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Economic aspects of Gracilaria culture in Taiwan
1
Aquaculture, 8 (1976) l-7 0 Elsevier Scientific Publishing Company, Amsterdam - Printed in The Netherlands
ECONOMIC ASPECTS OF GRACZARIA
CULTURE IN TAIWAN
YUhrG C. SHANG Hawaii Institute of Marine Biology, University of Hawaii, Honolulu, Hawaii 96822 (Received June 2nd, 1975; revised @gust
(U.S.A.)
8th, 1975)
ABSTRACT Shang, Y.C., 1976. Economic aspects of Gracilaria culture in Taiwan. Aquaculture, l-7.
8:
The cultivation of Gracilaria is described, costs and returns of the operation are analyzed, and the market demand is evaluated. Gracilaria culture is a labor-intensive operation. However, annual productivity and profit are high. The increasing demand and rising price of raw Gracilaria, and agar derived from it, are likely to encourage Gracilaria cultivation not only in Taiwan but also in other developing countries with sites suitable for its cultivation. INTRODUCTION
Plants of the red algal genus Gracilaria are used in some Asian countries as a human dietary item and as a food source in pondfish culture. However, of major and growing importance is the use of Gracilariu as a raw material for the manufacture of agar. Agar is produced from various genera of red algae (e.g. Gelidium, Gruciluriu, and Pterocludiu) when the plants are boiled, after being dried, and the resulting liquid is cooled. Agar has a number of uses (Mathieson, 1975), including the preservation of canned meats and the preparation of sizing for fabrics. It is used as an ingredient of waterproof paper, cloth and glue, as a cleaning medium, as a clarifying agent in the manufacturing of wines, beers and coffee, and as a covering for pharmaceutical capsules. Culture of Gracilariu in Taiwan started in 1962. However, the industry lacked growth until very recently. Declining natural production because of overharvesting, rising prices owing to growing demand, and improvements in culture techniques have resulted in a rapid expansion of Graciluriu culture in recent years. The acreage of Gruciluriu under cultivation in Taiwan increased from about 100 ha in 1971 to about 250 ha in 1973. The total production in 1973 was about 2 500 t (metric tons) of dry Grucilariu. Four species of Grucilariu of economic importance are recognized in Taiwan: G. gigas, G. confervoides, G. lichenoides and G. compressa. Of these, G. confervoides is the most extensively cultured species because of its adaptability to a wide range of environmental conditions, the high rate at which it
2
can be cropped and the high gel strength of the dried product. Taiwan is the only place in the world where this seaweed is cultured in ponds. This paper describes the procedures of cultivation, analyzes the costs and returns of the operation, and evaluates the market potential. CULTIVATION
The regenerative properties of Gruciluriu have been utilized as a means of increasing the natural yield of the plant. Gracifuriu reproduces both vegetatively and by sporulating. Gametophytes of Gruciluriu are heterothallic. The male thalli produce spermatangia. The eggs produced by the female gametophyte are fertilized and develop into carposporophytes, which produce carpospores. The carpospores develop into tetrasporophytes. Tetraspores are produced from the tetrasporophytes and germinate into male and female gametophytes (Chen, 1975). A single Gruciluriu plant produces over 60 000 tetraspores and more than 40 000 carpospores (Mathieson, 1975). Gruciluriu grows most rapidly in waters of about 25°/oo salinity, and at temperatures of 20-25 “C (Lin, 1974). The plants begin to die when salinity exceeds 35°/oo. Most of the culture ponds in Taiwan are located in the southern part of the island where high temperatures prevail. The following should be taken into consideration for the selection of a pond site (Chen, 1975): (a) Fresh water should be available for dilution of the sea water where increases in salinity can occur owing to evaporation. (b) The area should not be exposed to strong winds, which can move the plants from their fixed locations. (c) There should be sufficient tidal differences to facilitate exchange of water. (d) The bottom should be sandy loam. (e) The pH of the water should be between 6 and 9, with an optimum of 8.2-8.7. Tidal land and ponds formerly used for milkfish production are used for Gruciluriu culture in Taiwan. The ponds, usually rectangular, are about 1 ha in area. The depth of water in the ponds generally is 20-30 cm during the months of March to June, and 60-80 cm after June, the added volume being conducive to counteract seasonal increases in water temperature. The cuttings or torn sections of the plant are used as planting stock. About 5 000 kg of the fragmented plants are planted per hectare in April, at the beginning of the growing season. They are strewn evenly on the bottom and are held in place with upright bamboo sticks fixed to the bottom. Alternatively, the plants may be covered with old fish nets to prevent them from drifting. The best planting time is early or late in the day, and in cloudy weather. Water in the ponds is exchanged every 2-3 days after planting to provide nutrients for growth and to maintain an appropriate salinity. Unwanted weed growth must be removed at least three times a year. Otherwise, the weeds cover the plants and reduce their growth. Milkfish and Tilupia are usually
3
stocked in the same pond, not for profit, but to browse on and control the green and blue-green algae that tend to shade out the Gracilaria. The stocking rate is about 300-400 fish/ha. These fishes need to be removed when the algae are consumed; otherwise they will also consume the Gracilaria. Fertilization of the ponds is necessary to accelerate the growth of the plants. Either organic (urea) or inorganic fertilizer (fermented pig manure) is used. The harvesting period ranges from June to November. The crop is gathered every 10 days by hand or by the use of scoop nets. The harvested plants are washed and sun-dried on bamboo screens or plastic sheets. About 7 kg of plants yield 1 kg of dry seaweed. Gracilaria stops growing from December to March owing to the cold weather in Taiwan. The plants do not tolerate temperatures below 8°C. COSTS AND RETURNS
There are two types of Gracilaria culture in Taiwan - monoculture and polyculture. Gracilaria culture requires few facilities and equipment (Table I). Therefore the initial capital costs are relatively small, comnared with those of other types of aquaculture, and they are the same for the two types of operation. Costs of production and profit rates, however, differ for monoculture and polyculture operations. Annual operating costs and returns for the two types of culture, based on field surveys (Taiwan Fisheries Bureau, 1973; Cheng, 1974), are estimated separately. Monoculture Labor and seed are the most important operating costs. They account for about 53 and 18%, respectively, of total annual expenses (Table II). Labor costs include seeding, weeding, harvesting and drying, and management. Harvesting and drying are more labor consuming than other activities. They require about 100 working days per ha per Sear, while weeding and seeding require 30 and 2 days, respectively. Annual yield per hectare is 7-12 t of dry Gracilaria. It varies with water temperature, management and planting density. On the average, 10 t of dry Grucilaria can be harvested per hectare, starting with 5 000 kg of seeding stock. Yhis yield provides an income of $2 750, which is about twice the annual operating cost. Annual profit can be as high as $1 368 and the initial investment can be paid back within 2 years. Polyculture Grass shrimp (translated directly from its Chinese name) (Penaeus monodon) and crabs (Scylla serrata) are reared together with Gracilaria in the same pond to provide additional income. The planting rate of Gracilaria in this case is
4
lower (4 000 kg/ha), compared with that for monoculture (5 000 kg/ha). The direct production cost of Gradaria accounts for only about 11% of the total annual operating expenses, while grass shrimp and crab account for about 32 and 38%, respectively (Table III). Again, labor is the most important direct cost for Gradaria, while procurement of young shrimps and crabs and feed requirements are the major cost items for shrimp and crab rearing. TABLE I Estimated initial capital cost per hectare in the culture of Gracilaria (Taiwan)
Cost ($1 Pond construction Bamboo raft Well, motor and pump Storage Nets Baskets
625 100 1200 500 12 4
Total
2 441
TABLE II Costs and returns of Gracilaria monoculture
(per hectare)
Quantity
Amount ($)
Percentage
costs Labor Seeding Weeding Harvesting and drying Management
2 days 30 days 100 days 6 months
5 75 275 375
0.4 5.4 19.9 27.1
730
52.8
5 000 ‘kg 4 000 kg
250 100 134 125 43
18.1 7.2 9.7 9.0 3.1
10 t (dry)
2 750
Subtotal Seed stock Fertilizer Depreciation (derived from Table I) Tax and maintenanoe Lease Total cost Revenue Profit Rate of return on initial investment (profit divided by initial investment) Profit per dollar of operating cost (profit divided by total operating cost)
1 382
1 368 56% 0.99
Average annual production of Gradaria is slightly less (9 t/ha) compared to production in monoculture (10 t/ha). However, there is an additional production of grass shrimp and crab of about 6.3 t/ha. The total value of annual production is about $4 438, yielding a profit of $2 381/ha. The initial investment can be paid back virtually at the end of the first year of operation. Annual profit of Grucihia polyculture is about 1.7 times higher than that of monoculture, while annual operating cost is about 4.4 times higher. Therefore, the profit rate per dollar of operating cost is higher for monoculture ($0.99) than for polyculture ($0.39)., Polyculture tends to increase the efficiency of land use when land resources are more scarce than capital. Where capital is more scarce than land, monoculture seems more appropriate. MARKET
DEMAND
About 31% of the total Gruciluria production in Taiwan in 1973 was consumed fresh as food. Another 31% was exported as raw material for manufacturing agar. The remaining 38% was processed into agar in Taiwan for domestic and foreign markets. Japan is the major agar-consuming country. Domestic demand for agar in Japan increased from 2 182 t in 1968 to 2 429 t in 1973, with an annual increase of about 2.3% (Agar Producers’ Association, 1974). Japan has been the major agar-importing country due to its declining natural production of the raw materials. In 1972, Japan imported 720 t of agar (an increase of about 43% annually between 1968 and 1972), followed by Britain (654 t), West Germany (626 t), and the United States (536 t). Portugal is the most important agar-exporting country (600-700 t annually), followed by Denmark (about 600 t), Spain and Morocco (about 300 t each), and Korea and Argentina (100-200 t each). Prices of agar in the major importing countries increased significantly during recent years. For instance, the price of agar in Japan increased 56-105% between 1971 and 1973, depending on types of product (powder, strip). Japan has been the most important importing country not only for manufactured agar but also for raw Gracilaria for processing into agar. In 1973, Japan imported about 8 000 t of raw Gradaria, about 47% more than in 1972. The Philippines, Brazil, Taiwan, Chile and Argentina are the major exporters of raw Gracilaria. The average import price of raw Gradariu in Japan was about $500/t in 1973, an increase of about 25% over 1972. When production costs of about $135/t are compared with the average import price in Japan, the culture and export of raw Grucilariu to Japan appears to be a profitable business for Taiwanese Grucilariu growers. The profit is expected to be higher if the raw material is processed into agar for export. CONCLUSIONS
Grucilaria culture in ponds is a labor-intensive operation. Cost of labor ac-
TABLE III Costs and returns of Gracilaria polyculture (per hectare) Quantity
Direct cost Gracilaria Labor Seed stock Fertilizer
132 days 4 000 kg 4 000 kg
Percentage
330 200 100
5.4 3.3 1.7
630
10.4
1 500 350 100
24.8 5.8 1.7
1950
32.3
1 000 1 250 50
16.5 20.6 0.8
2 300
37.9
750 134 250 43
12.4 2.2 4.1 0.7
Subtotal
1 177
19.4
Total cost
6 057
Subtotal Grass shrimp FrY Feed Labor
40 000 individuals
Subtotal Crab Fry Feed Labor
10 000 individuals
Subtotal Indirect cost Management Depreciation Tax and maintenance Lease
Revenues Gracilaria Grass shrimp Crab
12 months
9.0 t (dry) 4.8 t* 1.5 t*
Total revenue
Profit
2 475 2 400 3 563 a 438
2 381
Rate of return on initial investment Profitper
Amount ($)
dollar of operating cost
*Survival rate is 60%.
98% 0.39
29.3
28.4 42.2
7
counts for over 50% of total operating expenses. However, Gruciluriu is a fast-growing seaweed. Annual production rates of 10 t/ha (dry weight) can be attained. In addition, Gruciluria culture requires lower initial operating expenditure than many types of aquaculture. Annual profit can reach $1 399 -$2 413/ha. By comparison, profits from milkfish culture are about $250-500/ha. It is not surprising that many milkfish ponds in Taiwan are being converted to Gruduriu culture. Owing to relatively low labor costs in Taiwan, it is likely that Taiwan’s share in supplying the growing world market for Grucilariu and agar will increase, if production can be expanded. The increasing demand for Gruciluriu and agar and the over-harvesting of natural stocks have resulted in a rising price in the world market. These circumstances likely will encourage the culture of Gruciluriu not only in Taiwan, but also in other developing countries with suitable sites for its cultivation. ACKNOWLEDGEMENT
The author expresses his thanks to Dr John E. Bardach for his helpful ments on the preparation of the manuscript.
com-
REFERENCES Agar Producers’ Association, 1974. Agar Intelligence. Tokyo, February, (in Japanese). Chen, T.P., 1975. Culture of Gracilaria. Taiwan Fisheries Consultant, Inc., Taipei, unpublished manuscript. Cheng, C.C., 1974. Gracilaria Culture and Agar Processing Industry in Taiwan. Joint Comm. Rural Reconstr., Taipei, 23 pp. (in Chinese). Lin, M.N., 1974. Culture of Gracilaria. Fish. Res. Inst. Keelung, 8 pp. (in Chinese). Mathieson, A.C., 1975. Seaweed aquaculture. Mar. Fish. Rev. Nat1 Mar. Fish. Serv., U.S. Dep. Commer., Seattle, Wash., 37 (1) 2-14. Taiwan Fisheries Bureau, 1973. Survey of Production Costs of Fisheries in Taiwan. Taipei, 86 pp. (in Chinese).
Aquaculture, 8 (1976) l-7 0 Elsevier Scientific Publishing Company, Amsterdam - Printed in The Netherlands
ECONOMIC ASPECTS OF GRACZARIA
CULTURE IN TAIWAN
YUhrG C. SHANG Hawaii Institute of Marine Biology, University of Hawaii, Honolulu, Hawaii 96822 (Received June 2nd, 1975; revised @gust
(U.S.A.)
8th, 1975)
ABSTRACT Shang, Y.C., 1976. Economic aspects of Gracilaria culture in Taiwan. Aquaculture, l-7.
8:
The cultivation of Gracilaria is described, costs and returns of the operation are analyzed, and the market demand is evaluated. Gracilaria culture is a labor-intensive operation. However, annual productivity and profit are high. The increasing demand and rising price of raw Gracilaria, and agar derived from it, are likely to encourage Gracilaria cultivation not only in Taiwan but also in other developing countries with sites suitable for its cultivation. INTRODUCTION
Plants of the red algal genus Gracilaria are used in some Asian countries as a human dietary item and as a food source in pondfish culture. However, of major and growing importance is the use of Gracilariu as a raw material for the manufacture of agar. Agar is produced from various genera of red algae (e.g. Gelidium, Gruciluriu, and Pterocludiu) when the plants are boiled, after being dried, and the resulting liquid is cooled. Agar has a number of uses (Mathieson, 1975), including the preservation of canned meats and the preparation of sizing for fabrics. It is used as an ingredient of waterproof paper, cloth and glue, as a cleaning medium, as a clarifying agent in the manufacturing of wines, beers and coffee, and as a covering for pharmaceutical capsules. Culture of Gracilariu in Taiwan started in 1962. However, the industry lacked growth until very recently. Declining natural production because of overharvesting, rising prices owing to growing demand, and improvements in culture techniques have resulted in a rapid expansion of Graciluriu culture in recent years. The acreage of Gruciluriu under cultivation in Taiwan increased from about 100 ha in 1971 to about 250 ha in 1973. The total production in 1973 was about 2 500 t (metric tons) of dry Grucilariu. Four species of Grucilariu of economic importance are recognized in Taiwan: G. gigas, G. confervoides, G. lichenoides and G. compressa. Of these, G. confervoides is the most extensively cultured species because of its adaptability to a wide range of environmental conditions, the high rate at which it
2
can be cropped and the high gel strength of the dried product. Taiwan is the only place in the world where this seaweed is cultured in ponds. This paper describes the procedures of cultivation, analyzes the costs and returns of the operation, and evaluates the market potential. CULTIVATION
The regenerative properties of Gruciluriu have been utilized as a means of increasing the natural yield of the plant. Gracifuriu reproduces both vegetatively and by sporulating. Gametophytes of Gruciluriu are heterothallic. The male thalli produce spermatangia. The eggs produced by the female gametophyte are fertilized and develop into carposporophytes, which produce carpospores. The carpospores develop into tetrasporophytes. Tetraspores are produced from the tetrasporophytes and germinate into male and female gametophytes (Chen, 1975). A single Gruciluriu plant produces over 60 000 tetraspores and more than 40 000 carpospores (Mathieson, 1975). Gruciluriu grows most rapidly in waters of about 25°/oo salinity, and at temperatures of 20-25 “C (Lin, 1974). The plants begin to die when salinity exceeds 35°/oo. Most of the culture ponds in Taiwan are located in the southern part of the island where high temperatures prevail. The following should be taken into consideration for the selection of a pond site (Chen, 1975): (a) Fresh water should be available for dilution of the sea water where increases in salinity can occur owing to evaporation. (b) The area should not be exposed to strong winds, which can move the plants from their fixed locations. (c) There should be sufficient tidal differences to facilitate exchange of water. (d) The bottom should be sandy loam. (e) The pH of the water should be between 6 and 9, with an optimum of 8.2-8.7. Tidal land and ponds formerly used for milkfish production are used for Gruciluriu culture in Taiwan. The ponds, usually rectangular, are about 1 ha in area. The depth of water in the ponds generally is 20-30 cm during the months of March to June, and 60-80 cm after June, the added volume being conducive to counteract seasonal increases in water temperature. The cuttings or torn sections of the plant are used as planting stock. About 5 000 kg of the fragmented plants are planted per hectare in April, at the beginning of the growing season. They are strewn evenly on the bottom and are held in place with upright bamboo sticks fixed to the bottom. Alternatively, the plants may be covered with old fish nets to prevent them from drifting. The best planting time is early or late in the day, and in cloudy weather. Water in the ponds is exchanged every 2-3 days after planting to provide nutrients for growth and to maintain an appropriate salinity. Unwanted weed growth must be removed at least three times a year. Otherwise, the weeds cover the plants and reduce their growth. Milkfish and Tilupia are usually
3
stocked in the same pond, not for profit, but to browse on and control the green and blue-green algae that tend to shade out the Gracilaria. The stocking rate is about 300-400 fish/ha. These fishes need to be removed when the algae are consumed; otherwise they will also consume the Gracilaria. Fertilization of the ponds is necessary to accelerate the growth of the plants. Either organic (urea) or inorganic fertilizer (fermented pig manure) is used. The harvesting period ranges from June to November. The crop is gathered every 10 days by hand or by the use of scoop nets. The harvested plants are washed and sun-dried on bamboo screens or plastic sheets. About 7 kg of plants yield 1 kg of dry seaweed. Gracilaria stops growing from December to March owing to the cold weather in Taiwan. The plants do not tolerate temperatures below 8°C. COSTS AND RETURNS
There are two types of Gracilaria culture in Taiwan - monoculture and polyculture. Gracilaria culture requires few facilities and equipment (Table I). Therefore the initial capital costs are relatively small, comnared with those of other types of aquaculture, and they are the same for the two types of operation. Costs of production and profit rates, however, differ for monoculture and polyculture operations. Annual operating costs and returns for the two types of culture, based on field surveys (Taiwan Fisheries Bureau, 1973; Cheng, 1974), are estimated separately. Monoculture Labor and seed are the most important operating costs. They account for about 53 and 18%, respectively, of total annual expenses (Table II). Labor costs include seeding, weeding, harvesting and drying, and management. Harvesting and drying are more labor consuming than other activities. They require about 100 working days per ha per Sear, while weeding and seeding require 30 and 2 days, respectively. Annual yield per hectare is 7-12 t of dry Gracilaria. It varies with water temperature, management and planting density. On the average, 10 t of dry Grucilaria can be harvested per hectare, starting with 5 000 kg of seeding stock. Yhis yield provides an income of $2 750, which is about twice the annual operating cost. Annual profit can be as high as $1 368 and the initial investment can be paid back within 2 years. Polyculture Grass shrimp (translated directly from its Chinese name) (Penaeus monodon) and crabs (Scylla serrata) are reared together with Gracilaria in the same pond to provide additional income. The planting rate of Gracilaria in this case is
4
lower (4 000 kg/ha), compared with that for monoculture (5 000 kg/ha). The direct production cost of Gradaria accounts for only about 11% of the total annual operating expenses, while grass shrimp and crab account for about 32 and 38%, respectively (Table III). Again, labor is the most important direct cost for Gradaria, while procurement of young shrimps and crabs and feed requirements are the major cost items for shrimp and crab rearing. TABLE I Estimated initial capital cost per hectare in the culture of Gracilaria (Taiwan)
Cost ($1 Pond construction Bamboo raft Well, motor and pump Storage Nets Baskets
625 100 1200 500 12 4
Total
2 441
TABLE II Costs and returns of Gracilaria monoculture
(per hectare)
Quantity
Amount ($)
Percentage
costs Labor Seeding Weeding Harvesting and drying Management
2 days 30 days 100 days 6 months
5 75 275 375
0.4 5.4 19.9 27.1
730
52.8
5 000 ‘kg 4 000 kg
250 100 134 125 43
18.1 7.2 9.7 9.0 3.1
10 t (dry)
2 750
Subtotal Seed stock Fertilizer Depreciation (derived from Table I) Tax and maintenanoe Lease Total cost Revenue Profit Rate of return on initial investment (profit divided by initial investment) Profit per dollar of operating cost (profit divided by total operating cost)
1 382
1 368 56% 0.99
Average annual production of Gradaria is slightly less (9 t/ha) compared to production in monoculture (10 t/ha). However, there is an additional production of grass shrimp and crab of about 6.3 t/ha. The total value of annual production is about $4 438, yielding a profit of $2 381/ha. The initial investment can be paid back virtually at the end of the first year of operation. Annual profit of Grucihia polyculture is about 1.7 times higher than that of monoculture, while annual operating cost is about 4.4 times higher. Therefore, the profit rate per dollar of operating cost is higher for monoculture ($0.99) than for polyculture ($0.39)., Polyculture tends to increase the efficiency of land use when land resources are more scarce than capital. Where capital is more scarce than land, monoculture seems more appropriate. MARKET
DEMAND
About 31% of the total Gruciluria production in Taiwan in 1973 was consumed fresh as food. Another 31% was exported as raw material for manufacturing agar. The remaining 38% was processed into agar in Taiwan for domestic and foreign markets. Japan is the major agar-consuming country. Domestic demand for agar in Japan increased from 2 182 t in 1968 to 2 429 t in 1973, with an annual increase of about 2.3% (Agar Producers’ Association, 1974). Japan has been the major agar-importing country due to its declining natural production of the raw materials. In 1972, Japan imported 720 t of agar (an increase of about 43% annually between 1968 and 1972), followed by Britain (654 t), West Germany (626 t), and the United States (536 t). Portugal is the most important agar-exporting country (600-700 t annually), followed by Denmark (about 600 t), Spain and Morocco (about 300 t each), and Korea and Argentina (100-200 t each). Prices of agar in the major importing countries increased significantly during recent years. For instance, the price of agar in Japan increased 56-105% between 1971 and 1973, depending on types of product (powder, strip). Japan has been the most important importing country not only for manufactured agar but also for raw Gracilaria for processing into agar. In 1973, Japan imported about 8 000 t of raw Gradaria, about 47% more than in 1972. The Philippines, Brazil, Taiwan, Chile and Argentina are the major exporters of raw Gracilaria. The average import price of raw Gradariu in Japan was about $500/t in 1973, an increase of about 25% over 1972. When production costs of about $135/t are compared with the average import price in Japan, the culture and export of raw Grucilariu to Japan appears to be a profitable business for Taiwanese Grucilariu growers. The profit is expected to be higher if the raw material is processed into agar for export. CONCLUSIONS
Grucilaria culture in ponds is a labor-intensive operation. Cost of labor ac-
TABLE III Costs and returns of Gracilaria polyculture (per hectare) Quantity
Direct cost Gracilaria Labor Seed stock Fertilizer
132 days 4 000 kg 4 000 kg
Percentage
330 200 100
5.4 3.3 1.7
630
10.4
1 500 350 100
24.8 5.8 1.7
1950
32.3
1 000 1 250 50
16.5 20.6 0.8
2 300
37.9
750 134 250 43
12.4 2.2 4.1 0.7
Subtotal
1 177
19.4
Total cost
6 057
Subtotal Grass shrimp FrY Feed Labor
40 000 individuals
Subtotal Crab Fry Feed Labor
10 000 individuals
Subtotal Indirect cost Management Depreciation Tax and maintenance Lease
Revenues Gracilaria Grass shrimp Crab
12 months
9.0 t (dry) 4.8 t* 1.5 t*
Total revenue
Profit
2 475 2 400 3 563 a 438
2 381
Rate of return on initial investment Profitper
Amount ($)
dollar of operating cost
*Survival rate is 60%.
98% 0.39
29.3
28.4 42.2
7
counts for over 50% of total operating expenses. However, Gruciluriu is a fast-growing seaweed. Annual production rates of 10 t/ha (dry weight) can be attained. In addition, Gruciluria culture requires lower initial operating expenditure than many types of aquaculture. Annual profit can reach $1 399 -$2 413/ha. By comparison, profits from milkfish culture are about $250-500/ha. It is not surprising that many milkfish ponds in Taiwan are being converted to Gruduriu culture. Owing to relatively low labor costs in Taiwan, it is likely that Taiwan’s share in supplying the growing world market for Grucilariu and agar will increase, if production can be expanded. The increasing demand for Gruciluriu and agar and the over-harvesting of natural stocks have resulted in a rising price in the world market. These circumstances likely will encourage the culture of Gruciluriu not only in Taiwan, but also in other developing countries with suitable sites for its cultivation. ACKNOWLEDGEMENT
The author expresses his thanks to Dr John E. Bardach for his helpful ments on the preparation of the manuscript.
com-
REFERENCES Agar Producers’ Association, 1974. Agar Intelligence. Tokyo, February, (in Japanese). Chen, T.P., 1975. Culture of Gracilaria. Taiwan Fisheries Consultant, Inc., Taipei, unpublished manuscript. Cheng, C.C., 1974. Gracilaria Culture and Agar Processing Industry in Taiwan. Joint Comm. Rural Reconstr., Taipei, 23 pp. (in Chinese). Lin, M.N., 1974. Culture of Gracilaria. Fish. Res. Inst. Keelung, 8 pp. (in Chinese). Mathieson, A.C., 1975. Seaweed aquaculture. Mar. Fish. Rev. Nat1 Mar. Fish. Serv., U.S. Dep. Commer., Seattle, Wash., 37 (1) 2-14. Taiwan Fisheries Bureau, 1973. Survey of Production Costs of Fisheries in Taiwan. Taipei, 86 pp. (in Chinese).