37. To provide comprehensive guidelines for discussion and the formulation of recommendations, resource persons were invited to present and discuss specialist papers in the fields of taxonomy, ecology and culture, processing, phytosanitation and environment, marketing and trade, and socio-economics. Summaries of the papers are presented below:
38. A review paper on the taxonomy of Gracilaria in Asian countries. Presented by Prof. Khanjanapaj Lewmanomont. Faculty of Fisheries. Kasetsart University. Thailand. In reports from countries in the region, only Bangladesh reported the absence of Gracilaria. Reports from the eight other countries, namely: China; India; Indonesia; Malaysia; Myanmar; Philippines; Thailand; and Vietnam, included 23 identified species with 3 varieties and 6 unidentified species. Among these, 10 species seem to be correctly identified, while the rest have to be confirmed. The most common species was G. edulis, followed by G. tenuistipitata, G. salicornia and G. changii. The species recommended for culture were G. edulis, G. changii and G. tenuistipitata.
39. The problem in identifying the species of Gracilaria is the lack of sexual reproductive organs. Only a few species can be identified by their morphological characteristics, such as G. eucheumoides and G. salicornia.
The paper by Professor Khanjanapaj appears as Annex IV-1.
40. Cultivation and uses of Gracilaria Presented by Dr. Olivier Barbaroux, IFREMER, Centre de Nantes. Nantes Cedex 01, France. The phycoculture of Gracilaria has four objectives: (i) fodder for fish and mollusc aquaculture; (ii) human consumption; (iii) fertiliser; and (iv) high quality agar. Chinese and Philippine fish farmers were probably the first to cultivate it by throwing the algae (cut in little pieces) into ponds where herbivorous fishes (such as milkfish) are grown. Gracilaria verrucosa was not considered an agarophyte before 1949 when Japanese agar ran short and agar extraction using alkali treatment was developed. Since that time, production has steadily increased. Despite the simplicity of culture, two major problems restrict the production of a high commercial quality agar biomass. Firstly, taxonomic problems due to the difficulties encountered in reliably determining species and secondly increasing the culture yields usually lowers the agar quality and vice versa. The presentation was supplemented by a slide presentation showing various culture methods and processing techniques in various countries including China, the Philippines, Vietnam, and Chile.
The paper by Dr Perez and Dr Barbaroux appears as Annex IV-2.
41. A review of Gracilaria culture in Asia-Pacific and directions for future development. Presented by Dr. Gavino Trono; Jr., Marine Science Institute. College of Science. University of the Philippines. This paper described the current status of the culture of Gracilaria in the region, the different methods presently used in its culture and production of planting materials. It outlined various courses of action for future development.
The paper by Dr Trono appears as Annex IV-3.
42. Taxonomy and culture of Gracilaria in the Asia-Pacific region. Presented by Prof. Chen Jiaxin, Yellow Sea Fisheries Research Institute. Qingdao. China. This review combines the country reports presented by China, India, Myanmar and Vietnam and literature on the genus Gracilaria. Detailed biological characteristics of Gracilaria species, including basic features for taxonomy, life cycle and ecological conditions for cultivation are described. Sixty five species of Gracilaria and their distribution in the region are listed and 25 species are described in detail. Culture methods, such as pond culture and floating-raft culture, are briefly described.
The paper by Prof. Chen Jiaxin and Xia Bang Mei appears as Annex IV-4.
43. Delimitation of species and population genetic structure in Gracilaria verrucosa: Consequences for cultivation. Presented by Dr. Christophe Destombe. Laboratoire de Genetique et Evolution des Populations Vegetales, URA CNRS, Universite de Lille l, Ascq Cedex, France. Species of Gracilaria are some of the most useful algae in the world, combining the production of valuable agar with a fast growth rate, ease of vegetative production and other attributes favouring their cultivation. When planning to farm these red algae in new areas, it is essential to identify the species and to be aware of the biology of the species considered. In agarophytes, delimitation of species is very difficult using available morphological characteristics and the biology of the species generally depends on local adaptation.
44. The paper describes (i) the new molecular tools to delineate species of Gracilaria using sequences of cytoplasmic and nuclear DNA, (ii) the level and pattern of population genetic structuring and the possibility for local adaptation in Gracilaria verrucosa using two methods. First, crossing experiments to study the crossing compatibility depending on the distance between male and female gametophytes and, secondly, molecular analysis to study the distribution of the genetic markers within and between populations. These studies reveal that Rubisco spacer analysis is a good method to delimit the species and that genetic divergence could occur between populations of Gracilaria verrucosa, even at short distances (about 100m). Consequently, it is very important before planning cultivation to be aware of the origin of the Gracilaria verrucosa inoculum to use in breeding experiments and farming.
The paper by Dr Destombe appears as Annex IV-5.
45. Gracilaria studies at SEAFDEC Aquaculture Department. Presented by Dr. A. O. Hurtado-Ponce, Scientist SEAFDEC/AQD, Tigbauan, Iloilo, Philippines. Research on seaweed during 1988–1994 focused on Gracilaria species. Studies were made on the following areas: inventory of seaweed resources; production-ecology; farming systems; and agar characterisation. Six species of Gracilaria and one Gracilariopsis abound in the Western Visayas region. Monthly variations in biomass and agar quality were recorded in G. changii, G. manilaensis, and Gracilariopsis heteroclada collected at different places. However, only G. heteroclada was found throughout the year.
46. Most of the studies were carried out on G. heteroclada because of its wide distribution, fast growth characteristics and good quality agar. Its reproductive state was seasonal with tetrasporophyte abundant in May and carposporophyte in January. Harvesting 75% of the available biomass was sufficient to maintain “seedstock” for the next cropping season. Harvesting using “arana” was not appropriate in places where the biomass is exposed to air during lowest tide. The addition of nutrients to the stock increased the growth rate of the plant and gel strength of its agar. G. heteroclada grown at lower stocking density in hapa nets, both in floating cages and in ponds, gave higher growth rates and production than at higher stocking densities. Polyculture with Penaeus monodon at lower stocking density combinations gave the highest growth rate and income. Encouraging results were observed when cultured vertically in ropes inside a floating cage. Culture at 24–25 ppt under tank conditions produced the highest gel strength.
The paper by Dr Hurtado-Ponce appears as Annex IV-6.
47. An overview of seaweed processing technology for Gracilaria with reference to agar yield and quality. Presented by Dr. Suwalee Chandrkrachang. Asst. Professor. Biopolymer Research Unit of the Department of Chemistry, Faculty of Science, Srinakarinvirot University. Thailand. Seaweeds are valuable to both the economy and environment of many countries. The processing of seaweeds into phycocolloids became the foundation of a major world-wide industry involving the manufacture of food, cosmetics, drugs and products of biotechnology. The most valuable product of phycocolloids is agar, which is produced from red seaweeds of the genus Gracilaria, involving different species. Agar consists of heterogeneous biopolymers containing galactose units and their derivatives. Varying market prices of the agar result from different grades, which depend on the gel strength, clarity and the quantities of the charged particles in the agar.
48. Different agar extraction techniques were reviewed. Samples of seaweed and agar from the countries participating in the regional study were analysed at BRU. The results will be used to develop guidelines for improving both the quality and quantity of the seaweed raw materials and their agar products which are essential information for research and industry development. The presentation offered advice on the essential considerations in setting up a processing plant for agar.
The paper by Dr Suwalee appears as Annex IV-7.
49. Future directions in Gracilaria research and valorisation. Presented by Prof. Annette Alfsen. Directeur de Recherche. CNRS. Universite Rene Descartes. Paris. The research currently carried out in co-operation with Dr. Suwalee Chandrkrachang from Bangkok (Srinakarinvirot University) deals with the protein content of different samples of Gracilaria spp. growing or cultivated in Thailand. Amino acids were analysed to select the best species for preparation of proteins on an industrial scale from these algae. Such proteins could be used in human and animal food with the same advantages as vegetal proteins, at low cost to countries lacking in animal proteins in Asia. The extraction of proteins has to be carried out after the extraction of agar, adding value to the production of cultivated Gracilaria spp. Study and extraction of lipid with polyunsaturated fatty acids essential in children's nutrition have to be planned also from Gracilaria sp. Further, the preparation of enriched endocytic vesicles, cell organelles previously isolated and studied in other algae, has to be set up from these algae to develop their use in pharmacology. Studies have shown that there are possibilities for using such materials as drug carriers.
The paper by Prof. Alfsen appears as Annex IV-8.
50. Phytosanitation - Utilisation of Gracilaria in reclamation of shrimp pond effluents. Presented by Mr. Kanit Chaiyakam. National Institute of Coastal Aquaculture. Songkhla. Thailand. Experiments using Gracilaria fisheri for biological wastewater treatment of shrimp pond effluent was conducted by static bioassay with indoor tanks of 200 litres in size. The results of the first experiment showed that values of B.O.D, C.O.D., total ammonia, nitrate, total settleable solids and chlorophyll a. decreased over 24 and 48 hrs. The second experiment showed similar trends and confirmed the results of the first experiment. Experiments have also been done using Gracilaria sp. in combination with green mussel (Mytilus sp.) for biological water treatment and also some field trials in Lake Songkhla for reducing nutrient load in proximity to the finfish cages. The results are encouraging and confirm the phytosanitation value of Gracilaria spp.
The abstract of the paper by Mr Kanit appears as Annex IV-9.
51. International and regional trade in seaweeds and seaweed products, with special reference to Gracilaria and agar quality standards. Presented by Mr. Suchart Wongwai. Chemical Goods Section. Port Authority of Thailand. Bangkok. Gracilaria. is the major raw material for the agar industry in the world. Chile is the largest Gracilaria producer and Japan the largest agar producer and consumer. World agar production is estimated at 10,000 tonnes a year and about half is from Gracilaria. Thailand, Malaysia and Indonesia are major importers of agar and are also attempting to produce agar locally, but lack of raw materials and know-how are major drawbacks. Vietnam can produce a great deal of Gracilaria and has an agar industry, but agar quality needs to be improved. The price of Gracilaria is increasing year by year and agar, both of commercial and bacterial grade, is expensive. Japan, South Korea and Taiwan are top agar producers, labour and land costs in these countries are among the reasons for the increase in the price of agar. To save on these costs Japan is now setting up agar factories in other Asian countries.
The paper by Mr Suchart appears as Annex IV-10.
52. Socio-economics of a coastal community in the Philippines with Gracilaria seaweed production as an alternative livelihood. Presented by Nyan Taw. Chief Technical Adviser. Seaweed Production Development Project Philippines. The estimated income level of coastal households in Sorsogon ranges from 2000 to 3560 Pesos1 per month. About 39% of the population are engaged in fishing, which is their main source of income. Studies in the coastal areas of Sorsogon have revealed that the area is rich in Gracilaria resources both in quality and quantity. Three types of areas with their specific environmental conditions were found for Gracilaria farming purposes. They are: (i) open sea coralline flats with high salinity (ii) bays along coast line with sandy muddy substrate and with high salinity and (iii) brackishwater ponds with muddy substrates and low salinity. Three methods of farming have been developed, namely - fixed bottom line, floating raft line and pond culture. Simple (family sized) processing technology to produce one kg per day of food agar powder was also developed. Utilising the technologies that developed coastal communities have initiated, Gracilaria farming and processing activities have been promoted as an alternative livelihood, with local government support. The unit cost to produce one kg of dried Gracilaria is estimated at 3.20 Pesos per kg with the selling price of between 6.00 to 10.00 Pesos, while the unit cost to produce one kg of agar powder is estimated at 406.20 Pesos with the selling price of between 750.00 and 1000 Pesos. The potential for farming and processing Gracilaria has not yet been fully utilised in the Philippines.
53. Gracilaria production and trade (extracted from faxed input from INFOFISH). Total world production of agar is estimated at 7,000–10,000 tonnes, half of it originating in Japan and Republic of Korea. The major producing countries are Japan, Spain, Chile and Republic of Korea. Several leading agar producers export most of their production. Emerging producers in the Asia-Pacific region are Indonesia, the Philippines and Thailand.
The input from INFOFISH appears as Annex TV-11.
1 25 Pesos= 1 US$ Approximately
