2.1. Historical Aspects
2.2. Current Technological Status
Rural aquaculture in the Philippine setting will be difficult to define and appreciate without having to view it against aquaculture in general. Furthermore by reviewing the history of the various species being farmed, one can see which species caught on. Hopefully one can even gather why some species are far ahead while others are left behind in terms of development. Aquaculture in the Philippines has a long history and involves many species and culture systems. Rather than present the history in a strictly chronological order which would involve jumping from one species and one culture system to another, it is here presented by species in the chronological order of their respective introductions.
2.1.1. Milkfish
The exact period when aquaculture gained a foothold in the Philippines may never be known. It is generally accepted however that the earliest fishponds were brackish water fishponds and the earliest species to be grown was bangus or milkfish, Chanos chanos Förskal, using naturally occurring fry that came in with tidal waters.
The generally held belief is that brackishwater fishponds probably had their origins in the island of Madura or in East Java. Herre and Mendoza (1929) cited the Dutch author C. Th van Deventer as having recorded that a Javanese law codified in 1400 A.D., already provided punishment for “him who steals from a tambak.” It is likely that when the Spanish conquistadors, led by Ferdinand Magellan, set foot on the island of Cebu in 1521, there were probably already fishponds on Mactan Island where he was slain. Herre and Mendoza noted that the ancient style of fishponds continued until 1921 in Mactan. The Indonesian word for fishpond, tambak, also means an embankment, an earthen dam or to bank up earth (Echols and Shadily, 1989). Tambak also means embankment, heap of earth or to pile up in Tagalog (English, 1986).
For a very long time, aquaculture industry in the Philippines was virtually synonymous with milkfish culture. And for a very long time milkfish farming remained as a brackishwater operation watered purely by tide, and relying totally on natural-food and naturally occurring, and later, wild-caught seedstock. Even under such condition milkfish farming developed into a highly sophisticated art involving a long preparation period to grow the natural food and a series of ponds to nurse the fry to fingerling stage. This eventually culminated in the development of the modular method that provides for a series of progressively larger ponds to accommodate the fish stock as they grow and at the same time allow for a certain degree of overlap between cycles. Other methods such as the stock manipulation method was introduced by an FAO expert and the deep water method by a USAID Project. However these never really caught on.
In the early seventies, milkfish farming operation expanded to include culture in bamboo and net pens set in Laguna de Bay - the country’s largest freshwater lake (Delmendo and Gedney, 1974). Then in the early 1990s, milkfish culture in fishpens spread as well to shallow marine bays and estuaries particularly in the Lingayen Gulf area. It did not take long for its culture to spread to net cages whether fixed or floating in both freshwater and marine setting.
Up to this time the technologies used were purely indigenous. However in 1996, the first Norwegian cages, heretofore used for salmon, were tried in Sual Bay, Pangasinan along the western coast of Luzon. The results exceeded expectations and now there are some 72 Norwegian cages within the area (dela Vega, 1998). Following close in its heels, the American-designed submerged cages were also introduced off the eastern coast of Luzon. The much higher cost of the latter and the 35 percent drop in the value of the Philippine peso limited its introduction to no more than three units. A local company is now manufacturing circular net-cages patterned after the Norwegian model but with innovations to suit the local conditions (Cruz, 1998).
The introduction of the marine cages has greatly expanded the range of culture systems under which milkfish is now being produced: brackishwater ponds, fishpens in freshwater lakes, fishpens in shallow bays, lake based cages whether fixed or floating, and sea-based cages. No other aquaculture species probably has a wider range of environment and culture systems under which it is being produced.
The culture of milkfish in cages depended upon and was hastened by the development and marketing of commercial feed by the feed millers. As mentioned earlier, milkfish farming for a long time depended totally on natural food. Sometime in the mid-1950s, intensive milkfish farming started in Negros Occidental, erstwhile center of the country’s intensive prawn culture operations.. The impetus was the continued setbacks suffered by the prawn growers due to diseases brought about by over-intensification. Many went back to milkfish farming. However having enjoyed the high value of prawns and having experienced the large volume of harvest in intensive prawn ponds, many were not content to go back to the fertilizer and natural food based milkfish culture system with their relatively low yield which also was very weather-dependent..
With their existing infrastructure which included huge pumps and pond aerators, it was not difficult for them to apply intensive culture techniques to milkfish. This proved to be a boon to the feedmillers who were suffering a slump in sales in prawn feed. In order to utilize their existing capacities, most if not all of them diversified their product line to include fish feed. In fact the sudden popularity of milkfish feed may have been a “technology-push” situation where the feed millers in their attempt to stay in business sold the idea of intensive milkfish culture to the losing prawn growers. Where previously milkfish farmers were content to merely use rice bran as a supplemental feed when the natural food collapses or is depleted, many now use commercial pellets.
The technology to spawn the milkfish in captivity and produce fry in a hatchery was developed in 1979 by SEAFDEC Aquaculture Department. With the initial success in rearing the fish to maturity leading to spontaneous spawning in captivity, a National Bangos Breeding Program was launched in 1985. Somehow unlike in Taiwan and in Indonesia, commercialization proved elusive. Both the banks and any would be investor were discouraged by the long gestation period involved since it takes five years for the fish to reach maturity.
It was not until 1996 when a local industrialist decided to invest in a milkfish hatchery. But when they did they turned to Taiwan for both the full-grown breeders and the larval rearing technology. Hatchery produced milkfish fry are now available but most growers still prefer to use wild fry. This is believed to be temporary. It can be recalled that there also used to be considerable resistance among prawn farmers on the use P. monodon fry from a hatchery.
2.1.2. Carps and Other Freshwater Fish Species
Not counting the rice paddies which in a way also served as part-time fishponds and which also has a long history, freshwater fishponds which are deliberately developed as such, probably came much later. There is no record on when the first such fishpond was established but there are records of the early introduction of exotic fish species that presumably must have been, at some time, held in some form of containment, which most likely was an earthen pond. Introductions of exotics started as early as 1905 with the three different species of mosquito fish from Honolulu, Hawaii in 1905. This was followed by the black bass Micropterus salmoides from California, USA.
The first exotic food fish with potential for aquaculture was introduced only in 1915 with the entry of the common carp, Cyprinus carpio in 1915 from Hongkong (Villaluz, 1953). These were stocked in the swamps and freshwater lakes of Mindanao in 1916 and 1918. Villaluz recounts that when 16,000 carp fingerlings from China in 1925, these were stocked in the fishpond of the then Bureau of Science. The fishpond probably refer to 10 x 20 meter rectangular tanks which were built fir use by the Division of Fisheries or the Fish and Game Division of the Bureau of the Bureau of Science (Rabanal, pers. comm.)
Since then several other freshwater fish species were introduced, including the giant gourami from Thailand in 1927 and the various plasalid species (Trichogaster spp.) in 1938. The big head, silver carp and the Indian carps were also introduced in the 1967 to 1968. Carp and gourami continues to be reported from freshwater fishponds, but somehow freshwater fishponds never caught on. Several species introductions and several years later the industry is nowhere the magnitude of brackishwater fishponds and remains largely a backyard type operation. It was not until the Nile tilapia was introduced and became popular that freshwater fish farming assumed some level of significance. Due to its importance Tilapia shall be discussed separately by itself in a latter section.
The failure of freshwater fishponds to catch on is probably due to two factors. One, good agricultural land is considered too valuable to be dug up for fish culture. And, two, due to the abundance of marine catch and the island nature of the country, freshwater fish is still not as widely accepted as marine fish. There are areas where freshwater fish may be preferred but these are highly localized. Until now it is not rare to find Filipinos who refuse to eat freshwater fish.
2.1.3. Oysters and Mussels
The farming of oyster in the Philippines was said to have started as early as 1931 when an oyster farm was established in Hinigaran, Negros Occidental employing the broadcast method of culture (Rosell, 1992). Then either in 1932 (Ronquillo, 1992) or 1935 (Rosell, 1992) the then Bureau of Science introduced improved methods in Binakayan, Cavite. Until now Binakayan is still a major oyster producing center. For a long while, oyster farms were confined largely to the Manila Bay area with only isolated and sporadic operations found in a few localities.
The practice has now spread to many parts of the Philippines up to Mindanao in the south. The broadcast method wherein empty oyster shells are merely scattered on the bottom of a know oyster bed is still practiced particularly in certain areas where the installation of any structure may hinder navigation as in Tinagong Dagat in Capiz, but most farms now use off-bottom techniques. The cultch, or type of substrate used range from empty shells of oysters and other bivalves to bamboo alone or in some cases used automotive rubber tires. The structure used could be as simple as bamboo stakes or could be a more elaborate set up using racks from which the cultches that are strung together with nylon monofilament fishing lines are suspended.
The farming of mussels started 20 years after, in 1955 when the Bureau of Fisheries oyster farming station in Binakayan, Cavite established a 300 m2 demonstration mussel farm (Rosell, 1992). Prior to this the green mussels, Perna viridis, were regarded by the oyster farmers as pests. The fisheries personnel however realized the potentials of the species as a primary crop in itself and decided to put up the demonstration farm. With a ready market in Manila it did not take long for the mussel industry to grow. During the late 1960s, the Mr. Santos B. Rasalan then Commissioner of the Phillippine Fisheries Commission (as the Bureau of Fisheries became known at the time) reportedly also brought in green mussel stocks from Thailand and replanted these in the fisheries demonstration farm. What effect these had on the stock is not known.
It was only in the middle to late 1970s however that mussel farming spread outside the Manila Bay area. This was mainly due to the green mussels’ limited occurrence. Prior to the 1970s they were never reported outside Metro Manila. The most widespread mussel species in the Philippines is the brown mussel, Modiolus metcalfei. The brown mussel occurs as a dense mat on the bottom of shallow bays. Unlike the green mussel, it is not known to settle on artificial substrates, but instead prefers to settle on the valves of the grown mussels (Yap, 1979). Because of such settlement habit, it has a low potential for aquaculture and in fact has never been farmed.
Probably due to increased communication between islands, the green mussel eventually became established in other bays. They could have been unintentionally introduced through the bilge water of the ships plying the islands. Most notable are Sapian Bay and Batan Bay in the island of Panay and Maqueda Bay in the island of Samar. This did not occur until the mid-1970s. Once the their presence were noticed on fish traps and pilings, it did not take long for people in the locality to venture into their culture.
The most common method uses whole lengths of bamboo poles simply stuck into the soft muddy bottom of known mussel beds. If a good spat settlement occurs soon after installation, the first harvest can be realized in as short as six months. This method that started in Binakayan, Cavite in 1955 is still the most popular due to its simplicity. Although bamboo is now relatively expensive and sometimes difficult to find, the method still persists.
A one-hectare commercial venture using polypropylene ropes as substrates was made in Sapian Bay in 1976 to 1979, not surprisingly by one of the country’s largest rope manufacturer. This can be considered a large-scale venture in as much as most mussel farms range between 300 to 1,000 m2. Instead of hanging vertically from a raft, the ropes were formed into large 5 m long webs which were then stretched across a bamboo framework set on the bottom of the shallow bay. The farm was reported to have harvested 600 mt of mussels during the first year of operation. The farm was not sustained, partly due to marketing problems.
The use of ropes suspended from a raft similar to that of Spain or from a buoy and long line contraption similar to that of New Zealand had also been demonstrated successfully at one time or another. However the preferred method is to stake bamboo poles into the muddy bottom singly a meter apart in 2 to 10 m deep water, or in a cluster around a central pole, resembling the framework of a Native American tepee, to provide some stability.
The bulk of oysters and mussels are sold live. A small amount may be shucked and sold shell-off either fresh or salted. With improved transportation lines, mussels from Maqueda Bay on the island of Samar now reaches Manila market or even northern Mindanao.
During recent years mussel and oyster farmers have been faced with the red tide problem. Extremely rare before, red tide is now occurring with increasing regularity. It has also spread outside Manila Bay. It seems all the major mussel producing areas are now regularly having red tide blooms. Due to several deaths in the past the government has a regular red tide monitoring program. Whenever the red tide organisms exceed a certain threshold level, a complete ban is imposed on the harvesting and sale of oysters, mussels and all other bivalves. In the interest of public safety, even bivalves from a red tide free area are not allowed into the lucrative Manila market to prevent surreptitious harvesting from the red tide positive area. Needless to say the shellfish ban always wrecks havoc on the livelihood of the families relying completely on the production or trading of mussel and oyster.
2.1.4. Penaeid Shrimps
The culture of penaeid shrimps in brackishwater ponds is probably as old as the culture of milkfish since they always occur together especially when the fish farmers were still merely dependent on the entry of wild fry. Normally it will be a mixed harvest milkfish, the jumbo tiger shrimp Penaeus monodon; the white shrimps P. indicus and P. merguiensis and perhaps the greasy-back shrimp, Metapenaeus ensis. But because only a relatively small quantity can be harvested with the milkfish, it was always considered only a secondary species. It was only in 1951 when the culture of P. monodon as a primary species was first advocated by Villadolid and Villaluz (1951). Delmendo and Rabanal (1955), made the first documentation on their growth and their culture in brackishwater ponds.
Even after that, P. monodon remained in its position as a secondary species to be stocked with milkfish. The industry just could not develop fully with the meager supply of wild-caught fry. Its full commercialization has to wait for the development of hatchery technology. This was not to happen until the mid 1970s after the successful reproduction of P, monodon in captivity (Villaluz et al, 1972). However it was during the 1980s that the industry really took off. Fueled by a booming Japanese market, large business concerns, many with no prior exposure to aquaculture, ventured into hatchery and grow-out operation. No other aquaculture species has so captured the interest of big business. The jumbo tiger became the Philippines top marine product export earning at its peak in 1992 some USD 300 million.
With so many hatcheries being put up fry supply ceased to be a major constraint. For a short while the problem shifted to the adequate supply of quality feed. But with many feed mills getting equipped to produce prawn feed often through tie-ups with Taiwan-based companies, commercial feed became widely available. Some milkfish ponds were converted fully to shrimp farming. Others retained their fish production area or stocked shrimps together with the milkfish, or rotated shrimps with milkfish depending on the prevailing salinity. Many growers particularly in the province of Negros Occidental equipped themselves for intensive monoculture. While many more, particularly in the Central Luzon provinces of Bulacan and Pampanga, were content with low-density culture. In Negros Occidental, the rise of the prawn industry happened to occur when sugar, the province’s major industry, collapsed when the Philippines lost its dominance in the world sugar market. Without any second thoughts shrimp ponds were carved out of portions of the sugar cane plantation, even if it involved the bringing in of saltwater.
With banks pouring in money for shrimp production, capital was not a problem. Even as the Philippines went through a political upheaval that started in 1983 and climaxed in 1987 with disastrous effect on the economy, there was no stopping shrimp culture development. Even a series of coup d’etats in the late 1980s failed to dampen the industry. It took an external factor - the long illness and subsequent demise of the Japanese emperor in 1989, to finally put a damper on the burgeoning industry. The price collapsed and suddenly financial projections cannot be met even if production targets could be attained. It was at this time also, when due to political instability, bank-lending rates where at their highest, often reaching more than 25% p.a. Many growers found themselves insolvent. The shrimp fever was over.
Soon after, during the early 1990s, the ill effects of pushing production to the limits using high stocking densities led to diseases, mainly luminous vibriosis. Initially the diseases could be managed with the use of antibiotics. However with unmitigated use of wide spectrum antibiotics the disease bacteria developed resistance and no amount of antibiotics would work anymore. One intensive farm after another collapsed particularly in the province of Negros Occidental, the center of intensive shrimp farming. Elsewhere many of the shrimp farms remain largely extensive. It was these farms which prevented the shrimp culture industry in the Philippines from total collapse as it did in Taiwan.
The white shrimps and the greasy-back shrimps continue to be part of brackishwater aquaculture but shrimp culture in the Philippines has become synonymous with P. monodon culture. There is a good price for white shrimps but the growers still have to rely on wild-caught fry. While it is easy to produce P. indicus or P. merguiensis fry, hatchery operators are reluctant to produce them because the production cost is just as high as for P. monodon but the fry can never be sold at the same price. Since they do not grow as big, shrimp growers will never be willing to buy white shrimp fry at the same price as tiger shrimp fry.
2.1.5. Mud Crab
The mud crab or mangrove crab, Scylla spp, like the penaeid shrimp is also one of the species that may be harvested together with milkfish in brackishwater ponds. However its culture as a crop in itself is fairly recent and probably dates back only to the 1960s. This was when bamboo fencing were used around a brackishwater pond to prevent them from crawling out. Culture density is typically low (20,000 per ha or lower). Previously known only as Scylla serrata, four distinct species are now recognized but their nomenclature is still not quite settled.
Feed used ranges from dead chickens from poultry houses to “trash fish” from capture fisheries or from brackishwater ponds such as naturally occurring tilapia which is considered a pond pest. There is no trash fish as such in the Philippines since almost all species, big or small, are utilized as direct human food. Occasionally on a seasonal basis, the catch may be so much that the selling price drops below a threshold level that makes the fish affordable as feed. Often times what passes for trash fish are those which are no longer suitable for human consumption due to poor handling. The uncertainty of trash fish supply and their often high cost forces growers to be creative in sourcing their animal protein for feeding a carnivorous species such as crabs.
With increasing demand both from both domestic and export market, more and more brackishwater fishpond operators are engaging in crab cultivation. Some operations are no more than fattening of already grown but emaciated crabs, or on-growing half-grown crabs. Some enterprising growers actually purchase the “rejects” (under-sized or under-weight), which remain unsold from the public market for this purpose.
One of the most recent method of growing crab that has emerged is mudcrab pen culture in a mangrove area. This method bears watching because it requires a very low investment and therefore can be promoted as a livelihood option for the coastal poor. This is considered a “mangrove-friendly” aquaculture system in that it does not require the cutting of any mangrove trees or extensive excavation and dike construction. Basically a net pen is installed within the mangrove forest to serve as enclosure for the crabs. Shallow trenches are dug inside the pen area to serve as refuge of the crabs during low tide, (Baliao and de los Santos, 1998; Triño and Rodriguez, 1999).
The biggest constraint to its full expansion is the supply of crab juveniles or seedstock locally called “crablets”. Work on crab larval rearing in the Philippines started as early as the mid 1970s but past attempts were at most sporadic rather than sustained, and survival rates had always been low and inconsistent. Recently however work at the SEAFDEC Aquaculture Department in Tigbauan, Iloilo is yielding more consistent results with improved survival at a level which could make crab seed production economically viable. The technology as of 1998 is in the field verification stage and is in the process of being packaged for dissemination within 1999.
2.1.6. Tilapia
In 1950 the late Dr. Deogracias Villadolid, Director of the then Bureau of Fisheries, brought in the first tilapia (Oreochromis mossambicus) from Thailand (Villaluz, 1953).. Here was a fish which breeds so easily that anyone can be a fish farmer without having to worry about fry supply every time as is necessary with milkfish. Thus it was with the tilapia that the first serious attempt to popularize freshwater fishponds was made.
The backyard pond craze spread out through out the Philippines. Many households with enough space in the backyard or the front yard who had a ready source of water either because of a very shallow water table or the presence of a creek, dug a pond even if it was only as small as 10 m2. Many of these ponds cannot even be drained. Its very advantage, namely the capability to breed in captivity easily, proved to be the tilapia’s undoing. They proliferated inside the ponds and once over-crowded became stunted. It lost is appeal very fast and when they did, the stock that were let loose became a pest. In brackishwater ponds where they were also capable of breeding, the tilapia is considered both a competitor for food and as a predator of newly stocked milkfish or shrimps.
It is generally held that it was only with the introduction of the faster growing Nile tilapia (O. niloticus) in the early 1970s that freshwater aquaculture progressed beyond the sporadic backyard scale or seasonal operations in the past (Aypa, 1992). Later, the introduction of monosex culture as a means of greatly minimizing if not totally eliminating uncontrolled reproduction further made tilapia farming a profitable venture.
The earliest attempt in monosex culture used manual sexing (Guerrero and Guerrero, 1975). Experiments using androgens to produce all male tilapia fingerlings (Guerrero, 1976) showed the feasibility of its commercial application (Guerrero, 1979). The production of genetically male tilapia fingerlings using artificially produced males with YY-chromosome was the next step in monosex tilapia culture (Mair, 1994).
The use of monosex hybrids using either O. hornorum or O. aureus males and O. niloticus or O. mossambicus females, although known since 1960 (Guerrero, 1982) was not practiced or popularized. In 1971 a private grower apparently brought in O. hornorum x O. mossambicus hybrids from Singapore (Guerrero, 1985). There were several independent introduction of O. aureus, in 1977 by the Central Luzon State University, in 1978 by SEAFDEC Aquaculture Department and in 1982 by Israeli consultants of a large commercial freshwater farm in Sta. Rosa, Nueva Ecija. The performance of the O. aureus and O. niloticus hybrids in cages has already been tested (Bautista et al, 1981). Somehow however its use was never popularized and disseminated beyond the farm of the importing agency.
1988 was a landmark year in tilapia aquaculture. It was during that year that the International Center of Living Aquatic Resources Management (ICLARM) initiated a program to developed an improved strain of tilapia for low-cost sustainable aquaculture with funding from the Asian Development Bank (ADB) and the United Nations Development Programme (UNDP) which was to result in the production of GIFT or Genetically Improved Farm Tilapias (Eknath, 1994). The other collaborators to the GIFT Project were BFAR, Central Luzon State University (CLSU) and Norway’s Institute for Aquaculture Research (AKVAFORSK). During the same year the British Overseas Development Agency (ODA) also funded the Genetic Manipulation for Improved Tilapia (GMIT) project. Both projects were done at the Central Luzon State University (CLSU) campus in Muñoz, Nueva Ecija. GMIT on the other hand was carried out at the CLSU Freshwater Aquaculture Center.
It was not until the mid-1990s when both projects were ready to commercialize the research results. Interested tilapia hatchery operators were invited to become accredited GIFT fingerling producers by first undergoing a training program. To continue the work of improving the GIFT Strain, producing and distributing the GIFT breeding stock as well as for licensing interested hatcheries after the GIFT Project officially closed in December 1997, a non-stock, non-profit corporation, the GIFT Foundation International, Inc. was organized (Rodriguez, 1998), to take over the functions of the GIFT Project.
The GIFT requires interested hatcheries to post a cash bond of PHP75,000 per hectare of hatchery/nursery to become licensed GIFT fingerling producers in addition to having the operator and technicians train on the use of the GIFT breeding stock. This entitles the hatchery to use a set number of breeders which continues to be owned by the GIFT Foundation. In addition the GIFT producer pays a royalty based on an agreed number of fingerling each GIFT female is estimated to produce.
Hatchery operators wishing to have their hatcheries become licensed GMT fingerling producers also have to undergo a short training course. No cash bond is required for accredited hatcheries to purchase breeding stock which are sold in sets consisting of one YY-male plus three females at PHP150.00 per set (about US$3.90). Like the GIFT the production and distribution of the breeding stock shall also be perpetuated through a Foundation.
It is however believed that the real expansion in tilapia production can come only with the development of saline-tolerant tilapia because the fishpond industry in the Philippines is virtually synonymous with brackishwater culture. It is for this reason that there has always been considerable interest among the research centers to produce a saline-tolerant tilapia strain. Early attempts showed that fast-growing, salinity tolerant fish can be produced by crossing O. mossambicus and O. niloticus (Guerrero and Cornejo, 1994; Dureza et al, 1994). It was only in 1998 that a commercial farm located in Negros Occidental started promoting a saline-tolerant all-male, hybrid tilapia fingerlings, as a viable alternative to milkfish in brackishwater or saltwater ponds. The strain the said farm is promoting is reportedly a male O. hornorum and female O. mossambicus cross.
The interest in the saline-tolerant tilapias has now gone beyond its possible use for marine cage culture or as a milkfish substitute in brackishwater ponds. The pioneering farm mentioned earlier, as part of its marketing strategy, is promoting their saline tilapia as a viable solution to the disease problems plaguing the prawn growers. The said farm demonstrated that the presence of a fairly large tilapia biomass (about 3,000 kg per ha) in both the reservoir pond and the prawn grow-out pond had an ameliorating effect on the pond environment (Domingo and Visitacion, 1998). The tilapia appears to promote the growth of a good mix of phytoplankton species and prevent the deadly Vibrio bacteria from proliferating.
Tilapia, although exotic to the Philippines, is now developing into a substitute for milkfish as a common food fish. It is gaining wider and wider acceptance and can now sell at the same level with, or at an even higher price than, milkfish. The imminent popularization of the use of saline-tolerant strains will also make tilapia as a group into an all-around fish suitable for freshwater and salt water culture and for ponds, pens, cages and in limited instances even in concrete tanks.
2.1.7. Seaweeds
a. Caulerpa
Seaweeds belonging to the genus Caulerpa (Class Chlorophyceae) are all eaten fresh in many parts of the Philippines as a tangy salad that goes well with seafood. Perhaps it is not surprising that of all the marine algae, Caulerpa, specifically C. lentillifera, is the first species to have been commercially cultivated. According to Trono (1988), the culture of “lato”, as the species is know in the Visayan islands in Central Philippines, started in the island of Mactan, province of Cebu, in the early 1950s.
Its culture was attributed to its accidental introduction with some other seaweed species (most likely Enteromorpha, another green algae) in fishpond as fish food. Due to the high demand for “lato” in the markets of Cebu, which even then was already an important economic center in the south, next only to Manila, it did not take long for the brackishwater fishpond operators to start its commercial cultivation.
The technology involved is simple. Existing milkfish ponds can be used for Caulerpa farming. Cuttings are used as planting material. These are planted one meter apart. After planting the only activities involve water management and weeding. After the cuttings shall have taken roots, frequent water exchange is necessary to maintain a fresh supply of nutrients.
Fertilization is not even necessary until at an advanced stage when the algae are almost harvestable and the natural nutrients may no longer be able to support the algal biomass. This, the farmers can tell when the color of the algae appear light green or yellowish instead of its normal healthy green color. The “teabag” method of fertilizer application which involves suspending sacks of fertilizers over strategic points of the ponds with the sack only partially submerged, has been found to be sufficient.
b. Eucheuma
Where the farming of the Caulerpa was discovered accidentally and developed due to a strong local demand, the farming of Eucheuma in the Philippines was developed deliberately as a response to a strong world market demand in the 1960s. Eucheuma is also one of the marine algae used as human food but the local demand is never that high. It is as a source of the phytocolloid, carageenan that made Eucheuma have the huge global market. Carageenan has multiple uses in the food, pharmaceutical and other industries.
According to Ronquillo (1992), Eucheuma cultivation started in the late 1960s when Dr. Maxwell Doty from the University of Hawaii Department of Botany came to the Philippines to assist Marine Colloids Ltd, an American company in finding a reliable supply of the seaweed. The collection and drying of the seaweed for export was encouraged to the extent that in two years the natural stock was virtually depleted.
Upon Dr. Doty’s request, and with his assistance, the Bureau of Fisheries Research Division conducted trial farming in off Mindoro Island and various other locations. With the initial success family plots were established in Tapaan Island, Siasi, Sulu and later in Sitangkai, Sibutu Island.
However farming in earnest started only in 1973. This reportedly came after the discovery of mutant cultivar by a certain Mr. Tambalang which could double itself in volume every 20 days of culture and the strain became known as the “tambalang” variety. The tambalang was later recognized as a totally different species (and genus) and renamed Kappaphycus alvarezii in honor of Mr. Vicente Alvarez, a biologist of the BFAR Research Division who was responsible for BFAR’s early effort in farming and assisting the first group of farmers in Sulu. Although taxonomically given a new genus, its cultivation is still referred to as Eucheuma farming. The term Eucheuma farming has become a generic term for the cultivation of all the carageenophyte seaweeds in the Philippines regardless of species, and it will used as such in the rest of this document, without the usual italics.
Other species thatcontinues to be cultured is the Eucheuma denticulatum which is a good source of iota-carageenan (a soft gelling colloid). The Kappaphycus is a good source of kappa-carageenan (hard-gelling) as well as lambda-carageenan (non-gelling).
The technology is fairly simple. Cuttings of the desired seaweed species are tied to a line (either nylon monofilament or polypropylene rope) at a distance of 30 to 40 cm. Each line that ranges from 4 to 7 meters is stretched taut across two stakes driven to the sea bottom or suspended at constant depth nearer the sea surface by using polystyrene foam floats. In two to three months time the first harvest can be made. Lately Eucheuma culture inside net cages to protect the crop from grazers, has also been successfully tried (Hurtado-Ponce, 1992).
The success of Eucheuma farming in the Philippines has catapulted the country to become the world’s largest producer of carageenophyte seaweed. The nice thing about Eucheuma farming is that it is largely in the hands of small farmers. In a study by Posadas (1988), the estimated 2,747 farmers in Sibutu, province of Tawi-tawi (southernmost Philippine province) occupied a total area of only 2,005 hectares which means an average holding of 0.73 ha per farmer. In the province of Bohol, the 300 farmers in the Bien Unido municipality occupied only a total of 300 ha.
When the licensing of seaweed farming was still under the jurisdiction of the national government, an upper limit of one hectare per farm was set by a Fisheries Administrative Order, (FAO No. 108, Series of 1973) for individuals and 30 hectares for partnerships, corporations and cooperatives. (This has been superseded by the Local Government Code of 1991 which gave jurisdiction over municipal waters to local governments and which will be dealt with in greater detail in a relevant section).
c. Gracilaria
Like Caulerpa and Eucheuma the red algae Gracilaria is also eaten in the Philippines. However its biggest use is as a source of agar. The farming of Gracilaria is said to have started in Taiwan in 1962 (Trono 1988). However even earlier than that, some milkfish farmers around Manila Bay used to deliberately cultivate this seaweed in their ponds to serve as natural food for milkfish. Its commercial cultivation in the Philippines as a crop in itself must have started soon after the success of Eucheuma farming in 1973.
According to Trono (1988) Gracilaria can be cultivated in brackishwater ponds (salinity range: 20 to 28 ppt) using basically the same technique as that described for Caulerpa. Lately it has been found out that Gracilaria also grows well inside net cages set either in ponds or in open waters, (Guanzon and de Castro, 1992; de Castro and Guanzon, 1993).
There are some 17 species available in the Philippines but only two species were reportedly being gathered and used for the local manufacture of agar. But even for the two species, definitive identification has apparently not been made yet since Trono (1988) refers to the two as G. “verrucossa” and Gracilaria sp. 2. There does not seem to be a “recommended” or preferred species for culture. The available literature on its farming invariably refers only to the genus and not to the species. However Hurtado-Ponce and Pondevida (1997) found Gracilariopsis balinae a good species for cultivation because it produces strong, firm and rigid agar gels. Trial farming also shows a potentially high yield using the fixed bottom long line method similar to what is used for Eucheuma or Kappaphycus.
2.1.8. Giant Freshwater Prawn
The technology for the culture of giant freshwater prawn, Macrobrachium rosenbergii, was introduced to the Philippines during the 1970s. There were several sporadic attempts in the past to adapt the technology for its propagation but this never progressed beyond the research institution level.
In 1981 a local banker-industrialist started a large (100 ha level) commercial Macrobrachium farm in Sta. Rosa, Nueva Ecija in Central Luzon, with a hatchery in Bulacan, a province immediately north of Metro Manila. The company utilized the services of experts from Israel for the project. Their prawns were sold live in Metro Manila but only in their in-house retail chain selling exclusively products from the company’s diverse agri-business ventures. Whether it was part of their marketing strategy or limited success in farm operations was never known. Shortly after, the company diversified their operations to include tilapia. But even the diversification failed to save the first and only commercial venture in Macrobrachium production in the Philippines.
While Macrobrachium is well accepted everywhere in the Philippines, there has never been an established market and large demand for the species. Lately the establishment of many upscale restaurants in the metropolitan areas which include a growing number of Thai restaurants, appear to have spurred renewed interest for the species.
The BFAR Freshwater Fisheries Technology Center in Muñoz, Nueva Ejija now has a regularly operating Macrobrachium hatchery and is supplying seedstock to a few cooperating freshwater fishponds within the Central Luzon area. A private company has recently been allowed to import Macrobrachium juveniles from Thailand to try out its culture and eventually start its own hatchery.
2.1.9. Rabbitfish and Spadefish
The rabbitfish, Siganus spp, and the spadefish, Scatophagus argos is cultured to a limited extent in some brackishwater ponds, marine pens and cages in some parts of the Philippines, particularly in Pangasinan. Because it is a popular food fish, some fishpond operators are tempted to stock them in empty ponds because of the availability of a large number of fingerlings during certain months of the year. Being used to milkfish many are discouraged by the relatively slow growth during the first few weeks of culture.
Two species are considered faster growing than the other species. The two are S. guttatus and S. vermiculatus. Hatchery technology is well developed at least for S. guttatus. But the lack of demand from the grow-out industry has deterred its full commercialization. There has been no work done yet on the propagation of S. argos. Since both genus are known to be low-trophic level species but are higher in value than milkfish, it is likely that sometime in the near future they will be the species to watch as growers are forced to diversify.
2.1.10. Seabass, Groupers and Other Carnivorous Fish Species
Seabass had always been an occasional part of the harvest in brackishwater ponds. Naturally occurring fry often enters through the sluice gate and are considered predators of milkfish. There were also early attempts in the mid-1970s to use seabass as a predator species in a mixed sex tilapia pond to prevent overcrowding among the tilapia. However serious attempts at farming seabass in ponds as a crop in itself started only in the mid 1980s when fingerlings started to be produced in hatcheries. The demand for seabass is strong only in the Western Visayas region in Central Philippines. In Metro Manila, the species is hardly known. Due to the weak demand, the price of seabass has never risen much higher than PHP150.00 per kg. With the high cost of feeding since there is practically no “trash fish” in the Philippines (as discussed in an earlier section), the margins are slim. Thus the industry never took off.
In contrast the culture of serranid groupers, Epinephelus spp., which came in later has taken hold due to a very strong export and domestic market (mainly in upscale Chinese restaurants). Live groupers can be sold at PHP300.00 to PHP350.00 ex farm. Since it costs just as much to produce a kilogram of seabass as a kilogram of grouper it is not surprising that there is a higher interest for growing groupers even if the hatchery technology for grouper fingerling production has yet to reach the commercial stage of development. The earliest attempts were apparently made by coastal fishers whose catch of live groupers may have been rejected because they were not big enough. Rather than throwing them back to the sea, these were fattened in small cages and sold when they became big enough. Up to this time this is still being done. Thus there is a market for grouper fingerlings and post-fingerlings of all sizes from the 2-cm long “tiny” to the 15-cm long XL (Extra large).
The culture of seabass and groupers came relatively late to the Philippines compared to its neighbors like Singapore, Malaysia, Thailand and Hongkong. One possible reason for its late start is the fact the growing of seabass and grouper is dependent on a constant supply of low-cost trash fish for it to be viable. As mentioned earlier there is no trash fish as such in the Philippines since even the bycatch are eaten.
In the province of Capiz (Panay island), where both pond and cage culture of grouper is thriving, the grouper growers do not depend totally on low value sea-catch for their feeding needs. In fact in some localities the growers may depend more on tilapia (O. mossambicus) proliferating wildly in brackishwater ponds. The use of tilapia as a feed fish has also been noted in the province of Bulacan, Central Luzon (Aypa 1992), and Pangasinan (Rice and De Vera, 1998). Being overcrowded, the tilapia stock do not grow to large sizes and are not marketable. Most will be about 50 g or even less. When prawn culture was at its heyday, these tilapia would have been eradicated by using powdered teaseed cake and the dead fish collected and thrown away. With grouper culture, a market has been created for these undersized, and previously unwanted, tilapia stock. In Capiz traders dealing with this commodity has emerged to serve the needs of the grouper growers.
Just as Philippine aquaculture industry is diverse in terms of species, culture systems and ecosystems, the level of development also varies greatly from one species to another. It ranges from virtually zero technological base as is the case with spadefish to one already at the genetic manipulation stage as with the Nile tilapia. Within species the culture system could range from extensive earthen pond systems yielding only 500 kg per hectare up to highly intensive marine cages capable of harvesting as much as 50,000 kilograms in an area measuring no more than 300 m2 as is the case with milkfish. The species involved and the respective levels of technology and stage of commercialization are summarized in Table 6
