The seaweed farm cultures Eucheuma cottonii, locally known as “rumput laut”. It is located in a lagoon in Kuta Bualu, at the southeastern tip of the island of Bali, Indonesia. A narrow sandbar, about 120 m from and parallel to the shore for a distance of 1 km, protects the farm from the big waves of the open sea. At low tide, the water level at the site is only 25 cm deep, at high tide 150 cm. The bottom is sandy-muddy and fertile enough to support a medium density vegetation. The water has a year-round salinity of 30–32 ppt and appears to be free of pollution. While there is a 5-star resort-hotel about 2 km away, the area around the site is devoid of human habitation.
The farm is owned and operated by a part-time farmer assisted by his wife and 2 pre-adolescent children. His main source of income is a small plot of land planted to vegetables about half a kilometer away. Other sources include a couple of cows, whose calf he sells, and seasonal gathering of milkfish fry, which he sells to middlemen.
The seaweed farm has a total area of 780 m2 composed of 7 units separated from each other by a 1.5 m wide aisle. Each unit measures roughly 7 m × 10 m, with 50–70 polyethylene cords, 3/1" dia (9 mm), arranged in horizontal parallels along the unit's length and tied to mangrove and bamboo stakes. The cords are spaced 15–20 cm apart; so are the seaweed fronds attached to them. A unit may thus hold 2 000–3 000 plants. The 7-unit farm has 14 000–21 000 plants.
It took the farmer some time to accumulate the large number of plants because he started his farm only with what plants he could get from the wild and the little help extended him by his neighbours. He constructed the 7 units with mangrove and bamboo stakes he gathered himself. The cords he bought for a total of Rp 20 000. The stakes are replaced every 6 months but the cords last 2–3 years.
The seaweeds are harvested every 2 weeks at low tide using only the fingernails to snip the branches from the parent plants. In the process, sick and dead plants are removed and replaced with healthy ones. Every 2 weeks, a unit produces a minimum of 1 sack of wet seaweeds weighing 35 k. Eight sacks of 35 k each wet, totalling 280 k, produce a sack of sundried seaweeds weighing 100 k. Depending on the duration and intensity of the sunlight, the wet seaweeds can be dried in 8–24 hours.
The dried seaweeds are sold to a buyer who takes it to Surabaya and sells it to an exporter. These are exported to Singapore and Sweden. Two years ago, the dried seaweeds sold for Rp 240/k. The current price fluctuates from Rp 140 to 200/k. A monthly income of about Rp 28 000-Rp 40 000 from the seaweed farm is obtained. This level of income is comparable to the average national per capita income of Indonesia (Rabanal,
The farmer cleans the farm regularly, removing sea urchins crabs and other animal predators, uprooting sea grasses and other vegetation, retying loosened plants, removing debris, etc. He works 1–2 hours daily at times with his family. He would also like to build a net fence around the farm to prevent fish from feeding on the plants. These predators are locally known as “tabasan” and “elak”. However, lack of funds inhibits him from constructing the fence.
The technology involved in the farming of seaweeds for small-scale production is simple enough to be easily understood and copied by ordinary fishermen. However, they should be informed about some of the more important factors. Among these should be the minimum depth of water at low tide. In the project described, the depth of 25 cm is too shallow. Double this depth or a few cm more could be ideal. They should also know the importance and necessity of not allowing animal predators from reaching the plants. And most important, dried seaweeds should be clean and free of debris or any foreign matter, particularly weight-adding sand.
Estimate Cost of an 8-Unit (86.0 m2 ) Seaweed Farm
(US$1 = Rp 1 300)
| A. | Capital cost | |||
| Rope - 15 rolls (9 mm dia, 200 m/roll) and nylon twine (for tying) | Rp 17 600 | |||
| Bamboo or mangrove stakes - 32 pcs | 3 000 | |||
| Miscellaneous equipment (sacks, raft, mat, etc.) | 3 000 | |||
| Sub-total | Rp 23 600 | |||
| B. | Operating expenses (2-week period) | |||
| Minimal | Rp 2 200 | |||
| Total budgetary outlay | Rp 25 800 | |||
| C. | Estimate gross sale (every 2 weeks) | |||
| Production - | 35 k wet/8 units/2 weeks | |||
| 2.8 k wet - 1 k dry | ||||
 | Rp 14 000 | |||
| D. | Total estimate annual gross income | |||
| Rp 14 000 × 20 weeks | Rp280 000 | |||
The Philippines has a substantial production of seaweeds particularly Eucheuma cottonii. In 1984 more than 10 000 tons of dried seaweeds were exported. The increasing demand of the colloid market makes it an attractive option for the expansion of seaweed farming. This type of farming is compatible with coastal resource protection and conservation,
A 1,0 seaweed farm yields 8,0 tons (dry weight) with extensive management while an intensively managed seaweed farm produces 20 tons (Smith and Pestaño-Smith, 1980), Current market price per kg of seaweed is 
8.00 dry weight (BFAR, 1984).
Cost and Return Analysis of a 1-ha Eucheuma Farm*
| Life (Years) | Cost | |||||
| A. | Initial investment | |||||
| 1. | 30 kg nylon #200 at 75/kg | 2 | 2 250 | |||
| 2. | 1 100 mangrove stakes/posts at 0.25 each | 1 | 275 | |||
| 3. | Storage and drying platform (farmhouse) | 5 | 3 000 | |||
| 4. | Four pes bull hammers at 150 each | 10 | 600 | |||
| 5. | Four pes iron bars at 60 each | 10 | 240 | |||
| 6. | Ten baskets at 18 each | 1 | 180 | |||
| 7. | One dug-out banca | 8 | 3 000 | |||
| Total fixed cost | 9 545 | |||||
| B. | Production cost | |||||
| 1. | Operating cost | |||||
| a. | 50 000 seedlings at 200 g each (10–000 kg) at l.00/kg1 | 10 000 | ||||
| b. | Four laborers at P30/day for 100 working days yearly2 | 12 000 | ||||
| c. | Repairs and other expenses | 1 500 | ||||
| d. | Four splitters/tiers at l8/day for 100 working days
years3 | 7 200 | ||||
| e. | 60 rolls plastic straw at 33/roll | 1 980 | ||||
| Sub-total | 32 680 | |||||
| 2. | Depreciation | |||||
| a. | Nylon line | 1 125 | ||||
| b. | Mangrove stakes/posts | 275 | ||||
| c. | Storage and drying platform | 600 | ||||
| d. | Bull hammers | 60 | ||||
| e. | Iron bars | 24 | ||||
| f. | Baskets | 180 | ||||
| g. | Dug-out banca | 375 | ||||
| Sub-total | 2 639 | |||||
| Total production cost | 35 319 | |||||
| C. | Harvest | |||||
Initial seedlings of 50 000 at 200 g each 5 percent daily growth rate or maturing to 1 000 g each | 40 000 kg | |||||
| Less: | ||||||
| a. | Seedlings for replanting (10 000 kg) | |||||
| b. | Biological losses 10 percent (4 000 kg) | 14 000 kg | ||||
| Net fresh harvest | 26 000 kg | |||||
About 7 kg fresh seaweed is needed to produce 1 kg dry weight at approximately 35 percent moisture - total dried harvest | 3 714 kg | |||||
| D. | Sales | |||||
Total sales of dried seaweeds at 4,00/kg* delivered at the warehouse | 14 856 | |||||
| Less: | ||||||
| Transportation at 0.30/kg | 1 114 | |||||
| Net sales per harvest | 13 742 | |||||
| (There are five harvests in one year) | x 5 | |||||
| Net total sales for first year | 68 710 | |||||
| E. | Income Summary for first year | |||||
| Net total sales for first year | 68 710 | |||||
| Less: | ||||||
| Total production cost | 35 319 | |||||
| Net income | 33 39l | |||||
Cost data are based on existing first quarter 1987 prices.
Assumed growth rate is 5 percent daily
A total of five harvests in one year,
* Source: Seaweed Industry Association of the Philippines,
* Price fluctuates from 4.00–7.00/kg.
Eucheuma farm
Seaweed farm houses with drying platforms
Seaweed harvest
Drying of seaweeds
Caulerpa is a kind of seaweed that is used directly for human food. It is a popular salad preparation in Luzon and the Visayan region. The seaweed is locally called “lato” in the Visayas and “ar-arusip” in northern Luzon.
Pond culture of Caulerpa was an accidental development particularly in Mactan, Cebu. A farmer used to throw pieces of Caulerpa in his fishpond thinking that the fish would eat them. It was found later that the algae grew quite well in the pond. Harvesting of the seaweed for food took place which gave the farmer good economic returns. From then on, the fishpond owner engaged in growing Caulerpa as his main crop and fish or prawn became secondary crops in his pond culture operations.
A hectare of brackishwater pond is initially stocked with 1 000 kgs of Caulerpa broadcasted over the pond bottom or planted. After 45 days partial harvesting is carried out. The plants must be grass green and succulent. About one-fifth or one-fourth of the seedstock is retained for subsequent grow out stocks. Harvesting takes place every 45 days thereafter.
Total production of Caulerpa per ha per year reaches up to 15 tons. This level could be higher depending on pond management and experience of the farmer. The retail price of Caulerpa is 20.00-25,00 per kilogram or approximately US$1.00.
Caulerpa harvesting
