Rizalina M. Legasto
The Philippines has abundant aquatic resources. Seaweeds are one of these aquatic products which are found in lagoons and reed areas all over the country. The country is one of the few in the world which pioneered in the farming of these plants in substantial quantities.
Seaweeds are a good source of colloidal materials which are used as gelling agents, emulsifiers, stabilizers, in pharmaceutical, cosmetic and food products. They also constitute an important food item, fertilizer and animal feed.
In 1966, seaweed was a negligible item in the country's economy. Export at that time amounted to only 800 MT. With the development of seaweed farming in 1973 foreign revenues increased to almost fifty times. Since then what has been a minor sea products is now generating P466,732,486 or about US$ 23.4 M (32.3 thousand MT) for the country and now the third most important fishery export of the Philippines.
II. Existing seaweed resources
Production of seaweeds in the Philippines depends on natural stock except for Caulerpa and Eucheuma which are produced through mariculture. Limited information is available on other commercially important seaweed such as Gelidium, Sargassum, etc.
Among the various seaweeds found in the country, Eucheuma is the dominant species. Eucheuma alvarezii (cottonii type) and Eucheuma denticulatum (spinosum type) are commercially cultivated in the country. Eucheuma a red alga is an important source of raw material for carrageenin, a colloidal substance used as gelling agent, stabilizer or emulsifier in food, cosmetics and other products. Gracilaria is the raw material for producing agar which is used in food and pharmaceutical products and as culture media for research laboratories.
Gracilaria is harvested mainly in Manila Bay and provides income to coastal communities in Bataan and Cavite. Unfortunately, it is of inferior quality due to pollution of these areas. Gathering of Gracilaria is also undertaken in Buguey, Cagayan and sold at P2.00/kg. These are sold in Manila and gathering is undertaken only as secondary to farming.
Sargassum, a brown seaweed containing alginate is known locally as samo. It can be used as food and in pharmaceutical products. The Sargassum industry developed in Misamis Oriental in 1978. This seaweed grows abundantly in the shallow coastal waters in the country. It is used as an insect repellant and feed supplement for poultry and livestock. Harvesting usually done during the months of January-June is by hand picking.
* Extension staff, Bureau of Fisheries and Aquatic Resources, Metro Manila, Philippines.
Caulerpa is utilized as a vegetable and sold both in the foreign and local markets. About 400 hectares of ponds are utilized in Caulerpa farming in Mactan, Cebu. Retail price in Metro Manila range from P20–22/kg.
Hydroclathrus is used mainly as a food item in Pangasinan and sold at P80.00/can.
Other species such as Codium, Porphyra, Digenea simplex, and Gelidium are also utilized in the country but very little information is available on their usage and production.
III. Seaweed export
Seaweeds exported to other countries come in the form of dried, fresh or salted or as seaweed meal powder. Cultured Eucheuma is sold in the international market in semi-refined and refined forms. A portion of the local produce of Gracilaria and Gelidiella are processed into crude agar which are sold in the local market in the form of dried agar bars.
A small amount of Caulerpa is sent to Japan in dehydrated or salted form. Sargassum is processed in Central Visayas and exported to Japan. A significant amount of Gracilaria and Gelidiella is exported while the rest is locally produced into agar bars. Production of Codium and Porphyra is dependent on natural stocks and are consumed locally.
The bulk of dried seaweeds goes to Denmark and U.S.A. Japan is the biggest importer of salted seaweeds and seaweed meal. Other countries which buy sizeable amounts of seaweeds from the Philippines include Taiwan, Australia, Ireland, Kuwait, New Zealand, Hungary, France, Thailand, Spain and West Germany.
IV. Cultivation and post-harvest processing
The present farming of Eucheuma utilizes the monoline or bottom and floating methods.
Seaweed farms range from 2,500–5,000 m2 and farmers use 10-meter nylon lines. Seaweed cuttings weighing about 150–200 g are attached to these lines with the use of plastic straw. These are suspended and attached to wooden stakes. The distances between lines is at least one meter.
In the floating raft method, the monolines are attached to a rectangular bamboo raft.
The best months for growing are from November to July with March to May as peak growth months.
Harvesting is undertaken after 45 days. The harvested seaweed is sun dried for 2–3 days.
One kilogram of dry seaweeds requires six to nine kg of fresh seaweeds.