SPC/Inshore Fish. Res./WP.12 11 March 1988 ORIGINAL : ENGLISH

SOUTH PACIFIC COMMISSION

WORKSHOP ON PACIFIC INSHORE FISHERY RESOURCES (Noumea, New Caledonia, 14 - 25 March 1988)

DEVELOPMENT OF PHYCOCOLLOID-RELATED INDUSTRIES IN

BY

STEPHEN G. NELSON Marine Laboratory University of Guam Mangilao, Guam 96923 USA

ABSTRACT

There is regional interest in the development of marine industries involving the production and harvest of seaweeds for the extraction of phycocolloids. Two groups of benthic marine have received particular attention. These are agarophytes of the genera Gracilaria and Polycavernosa and carrageenan- bearing species of the genus Eucheuma. Although documentation of algal standing stocks and productivity of economic seaweeds within the region is poor, it*seems unlikely that there are sufficient natural algal stocks to support processing plants for phycocolloids. An alternative to the harvest of wild crops of seaweeds is to develop seaweed farms to raise economically valuable species. The cultivation of seaweeds for phycocolloid production would seem well-suited for remote areas within the region since the seaweeds can be sun-dried, stored for long periods and shipped by boat. However development should proceed with caution and should be preceded by careful analyses of marketing and economics. This should include the development of strategies for penetrating the existing markets.

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INTRODUCTION The benthic marine macrophytes of Oceania constitute an undeveloped economic resource. The commercial uses of seaweeds are varied, but the major interest within the region lies in the culture and harvest of seaweeds for use in the production of phycocolloids. This interest stems from the growing world-wide demand for phycocolloids, particularly for and carrageenan, and from the successful establishment of commercial farms for seaweeds in Taiwan, the Philippines and other tropical areas. This interest has motivated the establishment of several research, development and demonstration projects within the region aimed at the production of phycocolloid-bearing seaweeds. The purpose of this document is to review the technical literature relevant to the development of regional industries involving the use of seaweeds for the production of phycocolloids, and to identify areas where additional information is needed. The literature survey is not exhaustive, rather the works cited were chosen as regional examples of the issues raised, and to provide a starting place for those wishing additional information. RESOURCE BIOLOGY Taxonomy The benthic algae of interest in regard to development of a phycocolloid industry are in the order Gigartinales of the division Rhodophyta, the . These are the agar-bearing species of the genera Gracilaria and Polycavernosa, within the family Gracilariaceae, and the carrageenan-producing species of the genus Eucheumaf within the family Soleriaceae. Some taxonomic confusion exists within each of these groups, and a phycological workshop was recently convened at the University of Guam in order to address this problem. The results of the workshop include information on the taxonomy of Eucheuma (Doty, 1985; Doty and Norris, 1985), Gracilaria (Tsuda, 1985; Fredericg and Norris, 1985), and Polycavernosa (Xia and Abbott, 1985) relevant to those working in the tropical Pacific. The recent work of Meneses and Abbott (in press) discusses, in detail, the taxonomy of the genera Gracilaria and Polycavernosa within Micronesia.

Geographical distribution Species of Gracilaria, Polycavernosa, and Eucheuma occur naturally in the shallow waters surrounding volcanic islands; they usually do not occur near atolls (Tsuda, 1982). Phycological works concerning Micronesia are listed in the bibliographies of Tsuda and Wray (1977) and Tsuda (1981). Likewise, phycological bibliographies are available for French Polynesia (Payri and Meinesz, 1985) and New Caledonia (Garrigue and Tsuda, in press). Other distributional accounts of marine algae within the region include those of Womersley and Bailey Page 3

(1970), for the Solomon Islands, and of Chapman (1971), for Fiji. Prakash (1987), Kudak (1987) and Kaitira (1987) provide brief summaries of algal research in Fiji, Papua New Guinea, and the Solomon Islands respectively. Habitat Specimens of these genera can be found in a wide variety of habitats including reef-flats, small bays, lagoons, and mangrove areas. Similar habitats usually have characteristic floras, and for particular islands, a given species is usually common in characteristic habitats. On Guam for example, Gracilaria salicornia is common on reef-flats while Polycavernosa tsudae is common in small bays and protected subtidal areas. However, both species occur together in abundance on the reef-flats and in the seagrass beds of Yap proper (Tsuda et al., 1987). However, a species may inhabit several different habitats. For example, a variety of P. tsudae from Saipan is common in Garapan lagoon, a habitat very different from the small bays where another variety (f ,of the same species is found around Guam. The abilities of these ^seaweeds to reproduce vegetatively, in combination with a high degree of phenotypic plasticity, allow populations to become very well adapted to local conditions. Some evidence indicates that there may be distinguishable genetic differences between thalli growing at different depths within particular habitats (Matlock and Romeo, 1981). The work by Womersley and Bailey (1969) provides a summary of the dominant algae found in common habitats of the Solomon Islands and these categorizations may also be applicable to other islands of the tropical Pacific. Trophic biology Seaweeds are primary producers and are exploited by a wide variety of herbivores. On Pacific reefs the intense grazing and selective browsing by herbivorous fishes, primarily siganids, acanthurids, scarids, and pomacentrids, are major factors influencing algal standing crops, community structure, and productivity (Birkeland et al., 1985). Although some tropical / .seaweeds have evolved morphological and chemical defenses against v- herbivory (Paul, 1987), species of the genera Gracilaria, Polycavernosa. and Eucheuma are not so defended and are readily eaten by a variety of reef herbivores, (Nelson and Tsutsui, 1981) many of which can become pests on seaweed farms (Doty, 1987). Herbivorous reef fishes, especially siganids, can constitute a major problem in the establishment and maintenance of seaweed farms on reefs and in lagoons (Doty, 1982; 1987). The strategies employed to reduce losses to herbivores include: selection of sites with reduced access to herbivorous fishes, protection of the seaweed by fences, and dilution of the impact of the fishes by increasing the biomass of the initial seaweed stocks so that herbivores become satiated. The latter strategy can be successful since the roaming, mixed-species schools of herbivorous fishes stay within a home range such that migration from distant areas to the farm site is unlikely. In instances SPC/lnshore Fish. Res./WP.12 Page 4 where these strategies are ineffective, they may have to be supplemented by intense fishing pressure. Reproductive biology Species of the genera Gracilaria. Polycavernosa. and Eucheuma exhibit triphasic patterns of life history. The three phases are: a diploid sporophyte phase, a haploid gameteophyte phase, and a diploid carposporophyte phase which is "parasitic" on the female gametophyte. However, most farmed populations are sterile and reproduce vegetatively (Doty, 1987). It is, therefore, relatively simple to propogate those thalli which show superior rates of growth, which have a greater phycocolloid content, or which produce gels of higher quality. PHYCOCOLLOID INDUSTRY General description of the industry There is a growing international market for phycocolloids. These complex mixtures of polysaccharides extracted from seaweeds form gels at room temperature and are used for a variety of commercial purposes including as emulsifiers and stabilizers in food products, as media for the culture of microbiological organisms, as carriers for pharmaceutical products, and as ingredients in a diverse array of products ranging from ice-cream to shoe polish (Armisen and Galatas, 1987; Stanley, 1987). Markets exist for the dried phycocolloid-bearing seaweeds as well as for the extracts. The production of seaweeds used in the industry comes largely from developing countries in and Latin America, but the production of phycocolloids from these raw materials occurs primarily in the developed nations of Denmark, France, Japan, Norway, Spain, the United Kingdom, and the United States (Food and Agriculture Organization of the United Nations, 1983; Infofish, 1983). Within the region, possibilities exist for establishing both seaweed farms and small-scale phycocolloid extraction facilities. Since the seaweeds can be dried in the sun, stored for long periods and shipped by boat, seaweed mariculture is well suited for small-scale development in remote locations. However, success in developing a seaweed industry depends upon establishing a distribution and marketing structure which will help to stabilize prices and provide incentive to farmers to produce reliable harvests of consistent quality (Food and Agriculture Organization, 1983). Uwate (1987) surveyed potential seaweed buyers in a study for Yap state and reported that the existing markets may be difficult to penetrate except through joint-ventures with existing firms.

Harvesting and culture methods The successful development of regional phycocolloid industries requires the harvest of large quantities of seaweeds. SPC/lnshore Fish. Res./WP.12 Page 5

It is likely that the wild stocks in most countries within the region will be insufficient to meet such demands. Therefore, regional development will rely primarily on cultivation rather than on the harvest of natural stocks. The commercial production of phycocolloid-bearing seaweeds is accomplished either by pond culture or by monofilament-line method on reefs and in lagoonal habitats. Culture of Eucheuma is accomplished by tying thalli at intervals along a monofilament nylon line attached within the sublittoral zone to stakes driven into the substratum (Why, 1985; Doty, 1987). Why (1985) reports that a farm consisting of 300 7- m lines can produce 39 tons of raw Eucheuma per hectare per year. Species of Eucheuma are not cultured in ponds since they generally require areas with considerable water motion. Gracilaria can be cultured either on monofilament lines, as described above for Eucheuma culture, or in shallow (<1 m deep) ponds. Chen (1976) provides a general description of the culture of Gracilaria in ponds in southern Taiwan. Ponds are stocked with 3,000 to 5,000 kg of healthy stock per hectare. Harvests occur every 10 days from June to December. Other species such as milkfish or shrimp are stocked along with the seaweeds to provide additional income. Economics Factors affecting the price for dried seaweeds include the content of impurities such as epiphytes, sand, small shells, and encrusting organisms, the moisture content, and the phycocolloid content. A moisture content of 14 to 18 percent is desirable (Moss and Doty, 1987) and can be achieved by drying the algae under bright sunlight. The price paid to the farmer for suitable dried Eucheuma in the Philippines is $275 to $325 per ton (Moss and Doty, 1987). The quality of the extracts is largely determined by the strength of the gel, determined as grams per square centimeter. Extracts from seaweeds collected within Micronesia have been shown to exhibit gel strengths in the range which render them suitable for use in food-grade agar production (Nelson et al., 1983). Attempts to develop post-harvest treatments to increase the gel strength have met with limited success (Wilkins, 1986). Prices for phycocolloids vary with season, quality, and form of the product. For example, Armisen and Galatas (1987) reported that from 1984 to 1986 the price for food-grade agar imported to Japan in strips or* squares ranged from $10 to $21 per kg, while the average value of these products which were exported ranged from $16 to $45 per kg. Moss and Doty (1987) estimate that the world-average prices will stabilize at $5 to $6 per pound for food-grade agar and at $10 to $12 per pound for bacteriological-grade agar. The price for carrageenan, which depends* on the degree of refinement of the product and sales volume, ranges from $2.50 to $8.00 per pound (Moss and Doty, 1987). In 1983 the estimated world-average price was $3.50 per pound for carrageenan (Moss and Doty, 1987). SPC/Inshore Fish. Res./WP.12 Page 6 Processing and marketing The techniques for producing agar and carrageenan differ, but, commercial plants for either require large volumes of heated water to extract the gels (Armisen and Galatas, 1987; Stanley, 1987) . Moss and Doty (1987) provide detailed descriptions of the extraction procedures for both agar and carrageenan in their feasibility analysis of establishing phycocolloid plants in Hawaii. Plants also must dispose of waste water and solid wastes. In considering the possibility of developing regional facilities for the production of either agar or carrageenan, a number of general considerations come to mind. Production of agar is technologically less complex and requires less of a capital investment, than the production of carrageenan. Also, agar production can be carried out on a small scale, and numerous production facilities have been established. On the other hand, few companies, only 18 world-wide in 1980, are involved with the production of carrageenan (Food and Agriculture Organization of the United Nations, 1983), and approximately 75% of the world production comes from only three companies (Moss and Doty, 1987). Although the opportunities for regional involvement in phycocolloid production seem to be better for agar than for carrageenan, detailed cost-analyses are needed. Among the major considerations for agar production in tropical areas are the costs of cooling and freezing the extracts and the associated economies of scale (Food and Agriculture Organization, 1983).

ASSESSMENT OF STOCKS Survey techniques A number of techniques can be successfully employed to survey natural seaweed stocks. Birkeland (1984) recommends guarding against over-standardization and suggests the use of several independent methods for exploratory surveys. Most such assessments begin with qualitative surveys to document the presence or absence of particular seaweeds at selected locations. Qualitative observations can be effectively accomplished by divers working from small boats by free-swimming observation, towed observation, or spot-check surveys (Kenchington, 1978). Preliminary aerial, photographic surveys can also be useful for broad-scale mapping of zones such as seagrass beds or coral habitats (Hopley, 1978). More detail concerning distributions and abundances of algal resources can be obtained with the use of replicate transects or quadrats, or a combination of both as discussed by Loya (1978). A recent example of a tropical marine algal survey is provided in the work of Mshigeni (1987) for the Seychelles. Standing stocks of marine algae are usually expressed as percent cover and/or biomass per unit area. For example, Ramirez et al. (1981) studied beds of Gracilaria verrucosa in Chile and found that percent cover ranged from 35 to 76% at densities SPC/Inshore Fish. Res./WP.12 Page 7 ranging from 272 to 540 grams dry weight per square meter. Tsuda et al. (1987) found up to 80% percent cover by Gracilaria in natural beds of Yap lagoon. Doty (1973) noted that Eucheuma densities of 50 to 1500 grams per square meter characterize beds which are attractive for wild-crop harvesting, and Dawes (1974) reported that, in Florida, densities of Eucheuma isiforme can reach 2000 grams per square meter. Estimating production Several methods have been used to estimate algal productivity in the field. Thalli can be weighed, marked, allowed to grow and reweighed to determine the percent growth per day (Hoyle, 1978; Nelson and Tsutsui, 1982; Nelson et al., 1982). This method is particularly effective for farmed algae. Also, laboratory measurements of production, usually in terms of the rates of 02 production (James, 1982; Morrissey, 1985; Nelson, 1985; Nelson and Siegrist, 1987), can be used in conjunction with data on standing stocks and environmental factors (photon flux density, temperature, etc.) to estimate rates of production in the natural environment (Pendleton, 1983; Carpenter, 1985; Garrigue, 1985). Yield per unit area Growth rates of Eucheuma thalli generally are between 1 and 5% per day (Parker, 1974; Doty, 1987), and successful Eucheuma farms produce 15 to 30 dry tons per hectare per year (Moss and Doty, 1987). Trials at Kirabati have demonstrated production within the range of 26 to 39 dry kg per hectare per year (Why, 1985) . Growth rates of Gracilaria and Polycavernosa thalli range between 2 and 7 percent per day in shallow tropical waters (Nelson et al., 1980; Nelson et al., 1982; Nelson and Tsutsui, 1982) . In Taiwan, production of Gracilaria in ponds generally ranges from 10,000 to 20,000 dry kg per hectare per year (Chen, 1976; Chueh and Chen, 1982) with a drying ratio of 1:7 (Chen, 1976) . Habitat degradation/destruction Natural beds of seaweeds in accessible areas can be easily overharvested as has been documented in the Philippines for Eucheuma (Parker, 1974) resulting in declining annual yields. Also, Santelices (1987) points out that careless harvesting of wild stocks can have serious long-term effects and that cutting the thalli rather than scraping the substratum will result in more rapid regrowth in harvested areas. Removal of the creeping portions of the thalli from the substratum during harvest allows the competitive invasion of other algal species. Economic seaweeds have been shown to grow well in areas where they do not occur naturally. However, the introduction of exotic marine macrophytes for culture may be of consequence to the indigenous flora and fauna, and consideration of the SPC/Inshore Fish. Res./WP.12 Page 8 potential environmental impacts of exotic species should be considered prior to introduction. Eldredge (1987) provides a general discussion of the introductions of marine organisms to coral reef habitats and includes a section on introduced seaweeds. The introduction of Eucheuma to Hawaii and Fanning Atoll have also resulted in the inadvertent introduction of epiphytic algae. Also, the intentionally introduced Eucheuma began to spread in Kanehoe Bay, Hawaii (Russell; 1983) with associated decline of fishes and invertebrates in the areas of heavy infestation. However, efforts to control the introduced alga were successful, and the spread of Eucheuma from farm sites has not been a problem in other areas where it has been introduced. REGULATION, MANAGEMENT AND CONSERVATION Economic seaweeds are renewable resources and, as such, need to be conserved for future generations. The development of regional seaweed industries will require regulation by local governments or traditional policy-formulating bodies in regard to issues such as reef ownership and the introduction of exotic species. Parker (1974) points out that, for numerous reasons, conservation measures for Eucheuma were difficult to establish in the Philippines, but that the development of seaweed cultivation itself serves as a conservation measure. Santileces (1987) reports that there are regulations established regarding the harvest of Gracilaria in Chile, but the nature of the regulations was not specified. Among the first steps toward management of these resources for many islands of the region is to identify the local species of economic potential and to obtain estimates of their abundance. Once potentially economic species have been identified, steps can be taken to develop and manage these resources. SPC/lnshore Fish. Res./WP/12 Page 9

LITERATURE

Armisen, R. and R. Galatas. 1987. Production, properties and uses of agar. pages 1-57 in D. J. McHugh, ed. Production and utilization of products from commercial seaweeds. Food and Agriculture Organization of the United Nations, Rome. Birkeland, C. 1984. A contrast in methodologies between surveying and testing, pages 11-26 in Comparing coral reef survey methods. Unesco Reports in Marine Science 21. Birkeland, C, S. G. Nelson, S. Wilkins, and P. Gates. 1985. Effects of grazing by herbivorous fishes on coral reef community metabolism. Proceedings of the Fifth International Coral Reef Congress, Tahiti Vol. 4:47-51. Carpenter, R. C. 1985. Relationships between primary production and irradiance in coral reef algal communities. Limnology and Oceanography 30:784-793. Chapman, V. J. 1971. The marine algae of Fiji. Revue Alogologique N.S. 10:164-171. Chen, T. P. 1976. Aquaculture practices in Taiwan. Fishing News Books Ltd., Farnham, Surrey, England. Chueh, C. T. and C. C. Chen. 1982. Seaweed economics in Taiwan. pages 9-16 in R. T. Tsuda and Y. M. Chiang, eds. Proceedings of Republic of China—United States cooperative science seminar on cultivation and utilization of economic algae. University of Guam Marine Laboratory, Mangilao, Guam. Dawes, C. J. 1974. On the mariculture of the Florida seaweed, Eucheuma isiforme. Florida Sea Grant Program Report No. 5. 10 p. Doty, M. S. 1973. Farming the red seaweed, Eucheuma, for carrageenans. Micronesica 9:59-73. Doty, M. S. 1982. The diversified farming of coral reefs. University of Hawaii HaBold L. Lyon Arboretum Lecture Number 11. University of Hawaii Press, Honolulu, Hawaii. Doty, M. S. 1985. Eucheuma alvarezii. sp. nov. (Gigartinales, Rhodophyta) from Malaysia. pages 36-54 .in I. A. Abbott and J. Norris, eds. Taxonomy of economic seaweeds with reference to some Pacific and Caribbean species. California Sea Grant College Report no. T-CSGCP-011. (available from the University of California, A-03, La Jolla, California 92093). SPC/Inshore Fish. Res. WP.12 Page 10

Doty, M. S. 1987. The production of Eucheuxna. pages 49-122 in M. S. Doty, J. F. Caddy, and B. Santelices, eds. Case studies of seven commercial seaweed resources. FAO Fisheries Technical Paper 281. Food and Agriculture Organization of the United Nations, Rome. Doty, M. S. and J. N. Norris. 1985. Eucheuxna species (Solieriaceae, Rhodophyta) that are major sources of Carrageenan. pages 47-62 in I. A. Abbott and J. Norris, eds. Taxonomy of economic seaweeds with reference to some Pacific and Caribbean species. California Sea Grant College Report no. T-CSGCP-011. (available from the University of California, A-03, La Jolla, California 92093). Eldredge, L. G. 1987. Coral reef alien species, pages 215-228 in B. Salvat, ed. Human Impacts on Coral Reefs: Facts and Recommendations. Antenne Museum E.P.H.E., French Polynesia. Food and Agriculture Organization. 1983. ADB/FAO Second Fish Market Study. Vol. 6. The world seaweed industry and trade: Developing Asian producers and prospects for greater participation. Asian Development Bank and the Food and Agriculture Organization of the United Nations, South China Sea Fisheries Development and Coordinating Programme (SCSP), Marketing Information and Advisory Service for Fish Products in the Asian/Pacific Region (INFOFISH). Fredrique, S. and J. N. Norris. 1985. Morphological studies on some tropical species of Gracilaria Grev. (Gracilariaceae, ' Rhodophyta): Taxonomic concepts based on reproductive morphology, pages 137-155 in I. A. Abbott and J. Norris, eds. Taxonomy of economic seaweeds with reference to some Pacific and Caribbean species. California Sea Grant College Report no. T-CSGCP-011. (available from the University of California, A-03, La Jolla, California 92093). Furtado, J. I. and C. Y. Wereko-Brobby, eds. 1987. Tropical Marine Algal Resources of the Asia-Pacific Region: A Status Report. CSC Technical Publication Series No. 181. Commonwealth Science Council, London. Garrigue, C. 1985. Repartition et production organique et minerale de macrophytes benthiques du lagon de nouvelle- caledonne. Doctoral Dissertation, Academie de Montpellier. 270 p. Garrigue, C. and R. T. Tsuda. in press. Bibliography of marine benthic algae from New Caledonia. Micronesica. Hopley, D. 1978. Aerial photography and other remote sensing techniques, pages 23-44 in D. R. Stoddart and R. E. Johannes, eds. Coral reefs: research methods. United Nations Educational, Scientific and Cultural Organization, Paris. SPC/Inshore Fish. Res./WP.12 Page 11

Hoyle, M. D. 1978. Reproductive phenology and growth rates in two species of Gracilaria from Hawaii. J. Exp. Mar. Biol. Ecol. 35:273-283.

Infofish. 1983. Seaweeds—products and markets. Infofish Marketing Digest No. 4/83:23-26.

James, S. 1982. Photosynthesis and respiration of two species of red algae, Gracilaria arcuata and Gracilaria edulis from Guam. M. S. Thesis in Biology, University of Guam. 22 p.

Kaitira, B. 1987. Marine algal resources of the Solomon Islands, pages 101-104 in J. I. Furtado and C. Y. Wereko- Brobby, eds. Tropical marine algal resources of the Asia- Pacific region: a status report. Commonwealth Science Council Technical Report Series No. 181. Kenchington, R. A. 1978. Visual surveys of large areas of coral reefs, pages 149-162 in D. R. Stoddart and R. E. Johannes, eds. Coral reefs: research methods. United Nations Educational, Scientific and Cultural Organization, Paris.

Kudak, M. M. 1987. Marine algal resources of Papua New Guinea. pages 81-89 in J. I. Furtado and C. Y. Wereko-Brobby, eds. Tropical marine algal resources of the Asia-Pacific region: a status report. Commonwealth Science Council Technical Report Series No. 181.

Loya, Y. 1978. Plotless and transect methods. pages 197-217 in D. R. Stoddart and R. E. Johannes, eds. Coral reefs: research methods. United Nations Educational, Scientific and Cultural Organization, Paris.

Matlock, D. B. and C. Romeo. 1981. Interspecific variability within the genus Gracilaria (Rhodophyta) on Guam. Proceedings of the Fourth International Coral Reef Symposium, Manila, Vol. 2:415-417.

Meneses, I. and I. A. Abbott. in press. Gracilaria and Polycavernosa (Rhodophyta) from Micronesia. Micronesica. Mshigeni, K. E. 1987. Marine algal resources of Seychelles: A survey of the species occurring on the island and an assessment of their potential for agriculture, commerce, phycocolloid industry and other uses. CSC Technical Publication Series No. 196. Commonwealth Science Council, London.

Morrissey, J. 1985. Primary productivity of coral reef benthic macroalgae. Proceedings of the Fifth Coral Reef Congress, Tahiti, vol. 5:77-82. SPC/Inshore Fish. Res./WP.12 Page 12

Moss, J. R. and M. S. Doty. 1987. Establishing a seaweed I industry in Hawaii: and initial assessment. Aquaculture Development Program of the Hawaii State Department of Land • and Natural Resources, Honolulu, Hawaii. 73 p. I Nelson, S. G. 1985. Immediate enhancement of photosynthesis by marine macrophytes in response to ammonia enrichment. I Proceedings of the Fifth International Coral Reef Congress, ' Tahiti, Vol. 5:65-70. Nelson, S. G. , D. B. Matlock, and J. P. Villagomez. 1982. § Distribution and growth of the agarophyte Gracilaria lichenoides (Rhodophyta) in Saipan Lagoon. Sea Grant „ Quarterly 4(1):1-6. | Nelson, S. G. and A. W. Siegrist. 1987. Comparison of mathematical formulations for simulating the photosynthesis- light relations of tropical marine macrophytes. Bulletin of Marine Science 41:617-622. I Nelson, S. G. and R. N. Tsutsui. 1981. Browsing by herbivorous reef-fishes on the agarophyte Gracilaria I edulis at Guam, Mariana Islands. Proceedings of the Fourth International Coral Reef Symposium, Manila, I Vol. 1:503-506. • Nelson, S. G., R. N. Tsutsui, and B. R. Best. 1980. Preliminary evaluation of the mariculture potential of Gracilaria I (Rhodophyta) in Micronesia: Growth and ammonia uptake, p. 72-79. In: I. A. Abbott and M. S. Foster (eds.), Seaweeds ^ of the Warm Pacific. California Sea Grant Program, I University of California, La Jolla. Nelson, S. G., S. S. Yang, C. Y. Wang, and Y. M. Chiang. 1983. Yield and quality of agar from species of Gracilaria (Rhodophyta) collected from Taiwan and Micronesia. Botanica Marina 26:361-366. Parker, H. S. 1974. The culture of the red algal genus Eucheuma in the Philippines. Aquaculture 3:425-439. Paul, V. J. 1987. Feeding deterrent effects of algal natural I products. Bulletin of Marine Science 41:514-522. Payri, C. E. and A. Meinesz. 1985. Algae. Proceedings of the Fifth International Coral Reef Congress, Tahiti 1:498-516. I Pendleton, D. E. 1983. Potential impact of a proposed stack gas sulffur scrubber on Gracilaria arcuata (Rhodophyta) . M. S. 1 Thesis in Biology, University of Guam. 36 p. Prakash, J. 1987. The marine algae resources of Fiji, pages 2 3-29 in J. I. Furtado and C. Y. Wereko-Brobby, eds. Tropical marine algal resources of the Asia-Pacific region: 1 SPC/Inshore Fish. Res./WP.12 Page 13

a status report. Commonwealth Science Council Technical Report Series No. 181. Ramirez, C, P. Rivera, E. Stegmaier, and D. Contreras. 1981. Prospeccion de Gracilaria verrucosa en la Bayia de Corral y Ensedada de San Juan (Valdivia, Chile). Rev. Biol Mar. Inst. Oceanol. Univ. Valparaiso 17(3):389-404. Russell, D. J. 1983. Ecology of the imported red seaweed Eucheuma striatum Schmitz on Coconut Island, Oahu, Hawaii. Pacific Science 37:87-107. Santelices, B. 1987. The wild harvest and culture of the economically important species of Gelidium in Chile, pages 165-192 in M. S. Doty, J. F. Caddy, and B. Santelices, eds. Case studies of seven commercial seaweed resources. Food and Agriculture Organization Fisheries Technical Paper 281. Stanley, N. 1987. Production, properties and uses of carrageenan. pages 116 to 146 in D. J. McHugh, ed. Production and utilization of products from commercial seaweeds. Food and Agriculture Organization of the United Nations, Rome. Tsuda, R. T. 1981. Bibliography of marine benthic algae of Micronesia: Addendum. Micronesica 17:213-218. Tsuda, R. T. 1982. Seasonality in Micronesian seaweed populations and their biogeography as affecting wild crop potential, pages 2 3-32 in R. T. Tsuda and Y. M. Chiang, eds. Proceedings of Republic of China-United States Cooperative Science Seminar on Cultivation and Utilization of Economic Algae. University of Guam Marine Laboratory, Mangilao, Guam. Tsuda, R. T. 1985. Gracilaria from Micronesia: Key, list and distribution of the species. pages 91-92. in I. A. Abbott and J. Norris, eds. Taxonomy of economic seaweeds with reference to some Pacific and Caribbean species. California Sea Grant College Report no. T-CSGCP-011. (available from the University of California, A-03, La Jolla, California 92093). Tsuda, R. T., S. G. Nelson, V*. J. Paul, and K. L. Van Alstyne. 1987. Survey of potentially important economic seaweeds in Yap Lagoon, Micronesia. Submitted to the Marine Resources Management Division, Yap State Department of Resources and Development, Colonia, Yap, Federated States of Micronesia 96943. 15 p. Tsuda, R. T. and F. 0. Wray. 1977. Bibliography of marine benthic algae in Micronesia. Micronesica 13:85-12 0. SPC/Inshore Fish. Res./WP.12 Page 14

Uwate, K. R. 1987. A survey of seaweed buyers. Unpublished report. Available from the Marine Resources Management Division, Yap State Department of Resources and Development. 11 p. Why, S. 1985. Eucheuma in Kirabati. South Pacific Commission Seventeenth Regional Technical Meeting on Fisheries, Working Paper 19. 7 p. Wilkins, S. dec. 1986. Effects of post-harvest holding conditions on the quality of agar extracted from two species of Gracilaria (Rhodophyta) from Guam. M. S. Thesis in Biology, University of Guam. 29 p. Womersley, H. B. S. and A. Bailey. 1969. The marine algae of the Solomon Islands and their place in a biotic reef. Philosophical Transactions of the Royal Society of London B. Biological Sciences 255:433-442. Womersley, H. B. S. and A. Bailey. 1970. Marine algae of the Solomon Islands. Philosophical Transactions of the Royal Society of London, B. Biological Sciences 259:257-352. Xia, B. M. and I. A. Abbott. 1985. The genus Polycavernosa Chang et Xia (Gracilariaceae, Rhodophyta): A comparison with Gracilaria Grev., and a key to the species, pages 157- 162 in I. A. Abbott and J. N. Norris, eds. Taxonomy of economic seaweeds with reference to some Pacific and Caribbean species. California Sea Grant College Program Report no. T-CSGCP-011.

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