Thailand. Presented at the 19th Congress on Science and Technology of Thailand, 27-29 October 1993, Bangkok, pp. 472-473 (in Thai, with English abstract). Singhagraiwan, T. and Doi, M., 1992. Spawning pattern and fecundity of the Donkey’s ear abalone, observed in captivity. Thai. Mar. Fish. Res. Bull., 3: 61-69. Singhagraiwan, T. and Doi, M., 1993. Seed production and culture of a tropical abalone, Haliotis asinina Linne. The Research Project of Fishery Resources Development in the Kingdom of Thailand. The Eastern Marine Fisheries Development Center (EMFDC), Department of Fisheries, Ministry of Agriculture and Cooperatives, Thailand, 32 pp. Singhagraiwan, T. and Sasaki, M., 1991. Breeding and early development of the donkey’s ear abalone, Haliotis asinina Linne. Thai. Mar. Fish. Res. Bull., 2: 95-100. Singhagraiwan, T., Doi, M. and Sasaki, M., 1992. Salinity tolerance of juvenile Donkey’s ear abalone Haliotis asinine Linne. Thai. Mar. Fish. Res. Bull., 3: 71-77. Sungthong, S., Ingsrisawang, V. and Fujiwara, S., 199 1. Study on the relative growth of abalone, Haliotis nsinina Linne, off Samet Island. Thai. Mar. Fish. Res. Bull., 2: 15-20. Tanawansombat, S., 1992. A study on some basic biological aspects of the abalone, Haliotis ovina (Gmelin, 1791) at the eastern coast of Thailand. Special problems. Department of Marine Science, Chulalongkom University, 62 pp. (in Thai, with English abstract). Tantanasiriwong, R., 1978. An illustrated checklist of marine gastropods from Phuket Island, adjacent
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mainland and offshore island, Western Peninsular, Tbailand. Res. Bull. No. 21, Phuket Marine Biological Center, 22 pp. Tookwinas, S., Leknim, W., Donyadol, Y., Pre.edalampabuttra, Y. and Pemgmak, P., 1986. Survey on species and distribution of abalone (Haliotis spp.) in Sumttani, Nakomsrithammarat and Songkhla Provinces. Contribution No. l/1986, National Institute of Coastal Aquaculture, Department of Fisheries, Thailand, 16 pp. (in Thai, with English abstract). Uki, N., 1989. Abalone seedling production and its theory. 1. Int. J. Agric. Fish. Technol., 1: 3-15.
Aquaculture
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A review of the culture of tropical abalone with special reference to Thailand Padermsak Jarayabhand
aYbT *, Nittharatana
Paphavasit
b
aAquatic Resources Research Institute, Chulalongkorn University, Bangkok 10330. Thailand b Department of Marine Science, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand
Abstract Most species of abalone cultured throughout the world are either temperate or sub-tropical, and are relatively large compared with tropical species. However, markets for small or ‘cocktail size’ abalone are growing rapidly. Three species of tropical abalone are found in Thai waters: Huliotis minim, H. ouina and H. curia. At present, there is no commercial abalone culture in Thailand. This paper reviews the current research into the culture of tropical Thai abalone and both the advantages and disadvantages for cultivation. Although more research is needed, preliminary investigations indicate that the high growth rates and ease of spawning of Thai abalone offer excellent potential for cultivation. Keywords: Abalone;
Culture; Thailand;
Tropical
1. Introduction Abalone are ‘an economically important marine gastropod commanding moderate to high prices. Between 75 and 100 species have been identified worldwide, where large species generally populate temperate regions and small species populate tropical regions (Hahn, 1989; Uki, 1989). More than 20 species are classified as commercially important (Table l), most of which are relatively large species (except H. diuersicolor supertextu) harvested from natural stocks. Abalone are mainly produced in Japan, Australia, New Zealand, the United States, Mexico and South Africa (Uki, 1989). Owing to a rapid depletion of some stocks, many studies have been conducted in Japan and the United States to develop effective artificial propagation and culture techniques (Mottet, 1978). These studies were mainly focused on temperate species and had different degrees of
* Corresponding
author.
0044-8486/96/$15.00 0 1996 Elsevier Science B.V. All rights reserved SSDI 0044-8486(95)01194-3
160
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Table 1 Commercialy important abalone species Scientific name
Common name
SL (mm)
H. rufescens H. jidgens H. corrugata H.sorenseni H. assimilis H. cracherodii H. walallensis H. kamtschntkana H. discus hannai H. discus H. diversicolor supertetia H. gigantea H. sieboldii H. asinina ’ H. rubra H. Iaevigata H. roei H. iris H. australis H. virginea H. tuberculata H. midae
Red Green, southern green or blue Pink or corrugated White or sorensen Threaded Black Flat or northern green Pinto Ezo awabi Kuro awabi, oni or onigai Tokobushi Madaka Megae Mimigai, donkey’s ear Black lip Green lip Roe’s Paua or black Silver or queen paua Virgin Onner Perlemon
> 275 125-200 150-175 125-200
’
Summarized from Hahn (1989) and Fallu (1991). SL, shell lengUxa Tropical species.
success. However, a rapid improvement in culture techniques in recent years has had a significant impact on abalone production, especially in Japan and Taiwan (Chen, 1989). Although large abalone are very popular in many Asian countries, small or ‘cocktail size’ abalone of 40-70 mm shell length (SL) are also popular in some countries. For example, Chen (1984) and Chen (1989) state that in Taiwan small abalone are preferred to large species owing to their delicate favour, appropriate size for banquets and price. The reader is referred to Chen (1989) for a comprehensive account of the culture of the small Taiwanese abalone, H. diuersicolor supertexta.
2. Abalone in Thailand and its potential cultivation Tantanasiriwong (1978) reported four tropical species of abalone in Thai waters, but this was later amended to three: H. asininu, H. ouina and H. zm-iu (Nateewathana and Hylleberg, 1986; Nateewathana and Bussarawit, 1988; Singhagraiwan and Doi, 1993; Jarayabhand et al., 1995). Historically, most abalone (recently identified as H. mind were caught by local fishermen and sold to restaurants in Bangkok. Until recently the statistics for total catches were not available, but there is a possibility that natural stocks will decline in the near future due to overfishing and habitat destruction. Based on their size and meat textures, there is potential to culture all three species of Thai abalone for
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161
the cocktail-size market, as is happening with H. diuer.sicolor superfexru in Taiwan. Development of appropriate techniques for the commercial production of abalone in Thailand will have a significant effect, both in Thailand and surrounding regions. As only limited information on tropical abalone is available in Thailand, basic and applied research began in 1986 for H. minim and in 1989 for H. ouinu to establish abalone culture. So far, there is no research into the culture of the smallest species, H. uaria. 3. Biology and ecology 3.1. Morphology, behuviour, habitat, distribution and abundance
Table 2 outlines the morphological characteristics, habitat, distribution and abundance of the three Thai species. H. minim is clearly different from the other two abalone species from Thailand as it is larger and has a very thin, elongated shell and extended foot. Singhagraiwan and Doi (1993) reported that cultured H. usininu has a percentage ratio of meat weight to total weight of 85% compared with a ratio of 40% and 30% for wild H. ovinu and H. uuriu, respectively. Tanawansombat (1992) reported a similar Table 2 Morphological
characteristics,
habitat, distribution
and abundance
of abalone in Thailand
Description
H. asinina
H. ovina
H. varia
Morphology Shell Shape Colour Sculpture Thickness Tremata Foot Colour
Elongate Greenish brown Spiral Thin 6-7, smooth
Oval Olive green Prominent spiral Thick 4-6, highly elevated
Oval Dark brown spiral Moderate 3-5, slightly elevated
Grey
Cream to orange
Cream to orange
Regression coefficient Length and weight Length and width
3.225 0.527
3.034 0.716
2.705 0.687
Maximum size Shell length (mm) Total weight(g)
100 250-280
80 75
60 25
Habitat Zone Substrate Depth (m)
Inter- to subtidal Rock, dead coral l-7
Subtidal Rock crevice l-7
Inter- to subtidal Rock crevice l-7
Distribution Gulf of Thailand Andaman Sea
Chon Buri, Rayong Trad Puket
Chon Buri, Rayong Trad Ranong to Sand
No occurrence Ranong to Sand
Abundance Gulf of Thailand Andaman Sea
Rare Rare
Dominant Moderate
No record Dominant
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140 (1996) 159-168
ratio for H. ouinu (51%). She also observed that the foot colour was orange in significantly more females than males. Thai abalone show a very clear nocturnal behaviour in both the field and the hatchery. During the day they shelter under rocks, or in crevices, dead coral heads or provided shelters; they emerge in the evening and hide again at dawn. Ngow and Jarayabhand (1993) reported that H. ovina prefer depths of between 1.5 m and 4 m, select rock crevices rather than coral substrate, and their preferred substrate size is larger than 0.1 m2. They are found with sea urchins, top shells, cowries, sea cucumbers, chitons and feather stars. It is interesting to note that the habitat where H. ovina occurs is devoid of algal beds or algal drift. Kamura (1989) reported that the production of benthic algae at Khang Kao Island, where H. ovina occurs, was between 3.53 and 7.15 g wet weight per 0.25 m* during a 3-week period. Of these algae, 11 were green, 2 brown, 13 red and 3 blue-green species. It is very likely that abalone have to compete intensively for food with other grazers in the same habitat. This requires further investigation. H. asininu, H. ouinu are found on the islands along the eastern coasts of the upper Gulf of Thailand, and all three species occur in the Andaman Sea ( Tookwinas et al., 1986; Nateewathana and Bussarawit, 1988; Jarayabhand et al., 1991; Kakhai and Petjamrat, 1992; Ngow and Jarayabhand, 1993). H. ovinu has been reported to be more common than H. usininu along the upper eastern Gulf of Thailand (Kakhai and Petjamrat, 1992), although Sungthong et al. (1991) found H. minim to be more common off Samet Island, Rayong Province. There is no report of H. vuriu in this area. Only small numbers of H. ovinu have been found along the lower eastern coast. In contrast, on the Andaman coastline the relative abundance of each species was 81% H. vuriu, 17.3% H. ovinu and 1.7% H. usininu. 3.2. Reproductive
biology
Like other Haliotids, Thai abalone are dioecious with external fertilization. There is no evidence of hermaphrodites. During the spawning season, males can easily be distinguished from females by the colour of the reproductive tissue covering the surface of the conical appendage (Table 3). Various investigations into the reproductive biology of Thai abalone have shown that all three species spawn almost continuously throughout the year and their sex ratios are
Table 3 Spawning
season, fecundity
aad gonad color of H. asinina, H. ovina and H. varia
Description
H. asinina
H. ovina
H. varia
Spawning Fecundity
Year round 2-6X 10’ ’
Year round 2.2-3.5 X 10’ b
Year round na
Gonad colour Male Female
Milky white Dark green
CtEam Dark green
Cream Dark green
a Singhagraiwan
and Doi (1992).b Kesthong
and Jarayabhand
(1993).na,
data not available.
P. Jarayabhand, N. Papbmasit/Aquaculture Table 4 Time reouired for embrvonic Developmental
and larval develonment
163
of H. asinim and H. ouim
Time required
stage
Unfertilized egg First polar body Second polar body First cleavage Second cleavage Third-sixth cleavage Rotating trochophom Hatch out Early vehger Late vehger Early creeping larvae Creeping larvae Juvenile ( 1-3 respiratory
pores)
a Singhagraiwan and Sasaki (1991).b Jarayabhand plates.na, data not available.
not significantly hand, 1993).
140 (1996) 159-168
different
H. asinina a
H. ovina b
0 na na 15-25 min 34-40 min 43-75 min 4.5 h Sh 8-9 h 22h 26hC 2-3 days 28 days
0 10 min 1.5 min 20 min 40 min 2-4 h 5-6 h 7-8 h lo-12 18-22 na 36-40 20-24
et al. (1992J.C Introduction
from 1: 1 (Jarayabhand
h h h ’ days
of pre-prepared
et al., 1992; Kesthong
diatom culture
and Jarayab-
3.3. Embryonic and larval development The embryonic and larval development of H. usininu and H. ovina were reported by Singhagraiwan and Sasaki (1991) and Jarayabhand et al. (1992), respectively. The average egg diameter of H. usininu is 190 km and for H. ovinu it is 180 Frn. These diameters are clearly smaller than those of temperate abalone species (Jarayabhand et al., 1995), but within the same range as H. diuersicolor supertextu (Chen, 1989). The rates of successive embryonic and larval stages of H. usininu and H. ovinu are very similar within the same temperature range (Table 4) and similar to those reported for other species of abalone (Hahn, 1989).
4. Culture techniques Although culture techniques are well described for many abalone species, information on the culture of tropical abalone comes largely from the studies done on H. diuersicolor supertextu. In Thailand, culture techniques for H. usininu and H. ouinu have been investigated with different degrees of success. In general, the main culture procedure used is similar to those used for other abalone species, with slight differences in detail. 4.1. Broodstock conditioning H. usinina broodstock can be conditioned and spawned in the hatchery using flow-through seawater (500 1 h-’ ) and fed sufficient amounts of the red alga Gruciluriu
164
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salicorniu (Singhagraiwan and Doi, 1992). Broodstock (5-9 cm SL) were maintained in 2.5 ton concrete tanks at a sex ratio of 1 male to 5 females and a stocking density of 60-120 individuals per tank. Spawning occurred almost continuously throughout the year, with a peak from September to March. Broodstock collected from nature performed better than those produced in the hatchery. Conditioning of H. ouina has also been investigated by Jarayabhand et al. (1991) with promising results. The degree of gonad maturation of H. ouina is a function of the effective accumulation temperature. It is possible to produce mature H. ouina broodstock throughout the year. Thus, the key factors for broodstock conditioning of tropical abalone are good rearing conditions and nutrition. The ability to obtain fully mature abalone throughout the year is a key advantage of tropical abalone culture. 4.2. Induction of spawning The control of spawning is a vital step for successful seed production as the artificial induction of spawning allows the production of larvae over a longer period than natural, spontaneous spawning. However, this may not be so crucial for tropical abalone which can spawn throughout the year. Singhagraiwan and Doi (1993) reported that spontaneous spawning of H. usininu is very simple and used routinely in their hatchery. Several methods of inducing spawning of H. ouinu, such as natural spawning, desiccation, thermal shock, hydrogen peroxide and UV irradiation, have been tried (Jarayabhand et al., 1995). The UV-irradiated seawater method is used as a routine procedure in our experimental hatchery with acceptable results. This method allows a better control of fertilization and avoids problems originating from sperm competition that can occur when using the spontaneous spawning method. Moreover, this method is essential when selective breeding, hybridization and chromosome manipulation are integrated into abalone culture. So far there are no reports on the optimal sperm density for these two species. 4.3. Embryonic, larval and spat rearing Fertilized eggs are kept in either broodstock tanks (H. usininu) or incubation tanks (H. ouinu). In the case of H. usininu, healthy trochophore larvae swim up to the surface where they are siphoned off and transferred to 30 1 larval rearing tanks (Singhagraiwan and Doi, 1993). Filtered seawater (1 km) gently flows from the top of the tank and out through a nitex screen (60 pm). Using this system, waste from dead embryos and larvae are discharged from the bottom (Singhagraiwan and Doi, 1993). At this stage stocking density is 10 larvae cm-’ and the survival is 90%., Larvae with creeping ability are transferred into larval settling tanks installed with bundles of pre-prepared culture plates. These plates are covered with thin films of benthic diatoms, such as Nitz&iu spp. and Nuuiculu spp. At present, the settling rate is about 10%. The procedure for H. ouinu is almost the same except that the larval rearing tank and larval settling tank are the same (Jarayabhand et al., 1995).
P. Jarayabhmd,
N. Paphavasit/Aquaculture
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165
4.4. Weaning
When juvenile abalone change their life mode from a pelagic into a benthic form they start feeding on benthic diatoms, and continue on this diet until l-2 cm SL (3-5 months old). Care must be taken to ensure sufficient growth of benthic diatoms by controlling light density and ensuring the correct supply of fertilizer into the rearing tanks. The survival rate of juvenile H. usininu during the period from first settlement to about 2 cm SL is about 20%. It is recognized that growth variation up to this stage is very high in both species. Juveniles between 1 and 2 cm SL start to feed on macroalgae. 4.5. Grow-out Juveniles of l-2 cm SL can actively feed on macroalgae or artificial diets until they reach market size. This step is known as the grow-out phase. The red alga G. sulicorniu produced the best growth and survival rates in H. usininu (Singhagraiwan and Doi, 1993), while the green alga Enteromorphu intestinalis also produced acceptable results for both H. usininu and H. ouinu (unpublished data). Grucilariu was also recognized as the best food during the grow-out phase for H. diuersicofor supertextu (Chen, 1984; Chen, 1989). Due to difficulties in supplying G. sulicorniu during some seasons, experiments on using artificial diets are being investigated for both species with very promising results (Jarayabhand et al., 1995). A market size of 4 cm SL or more was obtained for H. usininu within a year (Singhagraiwan and Doi, 1993). It is clear that the growth rates of H. usininu and H. ouinu are similar to those of the Taiwanese species H. diuersicolor supertextu (Chen, 1989), all of which are considerably higher than those of temperate species. This is an important advantage for tropical abalone culture. Two types of grow-out systems are used for the tropical abalone H. diuersicolor supertextu; intertidal ponds and onshore ponds (Chen, 1989). The intertidal ponds are superior both in terms of abalone growth performance and economics. However, intertidal ponds may not be acceptable to the Thai government as intertidal areas belong to the public. Consequently, land-based systems or on-shore ponds may prove more feasible. At present there are no commercial grow-out systems for Thai abalone. Various experiments on factors affecting growth performance of Thai abalone have been conducted. Optimum stocking density for H. usininu was investigated by using 2.5 ton concrete tanks with a continuous supply of seawater (200-500 1 h-l). He suggested an initial stocking density for 2.5 cm SL abalone of 1462 individuals m-*. However, as the experiment lasted only 100 days, this figure cannot be used as a grow-out density. Chen (1989) suggested that a stocking density of between 200 and 400 individuals m-* was suitable for the grow-out of 1.5 cm SL animals. Generally, growth rates of abalone depend very much on rearing environments. These figures can be used only as a guide while further investigations are conducted. The growth and survival rates of H. usininu reared in closed and flow-through systems were compared by Singhagraiwan and Doi (1993). The closed system produced slower growth rates and higher mortality than the open system. A closed system using a biological filter is currently on trial in our hatchery.
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Effects of salinity on growth and survival rate were observed for H. asinina by Singhagraiwan et al. (1992). They concluded that juvenile H. asinina could survive and produce reasonable growth rates at salinities between 22.5 and 32.5 ppt. Growth rates were slightly retarded at the lower range, although short-term exposure to 22.5 ppt. is possible without detrimental effects. The growth rate of juvenile H. diuersicolor supertexta was also retarded as salinity decreased (Chen, 1989). He reported that juveniles die after 60 days in 25 ppt. and after 30 days in 20 ppt. Salinities between 32 and 35 ppt. were considered optimum for H. diversicolor supertexta held in grow-out ponds. Our experience with H. ovina suggest that they can also tolerate salinity as low as 20 ppt. for at least 1 week, but their feeding rates decrease considerably (unpublished data).
5. Conclusions Tropical abalone culture in Thailand is at the very early stages of basic and applied research conducted in small-scale operations. However, the results obtained so far are very promising. In addition to their relatively small size, tropical abalone have many advantages for culture over temperate abalone. These include the ability to produce mature animals throughout the year, successful maturation of stock produced in the hatchery, fast growth rates and a relatively high salinity tolerance. It is expected that Thai abalone will have a relatively short production time of l-2 years. In terms of commercial production and marketing, the successful culture of the small Taiwanese abalone H. diuersicolor supertexta can be used as an example. However, further investigations of the most appropriate commercial systems for seed production and grow-out in Thailand are needed. In addition, more research into the biology, ecology, nutrition (both algal and artificial diets), grow-out techniques, biotechnology (production of triploid abalone) and genetics (selections and hybridization) are necessary for the future of tropical abalone culture in Thailand and surrounding regions.
Acknowledgements We would like to thank the Toray Science International Research Grant 1990 for funding the project entitled ‘Research and Development on some Aspects of Abalone Culture (Haliotis ovina Gmelin, 1791)‘. We also thank the Hitachi Research Grant 1991-1993 for funding the project entitled ‘Development of Commercial Abalone Culture in Thailand’. We would also like to thank the staff of the Angsila Marine Biological Research Station and the Sichang Marine Science Research and Training Station, Chulalongkom University, for their help in many ways. Last, but not least, the undergraduate and graduate students from the Department of Marine Science and Department of Biotechnology for their help in specimen collection, laboratory and hatchery experiments. Dr. Ann Fleming critically reviewed and extensively edited the manuscript.
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References Chen, H.C., 1984. Recent innovation in cultivation of edible molluscs in Taiwan, with special reference to the small abalone Haliotis diversicofor supertexta and the hard clam Meretrix lusoria. Aquaculture, 39: 1l-27. Chen, H.C., 1989. Farming the small abalone Haliotis diversicolor supertextu in Taiwan. In: K.O. Hahn (Editor), Handbook of Culture of Abalone and Other Marine Gastropods. CRC Press, Boca Raton, FL, pp. 265-283. Fallu, R., 1991. Abalone Farming. Fishing News Books, Oxford, 19.5 pp. Hahn, K.O., 1989. Handbook of Culture of Abalone and other Marine Gastropcds. CRC Press, Boca Raton, FL, 348 PP. Jarayabhand, P., Piyateeratitivorakul, S., Choonhabandit, S. and Rungsupa, S., 1991. Final report on research and development on some aspects of abalone culture. Presented to the Toray Science International Research Grant 1990, Bangkok, 52 pp. Jarayabhand, P., Jew, N. and Choonbabandit, S., 1992. Gametogenic cycle of abalone, Hafiotis ovine (Gmelin, 17911, at Khangkao Island, Chon Buri Province. Presented at the 18th Congress on Science and Technology of Thailand, 27-29 October 1992, Bangkok, pp. 340-341 (in Thai, with English abstract). Jarayabhand, P., Kojima, H. and Menasveta, P., 1995. Embryonic and larval development, and early growth of hatchery-produced abalone (H&Otis ovine Gmelin, 1791) seed. Thai J. Aqua. Sci., l(2): 194-202. Kakhai, N. and Petjamrat, K., 1992. Survey on species and broodstock collection of abalone (Haliotis spp.) in Chon Buri, Rayong and Trad Provinces. Technical Paper No. 6/1992, Rayong Coastal Aquaculture Station, Department of Fisheries, Ministry of Agriculture and Cooperatives, Thailand, 3 1 pp. (in Thai, with English abstract). Kamura, S., 1989. Experimental studies on bentbic algal growth in a subtidal coral area in the Gulf of Thailand. Galaxea, 8: 217-229. Kesthong, W. and Jarayabhand, P., 1993. Study on fecundity in abalone, Haliotis ovina (Gmelin, 1791) along the eastern coast of Thailand. Presented at the 19th Congress on Science and Technology of Thailand, 27-29 October 1993, Bangkok, pp. 472-473 (in Thai, with English abstract). Mottet, M.G., 1978. A review of the fishery biology of abalones. Technical Report No. 37, March 1978, Department of Fisheries, Washington, DC. Nateewathana, A. and Bussarawit, S., 1988. Abundance and distribution of abalone along the Andaman Sea Coast of Thailand. Kasetsart J. (Sci.1, 22: 8- 15 (in Thai, with English abstract). Nateewathana, A. and Hylleberg, J., 1986. A survey on Thai abalone around Phuket Island and feasibility study of abalone culture in Thailand. Thai Fish. Gaz., 39: 177- 192 (in Thai, with English abstract). Ngow, 0. and Jarayabhand, P., 1993. Distribution and habitat selection of the abalone, Haliotis ovina (Gmelin, 17911, at the eastern coast of Thailand. Presented at the 19th Congress on Science and Technology of Thailand, 27-29 October 1993, Bangkok, pp. 472-473 (in Thai, with English abstract). Singhagraiwan, T. and Doi, M., 1992. Spawning pattern and fecundity of the Donkey’s ear abalone, observed in captivity. Thai. Mar. Fish. Res. Bull., 3: 61-69. Singhagraiwan, T. and Doi, M., 1993. Seed production and culture of a tropical abalone, Haliotis asinina Linne. The Research Project of Fishery Resources Development in the Kingdom of Thailand. The Eastern Marine Fisheries Development Center (EMFDC), Department of Fisheries, Ministry of Agriculture and Cooperatives, Thailand, 32 pp. Singhagraiwan, T. and Sasaki, M., 1991. Breeding and early development of the donkey’s ear abalone, Haliotis asinina Linne. Thai. Mar. Fish. Res. Bull., 2: 95-100. Singhagraiwan, T., Doi, M. and Sasaki, M., 1992. Salinity tolerance of juvenile Donkey’s ear abalone Haliotis asinine Linne. Thai. Mar. Fish. Res. Bull., 3: 71-77. Sungthong, S., Ingsrisawang, V. and Fujiwara, S., 199 1. Study on the relative growth of abalone, Haliotis nsinina Linne, off Samet Island. Thai. Mar. Fish. Res. Bull., 2: 15-20. Tanawansombat, S., 1992. A study on some basic biological aspects of the abalone, Haliotis ovina (Gmelin, 1791) at the eastern coast of Thailand. Special problems. Department of Marine Science, Chulalongkom University, 62 pp. (in Thai, with English abstract). Tantanasiriwong, R., 1978. An illustrated checklist of marine gastropods from Phuket Island, adjacent
168
P. Jarayabhand, N. Paphavasit/Aquaculture
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mainland and offshore island, Western Peninsular, Tbailand. Res. Bull. No. 21, Phuket Marine Biological Center, 22 pp. Tookwinas, S., Leknim, W., Donyadol, Y., Pre.edalampabuttra, Y. and Pemgmak, P., 1986. Survey on species and distribution of abalone (Haliotis spp.) in Sumttani, Nakomsrithammarat and Songkhla Provinces. Contribution No. l/1986, National Institute of Coastal Aquaculture, Department of Fisheries, Thailand, 16 pp. (in Thai, with English abstract). Uki, N., 1989. Abalone seedling production and its theory. 1. Int. J. Agric. Fish. Technol., 1: 3-15.