1. POSITION OF THE COUNTRY REPORTS
1.1 Taxonomy and ecology
Bangladesh | No report of Gracilaria spp., but it is possible that the survey done may have been limited to riverine areas. More detailed surveys towards the outer part of the bay will probably reveal some Gracilaria spp. | |
China | Scientific names appear to be correctly applied for three species - G. lemaneiformis, G. tenuistipitata and G. asiatica. Taxonomic description complete for three species. Gracilaria sp. needs verification, more materials and samples are needed. | |
Ecological data: | Complete except for depth and habitat (exposed/not exposed during low tides). | |
India | Scientific names appear to be correctly applied, except for G. crassa. Taxonomic descriptions lack information on male reproductive structures. | |
Ecological data: | Complete except for depth and habitat (intertidal/subtidal or exposed/not exposed during low tides. | |
Indonesia | Scientific names are correctly applied for G. eucheumoides and G. salicornia, but G. edulis, G. lemaneiformis and Gracilaria spp. need verification. More materials are needed. | |
Ecological data: | Lacks information on habitat, type of substrate, whether intertidal or subtidal and exposed or not during low tides. | |
Malaysia | Taxonomic description very incomplete. Needs taxonomic description of each species. The scientific names applied have to be verified, especially G. changii and Gracilaria sp. | |
Ecological data: | Notes are incomplete and should be summarised in a table. | |
Myanmar | Taxonomic description complete but the format should conform to the regular format used in taxonomic studies. The identity of G. verrucosa should be re-evaluated as this species is not found in Asia. G. crassa should be changed to G. salicornia. | |
Ecological data: | Should be condensed in the table “Summary.....”. | |
Philippines | No taxonomic description of the species which should be a major part of the report. At least the species analysed for agar should be included. The species in the data sheets are all Gracilaria sp. | |
Thailand | Taxonomic description present but incomplete. Only gross morphology of the genus is described, a more detailed description is needed. The scientific names applied are probably correct but the lack of important taxonomic characters in the description is a source of doubt. | |
Ecological data: | Lacking some ecological notes on habitat, abundance and reproductive status. | |
Vietnam | Taxonomic notes available but the binomids should be placed at the start of the description. The species need to be verified especially in the absence of note of the male structures. | |
Ecological data: | Lack of data on habitat, type of substrate and depth. |
1.2 Processing technology of Gracilaria
China | Complete analysis of agar quality in almost all of the essential parameters. In addition, different techniques of agar extraction are also reviewed and compared. Good quality agar is mostly from Gracilaria tenuistipitata collected from June to September. Although it should be noted that the values of agar content are very high and need to be verified. Due to its long experience in seaweed processing, China has a leading roles in the seaweed industry. With this expertise, they are able to help other NACA member countries to develop seaweed resources, as well as the analysis of seaweed products. | |
Culture of Gracilaria: | ||
i. | Candidates for culture: | |
• | G. asiatica | |
• | G. lemaneiformis | |
• | G. hainanensis | |
• | G. tenuistipitata var. liui | |
All of these species, especially G. asiatica and G. tenuistipitata var. liui have been studied in detail with respect to their reproduction, ecological characteristics and culture methods, as well as their agar contents and qualities. | ||
ii. | Culture methods | |
• | Intertidal culture - Suitable for all candidate species. | |
• | Floating culture - Suitable for G. asiatica, G. lemaneiformis and G. hainanensis. | |
• | Pond culture - Suitable for G. tenuistipitata var. liui because it is hard to find its sexual organs and tetrasporangia over whole seasons. It is not like G. asiatica, therefore the thalli would decay after releasing the spores and gametes. | |
iii. | Other aspects | |
• | Genetic studies. Use the experience gained on seaweed genetic studies of Laminaria and Porphyra to introduce and select new varieties with fast growth rates and higher agar quality. | |
• | Tissue culture. Develop new techniques to improve methods of spore collection. | |
India | Most of the agarophyte seaweed resources in India are G. edulis with low gel strength. As G. edulis is the major seaweed resource attempts should be made to improve agar extraction techniques. | |
i. | Candidates for culture: | |
• | G. edulis | |
• | G. tenuistipitata | |
The natural resource of G. edulis is abundant and the species is adapted to the local climate and other natural conditions, it is therefore much easier to promote local seaweed farming industries. The species, G. tenuistipitata var. liui is not mentioned in the country report. | ||
ii. | Culture methods | |
Intertidal culture and pond culture are good for Indian natural conditions. Particularly using polyculture techniques to farm seaweed and shrimp or finfish together. | ||
iii. | Suggested projects | |
Intensify studies on taxonomy and ecology of Gracilaria spp. and conduct suitable extension methods for culture. | ||
Indonesia | From the results of analysis of agar quality, there are at least two species of Gracilaria which give good agar quality in terms of gel strength, G. edulis and G. lemaneiformis. Moreover, most of the species have low gelling temperatures, which is an important characteristic of agar quality preferred for applications in microbiological mediums. There is an opportunity to develop high-value agars. Further study should be carried out on process development as well as development of the high-value agar product. Improvement of the agar extraction process should be studied to increase agar yields and clarity. | |
Malaysia | The method of agar extraction in the study was done without alkali pre-treatment and with simple processing equipment which was provided by NACA after the first workshop. However, the quality of selected agar samples showed relatively high gel strength. There is a high possibility of the process development for agar extraction to obtain an agar product with high gel strength. The support of equipment as well as training of the personnel is recommended for the development of seaweed processing technology in Malaysia since local seaweed resources are readily available and there is potential for good quality agar. | |
Myanmar | The local available species which give a similar gel quality are G. verrucosa, G. edulis and G. crassa. More development in both processing techniques and product development is recommended. More research work is needed. Support for equipment and well trained personnel should be provided. | |
Myanmar gave descriptions of 7 species: G. crassa; G. edulis; G. eucheumoides; G. foliifera; G. millardetii; G. textorii; and G. verrucosa. They also reported agar analysis from species mentioned above, except G. eucheumoides. However, ecological data was obtained from only 2 species, G. edulis and G. foliifera. Culture experiments showed that G. edulis can be grown eight months of the year with monthly harvests from April to September, suggesting commercial potential. It also grows well in the natural conditions and is suitable for culture both in inland ponds and in the open seas. | ||
Philippines | From the results of agar extraction and analysis, there are several species of Gracilaria which give good agar quality, such as G. heteroclada, G. tenuistipitata and G. firma. With high agar yields of 16–20 %, these Gracilaria species will be important raw material sources for agar production. Systematic and well-developed experience in analysis of agar is the most important resource to facilitate the development of the agar industry in the Philippines. Funding support would aid the progress of the development of the seaweed industry in the Philippines. | |
General comments on report. | ||
1. | Supply taxonomic description of species | |
2. | Supply data on: ecological parameters; gelling temperature; seasonally in reproductive states; and abundance | |
3. | Species recommended for farming include only three species G. heteroclada, G. tenuistipitata and G. firma. | |
Thailand | The Gracilaria which gave the best quality agar were G. fisheri and G. tenuistipitata which grows naturally in the southern coastal area of the country. However, the availability of the seaweed raw material is quite limited in Thailand. Incentives to farm seaweed are needed for the local coastal people to increase production. The seaweed processing industry is promoted by the Royal Thai government, for instance by the reduction of the import tax for seaweed raw materials and research funding for seaweed production and processing. The initiative of the seaweed processing industry needs to be promoted in terms of its economic, social and environmental benefits. | |
Thailand reported 7 species collected from eastern and southern Thailand: Trat, Songkhla and Pattani. They are G. changii, G. edulis, G. firma, G. fisheri, G. irregularis, G. salicornia, and G. tenuistipitata. Only 5 species, one sample each were used for agar analysis. The results show that G. fisheri and G. tenuistipitata were the most valuable followed closely by G. firma. In contrast, G. salicornia and G. changii gave lower yields and low quality agar. It was recommended that G. fisheri and G. tenuistipitata be further studied as useful resources for agar production. | ||
Vietnam | Gracilaria verrucosa gave high yields and high gel strength of agar. Improvement of the agar extraction method should be further studied with international support. Co-operation among local institutions to strengthen personnel and resource ability are recommended for the development of the seaweed processing industry in Vietnam. | |
The resource persons questioned why this study was limited to a small region in the north of the country and the exact method of extraction. There was also no data about ecological parameters of the 3 strains of G. verrucosa. |
1.3 General comments on the country reports
Vietnam and Indonesia
Ecological parameters are missing, for example, for Vietnam we do not know if samples come from culture or the wild.
What are the annual relationships between sexual maturation, growth rate and agar yield and quality.
It is essential to standardise the taxonomy, methods of measurement and extraction of agar (date of samples, water temperature, drying methods, gelling temperature etc.). It is necessary to make a Centre of Taxonomy and Methodology supervised by NACA as point of reference.
Bangladesh
Bangladesh reported an absence of Gracilaria but has recommended introduction of Gracilaria for culture. Also, they recommended studies of Hypnea and Sargassum.
1.4 Recommendations (Thailand, Myanmar and other countries)
Studies on taxonomy and ecological parameters which are important information for cultivation should be followed-up.
Collection must be done more frequently, at least once a month during the growing season.
For species determination, the male and female plants should be obtained.
Participants should give descriptions from the specimens they collected.
2. AGAR QUALITY CHARACTERISTICS OF THE DIFFERENT SPECIES IN THE COUNTRIES IN THE REGION
Quality of agar according to Japanese (Chandrkrachang and Chinadit, 1988)
Grade | Mean gel strength (g/cm2) | Species name | Mean Yield of Agar (%) | No of countries observations |
Special grade agar | 608 | G. asiatica* | 48.2 | 1 |
570 | G. lemaneiformis* | 28.48 | 2 | |
892 | G. heteroclada | 20.05 | 1 | |
649 | G. firma | 18 | 2 | |
850 | G. eucheumoides | 17 | 1 | |
758 | G. fisheri | 12.8 | 1 | |
Grade I | 578 | Gracilaria sp. * | 51.3 | 1 |
584 | G. tenuistipitata * | 22.2 | 4 | |
356 | G. salicornia | 11 | 3 | |
565 | Gracilaria sp. | 10.1 | 1 | |
Grade II | 278 | G. blodgettii | 26.5 | 1 |
290 | G. chorda | 21.5 | 1 | |
257 | G. changii | 20.0 | 3 | |
292 | G. verrucosa | 20 | 2 | |
250 | G. fastigiata | 19.3 | 1 | |
280 | G. edulis o | 15.3 | 3 | |
Grade III | 34.4 | G. corticata var. corticata o | 22.4 | 1 |
- | Gracilaria sp. | 22.4 | 1 | |
47.2 | G. corticata var cylindrica o | 19.8 | 1 | |
128 | G. bursa-pastoris | 15.7 | 1 | |
85 | G. textorii | 15 | 1 | |
76 | G. millardetii | 14.5 | 1 | |
64.5 | G. foliifera | 13.9 | 1 | |
62.4 | G. crassao | 12.1 | 2 |
+ The countries involved are Bangladesh, China, India, Indonesia, Malaysia, Myanmar, Philippines, Thailand and Vietnam.
3. SUMMARY OF RESULTS ON GRACILARIA SPECIES
Table 3.1: China
Table 3.2: India
Table 3.3: Indonesia
Table 3.4: Malaysia
Table 3.5: Myanmar
Table 3.6: Philippines
Table 3.7: Thailand
Table 3.8: Vietnam
3.1 Summary of Results on Gracilaria Species in China
Species | Date | ECOLOGICAL PARAMETERS | AGAR YIELD AND QUALITY | Remarks | ||||||||||
Abundance | Salinity (ppt) | Temp (°C) | Substrate | Depth (cm) | Rep. Stage | Yield (%) | Gel strength (g/cm2) | Gelling Temp. (°C) | Melting Temp. (°C) | Method of extraction | Code (Table IV, Country Report) | |||
G. lemaneiformis | 1-6-94 | + | 28.6–31.0 | 23–26 | Rocky | Y | 46.4 | 848 | 93.5 | 5%NaOH | 1A | Quingdao | ||
G. lemaneiformis | 27-8-94 | + | Rocky | Y | 47.6 | 872 | 91.0 | " | 1B | Quingdao | ||||
G. asiatica | 1-6-94 | + | 28.6–31.0 | 23–26 | Rocky-sand | 44.1 | 682 | 80.0 | " | 2A | Quingdao | |||
G. asiatica | 24-7-94 | + | Rocky-sand | Y | 52.3 | 534 | 92.0 | " | 2B | Quingdao | ||||
G. tenuistipitata | 26-6-94 | +++ | 28.5 | 30.2 | Muddy-sand | Y | 38.2 | 482 | 92.5 | " | 3A | Shanyao | ||
G. tenuistipitata | 31-7-94 | + | 32.3 | 31.0 | Muddy-sand | 44.7 | 634 | 95.0 | " | 3B | Shanyao | |||
G. tenuistipitata | 3-9-94 | + | 23.0 | 29.0 | Muddy-sand | 35.0 | 1001 | 103.2 | " | 3C | Shanyao | |||
Gracilaria sp. | 17-7-94 | +++ | 28.3 | 37–39 | Muddy-sand | V.P. | 48.7 | 609 | 96.8 | " | 4B | Dongshan Island | ||
Gracilaria sp. | 17-7-94 | +++ | 24.2 | 37–39 | Muddy-sand | V.P. | 57.5 | 578 | 93.0 | " | 4C | Dongshan Island | ||
Gracilaria sp. | 20-8-94 | +++ | 23.1 | 28–29 | Muddy-sand | V.P. | 47.6 | 549 | 94.0 | " | 4D | Dongshan Island | ||
G. tenuistipitata v. liui | 26-6-94 | +++ | 11.7 | 34.7 | Muddy-sand | V.P. | 49.7 | 363 | 93.5 | " | 5A | Quiantou | ||
G. tenuistipitata | 15-6-94 | +++ | 20.4 | 29 | Muddy-sand | V.P. | 38.0 | 720 | 99.2 | " | 5B | Diancheng | ||
G. tenuistipitata | 18-8-94 | 0 | 27.2 | Muddy-sand | V.P. | 33.3 | 446 | 97.2 | " | 5C | Diancheng | |||
G. tenuistipitata var. liui | 16.-8-94 | +++ | 7.33-8.62 | 29.2-31.0 | Sandy-mud | V.P. | 44.9 | 373 | 92.8 | " | 7A | Rongshan | ||
G. tenuistipitata var. liui | 12-6-94 | + | 22.1 | 33–36 | Muddy | V.P. | 42.8 | 360 | 94.5 | " | 8A | Beihai |
Y | = | Reproductive structures present |
V.P. | = | Vegetative propagation. |
3.2 Summary of Results on Gracilaria Species in India
Species | Date | ECOLOGICAL PARAMETERS | AGAR YIELD AND QUALITY | Remarks | |||||||||
Abundance | Salinity (ppt) | Temp (°C) | Substrate | Depth | Rep Stage | Yield (%) | Gel strength (g/cm2) | Gelling Temp. (oC) | Melting Temp. (oC) | Method of extraction | |||
G. edulis | 4-6-92 | +++ | 31.5 | 30 | Sand/coral | Y | 17 | 34.69 | 95 | 5% NaOH | |||
G. edulis | 14-8-92 | + | 35.84 | 28.4 | Sand/coral | N | 15.4 | 62.69 | 95 | " | |||
G. edulis | 29-9-92 | + | 34.62 | 29.2 | Sand/coral | Y | 20.8 | 58.69 | 94 | " | |||
G. edulis | 24-12-92 | + | 32.46 | 27.4 | Sand/coral | N | 13.6 | 34.69 | 95 | " | |||
G. edulis | 6-2-93 | +++ | 34.56 | 26.0 | Sand/coral | Y | 16.4 | 31.69 | 95 | ||||
G. edulis | 23-4-93 | + | 35.86 | 32.4 | Sand/coral | Y | 10.6 | 58.69 | 94 | ||||
G. edulis | 28-5-94 | +++ | 30.8 | 29.6 | Sand/coral | Y | 14.8 | 52.69 | 97 | ||||
G. edulis | 24-6-94 | +++ | 35.2 | 27.6 | Sand/coral | Y | 14.2 | 52.69 | 98 | ||||
G. edulis | 12-7-94 | +++ | 34.6 | 27.4 | Sand/coral | Y | 19.4 | 113.69 | 98 | ||||
G. edulis | 10-8-94 | +++ | 35.6 | 28.6 | Sand/coral | Y | 93.69 | 98 | |||||
G. edulis | 6-9-94 | +++ | 34.6 | 29.2 | Sand/coral | Y | 19.8 | 98.69 | 98 | ||||
G. corticata var. corticata. | 27-5-94 | +++ | 32.4 | 29.4 | Rocky | Y | 18.8 | 32.69 | 98 | " | |||
G. corticata var. cylindrica | 23-6-94 | +++ | 35.2 | 27.6 | Rocky | Y | 30.8 | 44.69 | 98 | ||||
G. crassa | 23-7-94 | +++ | 34.6 | 27.6 | Rocky | Y | 17 | 34.62 | 98 | ||||
G. corticata var. corticata | 24-8-94 | +++ | 34.8 | 28.4 | Rocky | Y | 25.0 | 38.69 | 98 | 5% NaOH | |||
G. corticata var. corticata | 15-9-94 | +++ | 34.26 | 29.6 | Rocky | Y | 15.8 | 31.69 | 95 | " | |||
G. corticata var. cylindrica | 28-5-94 | +++ | 30.8 | 29.6 | Sand/rock | Y | 18.4 | 36.69 | 98 | " | |||
G. corticata var. cylindrica | 24-6-94 | +++ | 31.2 | 27.6 | Sand/rock | Y | 24.6 | 65.69 | 98 | " | |||
G. corticata var. cylindrica | 12-7-94 | +++ | 34.6 | 27.4 | Sand/rock | Y | 25.2 | 58.69 | 98 | " | |||
G. corticata var. cylindrica | 10-8-94 | +++ | 35.6 | 28.4 | Sand/rock | Y | 14.8 | 36.69 | 98 | " | |||
G. corticata var. cylindrica | 6-9-94 | +++ | 34.62 | 28.6 | Sand/rock | Y | 20.8 | 40.60 | 98 | " | |||
G. crassa | 27-5-94 | +++ | 32.4 | 29.4 | Stone pieces | Y | 5.6 | 28.69 | 98 | 5% NaOH | |||
G. crassa | 29-6-94 | +++ | 33.6 | 27.8 | Stone pieces | Y | 5.4 | 27.69 | 98 | " | |||
G. crassa | 12-7-94 | +++ | 33.8 | 28.2 | Stone pieces | Y | 7.8 | 28.69 | 98 | " | |||
G. crassa | 10-8-94 | +++ | 35.4 | 28.4 | Stone pieces | Y | 5.1 | 29.69 | 98 | " | |||
G. crassa | 7-9-94 | +++ | 34.42 | 28.8 | Stone pieces | Y | 6.2 | 29.69 | 98 | " |
3.3 Summary of Results on Gracilaria Species in Indonesia
Species | Date | ECOLOGICAL PARAMETERS | AGAR YIELD AND QUALITY | Remarks | |||||||||
Abundance | Salinity (ppt) | Temp (°C) | Substrate | Depth (cm) | Rep Stage | Yield (%) | Gel strength (g/cm2) | Gelling Temp. (°C) | Melting Temp. (°C) | Method of extraction | |||
G. edulis | 20-9-92 | ++ | 28 | 29 | 8.13 | 610 | 36 | 68 | SW 01 | ||||
G. edulis | 8-10-92 | +++ | 29 | 29 | 13.61 | 840 | 39 | 90 | SW 03 | ||||
G. edulis | 15-6-93 | +++ | 29 | 28 | 15.77 | 575 | 32 | 79 | SW 10 | ||||
G. lemaneiformis | 20-9-94 | +++ | 28 | 29 | 9.96 | 880 | 34 | 85 | SW 02 | ||||
Gracilaria sp. | 9-10-92 | ++ | 29 | 29 | 8.18 | 780 | 28 | 86 | SW 04 | ||||
Gracilaria sp. | 4-6-93 | + | 33 | 28 | 12.12 | 550 | 28 | 89 | SW 09 | ||||
G. saliconia | 21-5-93 | ++ | 31 | 28 | 5.47 | 580 | 32 | 75 | SW 05 | ||||
G. saliconia | 4-6-93 | + | 33 | 28 | 11.07 | 625 | 31 | 72 | SW 08 | ||||
G. eucheumoides | 21-5-93 | + | 31 | 28 | 16.99 | 850 | 29 | 32 | SW 06 |
3.4 Summary of Results on Gracilaria Species in Malaysia
Species | Date | ECOLOGICAL PARAMETERS | AGAR YIELD AND QUALITY | Remarks | ||||||||||
Abundance | Salinity (ppt) | Temp (°C) | Substrate | Depth (m) | Rep Stage | Yield (%) | Gel strength (g/cm2) | Gelling Temp. (°C) | Melting Temp. (°C) | Method of extraction | ||||
G. changii | 001 | 13-5-92 | 28 | 28 | 41.7 | Non alc treat | ||||||||
G. changii | 002 | 28-5-92 | 32 | 28 | 4m | 39 | " | T = 90 cm | ||||||
G. changii | 003 | 9-7-92 | 32 | 28 | 4m | 35.8 | " | T = 85 cm | ||||||
G. changii | 004 | 9-9-92 | 32 | 30 | 1.5m | 30.5 | " | T=115cm | ||||||
Hypnea sp. | 005 | 9-9-92 | 28 | 29 | 1.5m | 13.5 | " | T=115cm | ||||||
G. changii | 006 | 24-4-93 | 28–32 | 28–30 | sandy/muddy | 20 | " | Sheltered, not exp. | ||||||
G. fastigiata | 007 | 24-4-93 | 30 | 29 | 2.5m | 15.8 | 89 | " | Sheltered, exp. (T=28 cm) | |||||
G. changii | 008 | 14-5-93 | 28–32 | 28–30 | 3.8m | 25.4 | 174 | " | Sheltered, not exp. (T=80 cm) | |||||
Gracilaria sp. | 009 | 14-4-94 | muddy | 20.4 | " | Sheltered, exp. | ||||||||
Gracilaria sp. | 010 | 27-7-94 | muddy | 24.4 | " | Sheltered, exp. | ||||||||
G. changii | 011 | 17-9-94 | 28–30 | shrimp pond | 25.2 | " | Sheltered, not exp. | |||||||
G. changii | 012 | 8-10-94 | shrimp pond | 22.1 | " | Sheltered, not exp. |
Key: exp. = exposed at low tide.
not exp.: = not exposed at low tide. T = turbidity
3.5 Summary of Results on Gracilaria Species in Myanmar
ECOLOGICAL PARAMETERS | AGAR YIELD AND QUALITY | |||||||||||||
Species | Date | Abundance | Salinity (ppt) | Temp (°C) | Substrate | Depth (cm) | Rep Stage | Yield (%) | Gel strength (g/cm2) | Gelling Temp. (oC) | Melting Temp. (°C) | Method of extraction | Code: NACA- | |
G. verrucosa | 9–22 | 62–120 | 27–40 | 52–70 | 2–6%NaOH | 001 | Rakhine/ Thanithari | |||||||
G. edulis | 10–22 | 60–120 | 27–39 | 52–73 | " | 002 | Rakhine/ Thanithari | |||||||
G. crassa | 12–21 | 70–120 | 28–40 | 55–73 | " | 003 | Rakhine/ Thanithari | |||||||
G.foliifera | 11–19 | 60–98 | 18–39 | 50–82 | " | 004 | Rakhine/ Thanithari | |||||||
G. millardetii. | 10–19 | 60–92 | 29–39 | 50–80 | " | 005 | Rakhine/ Thanithari | |||||||
G. textorii | 11–19 | 60–110 | 27–39 | 52–73 | " | 006 | Rakhine/ Thanithari | |||||||
G. edulis | 23-8-92 | Dominant | - | 26.0 | Rocky | 10 | - | 18.22 | 92.51 | 64–69 | wild | Mushwe-key, Rakhine 9/92 | ||
G. edulis | 24-11-92 | Dominant | - | 18.87 | polythene rope | 0–100 | - | 18.87 | 116.5 | 45–62 | cultured | 3/92. | ||
Mushwe-key, Rakhine | ||||||||||||||
G.foliifera | 18-2-92 | Dominant | - | 12.85 | Rocky | inter-tidal | - | 12.85 | 50.07 | 73–74 | wild | 1/93. Martin Point, Rakhine | ||
G. edulis | 18-2-92 | Dominant | - | 22.18 | Rocky | inter-tidal | - | 22.18 | 116.91 | 68–71 | wild | 2/93 Martin Point, Rakhine |
3.6 Summary of results on Gracilaria species in the Philippines
Species | Date | ECOLOGICAL PARAMETERS | AGAR YIELD AND QUALITY | ||||||||||
Abundance | Salinity (ppt) | Temp (°C) | Habitat | Depth (cm) | Rep Stage | Yield (%) | Gel strength (g/cm2) | Gelling Temp. (°C) | Melting Temp. (°C) | Method of extraction | Remarks | ||
% SO42- | |||||||||||||
G.fastigiata | ++ | 25–35 | 25–35 | open reef flat Sandy/rocky | not? | 19.24 | 250 | - | 79 | 5%NaOH | 3.28 | ||
G. saliconia | + | 25–35 | 25–35 | open reef flat Sandy/rocky | c.c. | 20.07 | 287 | - | 80 | 5%NaOH | 1.86 | ||
G. changii | ++ | 25 | 34 | open reef flat Coral | c.c. | 20.67 | 583 | 86 | 5%NaOH | 0.56 | |||
G. tenuistipitata | ++ | 10–25 | 25–33 | Brackish. Sandy-mud | c.c | 16.18 | 726 | 88 | 5%NaOH | 1.26 | |||
G.firma | +++ | 25–35 | 25–35 | Mangrove Sandy-mud | c.c (nov) | 17.61 | 606 | 89 | 5%NaOH | 0.22 | |||
G. heteroclada | ++ | 10–25 | 25–33 | Brackish pond -mud. | n.o. | 20.05 | 892 | 92 | 5%NaOH | 0.45 |
3.7 Summary of results on Gracilaria species in Thailand
Species | Date | ECOLOGICAL PARAMETERS | AGAR YIELD AND QUALITY | Remarks | ||||||||||
Abundance | Salinity (PPO | Temp (°C) | Substrate | Depth (cm) | Rep Stage | Yield (%) | Gel strength (g/cm2) | Gelling Temp. (°C) | Melting Temp. (°C) | Method of extraction | Code: NACA- | |||
G.firma | 28-4-93 | 31 | 34 | Sandy-mud | - | - | - | 3%NaOH | 001 | Trat | ||||
G. changii | 28-4-93 | 33 | 37 | Sandy-mud | exposed | - | - | " | 002 | Trat | ||||
G. irregularis | 28-4-93 | 33 | 37 | Sandy-mud | exposed | - | - | " | 003 | Trat | ||||
G. edulis | 28-4-93 | 33 | 37 | Sandy-mud | 10–20 | - | - | " | 004 | Trat | ||||
G. salicornia | 28-4-93 | 31 | 34 | Sandy-mud | 30–50 | - | - | " | 005 | Trat | ||||
G. salicornia | 8-6-93 | - | - | Sandy-mud | 30–50 | 4.75 | 180 | 88 | " | 006 | Trat | |||
G. changii | 8-6-93 | 32 | - | Sandy-mud | - | F | 9.50 | 190 | 90 | " | 007 | Trat | ||
G. firma | 4-4-94 | 33.5 | 36 | Sandy-mud | 30 | F | 19.96 | 692 | 93 | " | 008 | Songkhla | ||
G.fisheri | 21-8-94 | 11 | - | Muddy sand | 100 | F | 12.84 | 758 | 94 | " | 009 | Songkhla | ||
G. tenuistipitata | 20-8-94 | 31 | - | Muddy sand | 30 | F | 12.70 | 768 | 98 | " | 010 | Songkhla |
3.8 Summary of results on Gracilaria species in Vietnam
Species | Date | ECOLOGICAL PARAMETERS | AGAR YIELD AND QUALITY | Remarks | ||||||||||
Abundance | Salinity (ppt) | Temp (°C) | Substrate | Depth (cm) | Rep Stage | Yield (%) | Gel strength (g/cm2) | Gelling Temp. (°C) | Melting Temp. (°C) | Method of extraction | ||||
G. verrucosa | 20-6-92 | +++ | 15–16 | 23 | 50 | Nov–Jul | 29.5 | 516 | - | 2–4%NaOH | Dinh vu, Haiphong | |||
G. blodgettii | 27-5-93 | +++ | 23 | 24 | Muddy-sand | 70 | Mar–Jul | 26.5 | 278 | 85–87 | " | Phulong, Haiphong | ||
G. tenuistipitata | 21-6-92 | +++ | 16 | 22–24 | Rocky | 50 | Jan–Jun | 19.7 | 338 | 89–92 | " | Lienvi, Quangninh | ||
G. chorda | 28-5-93 | ++ | 23 | 22 | Rocky | 85 | Jan–Jul | 21.5 | 290 | 85–87 | " | Haininh, Quangninh | ||
G. arcuata | 7-5-93 | ++ | 22 | 23 | Rocky | 85 | Mar–Jul | 17.6 | 258 | 92–93 | " | Dovon, Haiphong | ||
G. bursa-pastoris | 7-5-93 | ++ | 26 | 23 | Rocky | 85 | Jan–Jul | 15.7 | 128 | 92–93 | " | Quanlan, Quangninh | ||
G. verrucosa | (1) | 20-6-92 | ++ | 16 | 23 | Rocky | 50 | Nov–Jun | 29.5 | 516 | 82–85 | " | Dinh vu, Hai Phong | |
(2) | 20-6-92 | ++ | 16 | 23- | - | 27.0 | 456 | - | " | Bang la, Haiphong | ||||
(3) | - | - | - | - | - | 24.5 | 319 | - | " | Cathai, Hiaphong | ||||
(4) | 20-6-92 | ++ | 15 | 23 | Rocky | 45 | Jan–Jul | 31.0 | 474 | 82–85 | " | Yin hung, Quang Ninh | ||
(5) | 20-6-92 | - | 15 | 23- | Rocky | 50 | - | 28.0 | 396 | - | " | Thai thuy, Thai binh | ||
(6) | 20-6-92 | - | - | - | Rocky | - | 26.9 | 387 | - | " | Hai hau, Nam Ha. | |||
G. gigas | 28-5-93 | ++ | 25 | 23 | Rock/sand | 80 | Jan–July | Campha, Quangninh |
4. SEAWEED PROCESSING TECHNOLOGY IN PARTICIPATING COUNTRIES
4.1 China
Methods used for Agar Extraction
G. tenuistipitata
First Method of Extraction
Second Method of Extraction
25% NaOH treatment, the rest same as 1st method
Third Method of Extraction
4.2 India
Gracilaria species1 | |
G. edulis | (11) |
G. crassa | (6) |
G. corticata var. cylindrica | (9) |
Method of Extraction
1 Numbers within brackets indicate the number of samples
4.3 Indonesia
Gracilaria species | |
G. edulis | (3) |
G. lemaneiformis | (0) |
G. spp. | (2) |
G. salicornia | (2) |
G. eucheumoides. | (0) |
Method of Extraction
Adopted from Chandrkrachang, 1992
Water extraction as the first step, then alkali treatment to the agar afterwards.
4.4 Malaysia
Gracilaria species | |
G. changii | (8) |
G.fastigiata | (1) |
G. spp. | (2) |
Hypnea sp. | (1) |
Method of Extraction
4.5 Myanmar
Gracilaria species
G. verrucosa
G. edulis
G. crassa
G.foliifera
G. millardetii
G. textorii
Method of Extraction
4.6 Philippines
Gracilaria species | |
G. fastigiata | (8) |
G. salicornia | (2) |
G. spp. | (3) |
G. changii | (9) |
Method of Extraction
4.7 Thailand
Gracilaria species | |
G. salicornia | (1) |
G. changii | (1) |
G.firma | (1) |
G. fisheri | (1) |
G. tenuistipitata | (1) |
Method of Extraction
4.8 Vietnam
Gracilaria species | |
G. verrucosa | (7) |
G. blodgetti | (1) |
G. tenuistipitata | (1) |
G. chorda | (1) |
G. arcuata | (1) |
G. bursa-pastoris | (1) |
Method of Extraction