Seaweed: Underwater gold mine

Text and Photos By Henrylito D. Tacio
“There is a need to produce more seaweeds in the Philippines. The global demand is big and is growing by leaps and bounds. That’s because seaweed products are used in a wide range of industries,” reported Zac B. Sarian in his monthly column in a recent issue of Agriculture.
The source of his information was Maximo Ricohermoso, chairman of the Seaweed Industry Association of the Philippines. He was the main speaker of the technology forum of Seaweed Fiesta that was held at the Passig Islet in Sta. Cruz, Davao del Sur recently. It was convened by the Philippine Council for Agriculture, Aquatic and Resources Research and Development (PCAARRD), a line agency of the Department of Science and Technology.
The gathering, which was co-sponsored by the Davao-based Southern Mindanao Agriculture and Resources Research and Development Council (SMARRDEC), was made “to report the latest developments in the project while at the same time hoping to inspire other people to get into seaweed farming.”
One of those who attended the gathering was 41-year-old Ethelmark Bohol of Baganga, Davao Oriental. He grows two kinds of seaweed: Eucheuma alvarezzi and Kappaphycus cottoni.
The first one is known locally as “Bermuda,” which is highly suitable for eating as part of a fresh salad. Sarian reported that Bohol grows 10 lines of seaweeds, each line measuring 220 meters long. From this, he harvests 5-10 kilos each day and sells them at P30 per kilo in the local market.
As for the second type of seaweed, the color is very white and seems to have been bleached without using any bleaching agent. Actually, the original color is brown but it when sundried, soaked in water overnight, and then sundried again, it becomes very white. So white that it can be used a replacement for the usual “buko” in a fruit salad.
While there is money in growing seaweeds, the industry is still beset with problems. Foremost is marketing of the produce. Sarian, in his column, wrote: “Seaweed growers in remote areas with poor transport facilities have a problem with marketing. Government assistance is needed so more people will go into seaweed farming.”
If there’s no financial support from the government, the industry will remain a promise without fulfillment. As Sarian puts it: “Even if they (farmers) can produce a lot of seaweeds, if they cannot market their harvest as a profit, they will just look for other projects to undertake.”
In a primer, the PCCAARD identified the coastal villages of these provinces as the leading producers of seaweed: Western Mindanao, Central and Eastern Visayas, and Southern Tagalog. They reportedly account for more than 60 percent of the country’s production.
Seaweeds are marine plants that grow abundantly in shallow reef flats and in lagoons with a water depth of less than two meters at high tide. They differ from plants because they lack the stems, leaves, roots, and vascular systems that are common in higher plants.
Technically, seaweeds are “multicellular” forms of algae and are classified into three main divisions: brown algae, red algae, and green algae. Brown algae, commonly called “kelp,” are the largest variety. Pacific species can reach 65 meters in length and have structures that superficially resemble leaves and stems.
On the other hand, red algae are composed of several species, including the Irish moss. They are abundant in clear tropical waters. Meanwhile, green algae – which are sometimes called “sea lettuce” – are commonly seen at low tide, along rocky shores in northern seas.
The Philippines is one of the pioneers in seaweed farming. Cultures of Porphyra, Eucheuma, and Caulerpa in the Philippine marine farms have been recorded as early as the 1960s. Through the initiative of Dr. Max Doty, a marine botanist at the University of Hawaii, and his local counterparts, the first technology for culture of Eucheuma was introduced to industry in 1973.
Commercial seaweed farmers first succeeded in cultivating Eucheuma in the reef areas of Mindoro, Aklan, Cuyo, Zamboanga, and Tawi-Tawi. Since then, seaweed production has gone overboard.
Ideally, the conditions for growing the seaweeds are water depths of one foot to two feet at low tide, water temperature of 27 to 30 degrees Centigrade, salinity of 31 to 34 parts per thousand and moderate water movement (20 to 40 meters per hour). Excessive sunlight, strong currents, and the presence of plant-eating fish like danggit (siganid) can be detrimental to seaweed growing.
In the Philippines, some 390 species have been identified as having economic value as food, animal feeds, fertilizers, diet supplement, medicines, and raw materials for industrial products.
At least 60 Philippine varieties are reportedly edible, including “gulamang dagat,” “gamet,” “pocpoclo,” “culot,” “lato,” “guso,” “barls-barls,” “bulaklak bato,” and “balbalolang.” Some of these varieties can be processed into jams, jellies, candies, pickles, baby’s food, and “gulaman” bars.
The food value of seaweeds varies in different species. Average chemical analyses of 46 species of marine algae in the Philippines show that the crude protein content (percentage of dry weight) is 7.44, 6.40, and 9.29 for the green, brown, and red seaweeds, respectively. This is about two to three times the protein content of common green leafy vegetables, which is 3.27 percent dry weight.
Four species – Halimada, Hypnea, Sargassum, and Asparagopsis – have been used as feed or fodder for livestock. Species of Cladophora, Enteromorpha, Chaetomorpha, and Gracilaria are used to supplement or substitute for fishfood for cultured herbivorous fish.
The high potassium content of brown seaweeds like Sargassum, Turbinaria, Hormophysa, and Hydroclathrus make them ideal substitutes for costly fertilizer. In Kidapawan City, North Cotabato, Jose Riga has developed an all-purpose seaweed-based organic fertilizer and soil conditioner in stabilized pellets. The fertilizer, called Sea Crop, is made from brown seaweed, cattle manure, stabilizing compounds and an organic binder fortified with soluble compounds of a number of nutrients.
Seaweeds have also some medicinal values. They are used to treat or prevent goiter, glandular troubles, stomach disorders, intestinal and bladder difficulties, unusually profuse menstrual flow, high-blood pressure, and high plasma-cholesterol level. Gracilaria species are used locally as pain relievers and ointments.
Commercially, seaweeds are valued for their colloids or gluey substance, particularly agar, carrageenan, and algin. Both agar and carrageenan are extracted from red seaweeds, while algin is extracted from brown seaweeds.
Agar, which derived its name from the Malay word for seaweed, “agar-agar,” is used in making jellied desserts, as stabilizer in pie fillings, piping gels, icings, cookies, cream shells, and as thickening and gelling agent in poultry, fish and meat canning.
In the medical and pharmaceutical industries, agar serves as a laxative, suspending agent for barium sulfate in radiology, ingredient for slow-release capsules and in suppositories and surgical lubricants, and as a disintegrating agent in tablets. It is also used as impression materials to make accurate casts in prosthetic dentistry, criminology and tool manufacturing.
Carrageenan, on the other hand, is used in making ointments, as a stabilizing agent in frozen dairy products, as emulsifying agent in water-insoluble drugs and herbicides, and as texturing agent in toothpaste and powder. The Philippines is the world’s top carrageenan exporter.
Algin or alginic acid, meanwhile, is used as another stabilizing agent for several food products, as a sizing agent in paper manufacture, and as thickening agent in print pastes and painting coatings.

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