MILKFISH TECHNOLOGYChanos chanos (Forsskal,

1775 )

Members:Arellano, anthea mae

Aficionado, arianwenBotea, riza mae Abejero, dea Etang, eden

Espina, trisha rose Muchuelas, may

Milkfish farming in Indonesia, Taiwan Province of China and the Philippines started about 4-6 centuries ago. Culture methods in a variety of enclosures are constantly being improved upon. Since the 1970s, large investments have been made in the Philippines (as well as in Taiwan Province of China, Indonesia and Hawaii) in terms of infrastructure, research, credit and training in support to the milkfish industry. For example, the Southeast Asian Fisheries Development Center (SEAFDEC) Aquaculture Department (AQD) was established in Iloilo, Philippines in 1973 with a special remit to find solutions for milkfish aquaculture problems. Government agencies and fisheries institutions were also involved in a national effort to intensify milkfish farming from the mid 1970s until now. In this work, research and development on farming systems, breeding and fry production technologies was carried out. There was no attempt at genetic improvement but fry translocation and trade occurred between Indonesia, Taiwan Province of China and the Philippines and geographic variations and heterogeneity were documented. More recently, unconfirmed reports indicate that milkfish are now being cultured to fingerling or juvenile size in the South Pacific Islands and in Singapore as tuna bait. 

HISTORICAL BACKGROUND

Milkfish (Chanos chanos) is the only species in the Family Chanidae. Its distribution is restricted to either low latitude tropics or the subtropical northern hemisphere along continental shelves and around islands, where temperatures are greater than 20 °C (Red Sea and South Africa to Hawaii and the Marquesas, north to Japan and south to Victoria, Australia; and in the Eastern Pacific from San Pedro, California to the Galapagos). Adults occur in small to large schools near the coasts or around islands. They are well developed, migratory, large (up to 1.5 m and 20 kg), and mature sexually in 5 years. Milkfish only spawn in fully saline waters. The activity is most often correlated with the new or full moon phases, takes place mostly in the night and, in most regions, has one or two seasonal peaks. In the natural environment, spawning takes place near coral reefs during the warm months of the year, and populations near the equator spawn year-round. Juveniles and adults eat a wide variety of relatively soft and small food items, from microbial mats to detritus, epiphytes and zooplankton.

HABITAT AND BIOLOGY

Milkfish can reach a maximum size of 180 cm SL (male/unsexed) and 124 cm SL (female). The maximum recorded weight and age is 14.0 kg and 15 years respectively. Resilience is low, with a minimum population doubling time of 4.5 - 14 years. Its fisheries importance is highly commercial, especially in aquaculture, and it is also used in game fish as bait. It is especially valued as a food fish in Southeast Asia.

Milkfish is a heterosexual fish; hermaphrodism has not been reported. In natural spawning stocks the sex ratio is almost equal, with a slightly higher amount of females. The determination of sex is very difficult, because there are no easily identifiable morphological differences between males and females; however, the pheromone PGF2a (prostaglandin) has been found to be an effective way to identify mature male milkfish.

ONGROWING TECHNIQUES

Milkfish may be on grown in ponds, pens or cages.

Culture of milkfish in ponds may be in shallow or deep water systems.Shallow water culture is practiced mainly in Indonesia and the Philippines. Milkfish are traditionally cultured in shallow Brackish water ponds in which the growth of benthic algae is encouraged through inorganic or organic fertilization. Milkfish will survive on benthic algae alone only if the productivity of the algae exceeds the grazing rate of the fish; otherwise, supplemental commercial feeds are applied. The 'lab-lab' culture system in the Philippines is equivalent to shallow water culture in Taiwan Province of China. 'Lab-lab' is the term used in this country for the algal mat (and all micro-organisms associated with it) in the ongrowing ponds.

POND CULTURE

Brackish water ponds in the Philippines were mostly excavated from 'nipa' and mangrove areas. Shallow water pond design generally consists of several nursery and production ponds with a typical area of 2 000 m² for nursery ponds and 4 ha for production (ongrowing) ponds. Typically, ponds have a depth of 30-40 cm and are provided with independent water supplies.

The average yield of a typical integrated nursery, transition and shallow grow-out system that produces 3 crops a year is 800 kg/ha. Modified modular pond designs consisting of a series of grow-out compartments with a maximum of eight crops a year have been shown to increase

yield to a high as 2 000 kg/ha.

Deep water culture was developed in the mid 1970s in response to the decline of profitability of shallow water culture, and the limited and increasing value of land and manpower resources. Deep-water ponds provide a more stable environment and extend the grow-out period into the winter season. Most deep-water milkfish ponds have been created by converting either shallow water ponds or freshwater ponds, with a depth of 2-3 m. Production from these systems has sharply increased in Taiwan Province of China, having expanded from 23 percent of the total production in 1981 to 75 percent in 1990.

Most milkfish ponds in the Philippines and Indonesia are of the extensive and semi-intensive type, with large shallow pond units, tidal water exchange, natural food, minimal use of fertilizer alternating with commercial feeds and other inputs, and low to medium stocking rates (50 000-100 000/ha). The Taiwanese method of production, on the other hand, employs intensive stocking densities (150 000-200 000/ha). Few diseases or infestations have been recorded so far in milkfish grow-out farming in these Asian countries.

This system was introduced in the Philippines in 1979 in the Laguna Lake. At that time, the lake had a very high primary productivity, which met the nutritional needs of milkfish. Because of the low rate of input and the high rate of return, the pen culture area increased sharply from 1973 to 1983, and exceeded more than 50 percent of the total lake surface, which is 90 000 ha. As the primary production of the lake could not meet this sudden expansion of aquaculture, and feeding became necessary to meet the nutritional requirements of the cultured fish, the pen culture practices developed in lakes were later introduced into inter-tidal areas in the Philippines along coves and river estuaries as well. Pen operators stock fingerlings at 30 000-35 000/ha and provide supplemental commercial diets. However, disease spreads among culture pens and causes mass mortality. Government regulations are now being considered to maintain sustainable yields from this type of farming.

PEN CULTURE

PEN

Fish cages are smaller and more restricted enclosures that can be staked in shallow waters or set-up in deep water with appropriate floats and anchors. Cage farming of milkfish is commonly carried out in marine waters along coastal bays. Stocking rates (in the Philippines) are quite high, from 5 up to 30/m³.

CAGE CULTURE

In the past, traditional feeding practices for milkfish grow-out production have consisted of natural food ('lab-lab') or a combination of phytoplankton and macroalgae (Enteromorpha intestinales, Cladophora spp. or Chaetomorpha linnum) encouraged by fertilization. In the 1980s however, special commercial feeds for milkfish were developed and became almost exclusively used. As cage and pen culture technology proliferated in the 1990s, both in marine and inland waters, extruded milkfish feeds were further developed into floating and semi-floating forms, while sinking forms were used for pond and tank-based grow-out. Feed supplies are now manufactured commercially in the form of starters, growers and finishers, which are administered according to the production stage of the milkfish.

FEED SUPPLY

HARVESTING TECHNIQUES

Milkfish are normally harvested at sizes of 20-40 cm (about 250-500 g). There are three known methods used for harvesting milkfish:Partial harvest. Selective harvest of uniformly grown milkfish from grow-out facilities (i.e. cages, pens, ponds, tanks) using seine or gillnets, retaining the undersize fish and harvesting only the commercial sized stocks, with an average body weight of 250 g or larger.Total harvest. Complete harvest in one crop period from grow-out facilities (i.e. total draining of ponds by gravity or pump, hauling of the entire net cage structure, seining or the use of gillnets in pens). The harvest size at this stage may vary from 250-500 g.Forced harvest. Emergency harvesting, regardless of fish size or grow-out stage, which is carried out during 'fish kills' due to oxygen depletions that are attributed to algal blooms, red tide occurrence, pollution or other environmental causes.

HANDLING AND PROCESSING

200-400 g milkfish are harvested and marketed mostly fresh or chilled, whole or deboned, frozen, or processed (e.g. fresh frozen deboned, fresh frozen deboned descaled, and smoked fish deboned). In general, all marketed milkfish are produced in farms, only a few being caught from natural waters. In some countries (e.g. the Philippines) fishing for adult milkfish is officially banned in order to protect the natural broodstocks.

There are two known post-harvest processing techniques for milkfish, which are the traditional (i.e. drying, fermentation and smoking) or non-traditional methods (i.e. bottling, canning and freezing) and value-added products such as 'surimi' and deboned products as practiced in Taiwan Province of China and in the Philippines.

Regulations and standard protocols for manufacturing milkfish products exist for both domestic consumption and export, as follows:Good Manufacturing Practices (GMPs). Plant construction.Personnel hygiene and sanitation.Standard Sanitary Operating Procedures (SSOPs).HACCP compliance.

PRODUCT COSTS

Milkfish farming is a centuries-old industry in Indonesia, Taiwan Province of China and the Philippines. It has been slow to modernize and now faces challenges from competing aquaculture species and current economic realities. The domestic market is large and the export market has globally expanded. Milkfish price and personal income affect the amount of milkfish consumed in the countries of origin. Studies conducted in Taiwan Province of China and the Philippines concluded that price and income had a negative and positive elasticity coefficient, respectively.

The following are the major determining factors affecting the cost of production in milkfish:Type of culture system: costs are lowest in systems dependent only on natural food; costs increase as artificial feed is introduced; costs are highest in systems dependent totally on commercial feeds.Increasing production: with milkfish production steadily increasing and culture practices becoming more intense, a big surplus of this commodity is foreseen in the near future.Cost of feed: feeds account for 60 to 80 percent of the total production cost.Low farm-gate prices: on average, the farm-gate price for milkfish is only about USD 2.00/kg in the Philippines. As the supply of milkfish is expected to increase way above demand, fish farmers cannot demand a higher farm-gate price even though they may be spending heavily to cover production costs.Lack of post-harvest facilities for value-adding and processing.

DISEASEAGENT TYPE SYNDROME MEASURES

Nematode infestation

Capillariasp.Parasitic

nematode

Emaciated, although shows good appetite in early stage, then weakens, becomes listless, loses appetite & colour pattern darkens; fin & tail rot and skin patches/sores; faeces white & stringy/slimy; scrapes belly against bottom or may start to tremble; larval stage of parasite

located in muscle tissue & can be seen through skin, appearing either coiled up or

rod-like

Administer trichlorfon (with caution for small

fish); niclosamide, levamisole or mebendazole mixed in feed

Anchor worm

disease

Lernaea cyprinacea

Parasitic copepod

Parasite visible on skin, head embedded deep in the tissues of the host; haemorrhages and open wounds at site of infection; weight loss;

respiratory difficulties; sluggishness; red areas; ulcers; scale loss; fin damage; scraping and sometimes hanging vertically or belly up;

parasite length 5 to 22 mm

KMnO4 bath or 0.8-1.1% NaCl (KMnO4 may be

lethal to small fish at dosages required to killLernaea)

Trichodinosis

Trichodinasp.

Protozoan parasite

Slime covers skin like fog, fins clamped and denuded of tissue

250 ml/litre formalin bath for

15 min

Scolex infestationScolex

pleuronectisHelminth parasite

Infestation occurs commonly in the intestine

None stated

Cryptobia Infestation

Cryptobiasp. Protozoan parasite

Dark coloration; increased mucus

build-up; occasional appearance of skin lesions followed by scale loss; difficult or rapid breathing; reduced appetite and weight loss;

secondary bacterial infections in

advanced stage leading to pale and/or red skin

patches and skin & fin rot

Treat with formaldehyde (250

ml/litre) or 10mg/litre

malachite green; place infected fish in freshwater bath

or treat with effective

antibacterial agents

Caligus infestation Caligus longipedis Parasitic copepod

Loss of appetite; lethargic

swimming; excess mucus production; lumpy body surface

Dip infected fish in freshwater (makes

transparent parasite visible); bathe in 150 ppm

H2 02 for 30 minutes

PRODUCTION STATISTICS

Global annual aquaculture production of milkfish has increased every year since 1997; by 2005 it had risen to nearly 595 000 tonnes, with a value of almost USD 616 million. The most important producers at this time were the Philippines (289 000 tonnes), Indonesia (254 000 tonnes) and Taiwan Province of China (50 000 tonnes).

Global aquaculture production of Chanos chanos(FAO Fishery Statistic)

MARKET AND TRADE

Producers of milkfish do not usually sell fish directly to consumers, but supply them through cooperatives, brokers, dealers, collectors or wholesalers, and retailers. In general, the majority of fish products are sold in auction markets through dealers, brokers, wholesalers or cooperatives

to smaller dealers, and then retailers.

Increasingly, more of the milkfish harvest is processed into value-added forms: smoked, dried, marinated (brined, sweetened), fermented with rice, and canned or bottled in various styles

(salmon style, sardine style, Spanish style, smoked in oil, etc.). Some companies in the Philippines now produce frozen prime cuts of milkfish bellies and backs, and even of heads and

tails. Milkfish is exported in different product forms: quick-frozen, dried, canned, smoked or marinated.

The Philippines recorded an export of over 17 040 kg of milkfish products to the EU in 2002, valued at USD 58 000. While Taiwan Province of China concentrates on processed and value-

added products for export to the USA, Indonesia has strengthened its export of hatchery-reared seedstock to the rest of the Asia-Pacific region for tuna bait and for grow-out.

STATUS AND TRENDS

Successful induced spawning and larval rearing of milkfish were first accomplished at SEAFDEC/AQD in 1976-1978. The first generation cycle of milkfish in captivity was completed at AQD when the offspring of a wild female induced to spawn in 1978 in turn spawned in 1983. Since then, milkfish have matured and spawned in floating cages, ponds, and concrete tanks in the Philippines, Taiwan Province of China, Hawaii, and Indonesia. Since the successful completion of larval rearing technology in 1984, fry production has increased significantly, which has not only provided milkfish farmers in Taiwan Province of China with ample supply but also opened an export market to neighbouring countries.

To date no substantial technical and scientific research has been documented from major milkfish producing countries other than the policy and management related research being conducted by the WorldFish Center, the SEAFDEC Aquaculture Department and the Bureau of Agricultural Research and BFAR of the Philippine Department of Agriculture.

Research and Development

Taiwan Province of China, however, has recently developed an improved strain of milkfish through selective breeding process resulting in a golden coloured F1 pioneered by a

private farmer; this would accordingly command a better price than the original silvery coloured strain, once introduced in the market.

Development perspectives

The development of more efficient culture systems has resulted in higher milkfish production, which continues to increase.

Diversification of aquaculture in Taiwan Province of China, however, has paved the way for prioritizing other high valued commercial marine species of fish, which has affected the growth

of the milkfish industry.

Based on current trends, production in the Philippines (which has expanded its traditional land-based milkfish farming from Brackish water fishponds to marine cages in coastal

communities through the establishments of mariculture parks) is expected to rise from 289 000 tonnes in 2005 to 369 000 tonnes in 2010. Assuming that the population of the

Philippines reached 84 million by the year 2005, at per capita milkfish consumption of 2.5 kg/yr the total milkfish requirement would reach 210 000 tonnes. With the actual milkfish production recorded as of 289 000 tonnes in 2005, there would have been an estimated supply surplus of 79 000 tonnes.In Indonesia backyard hatchery production of milkfish

seeds has become a rural industry at the village level. The majority of these hatcheries have further shifted to fry production of high-value species of marine finfish.

Market perspectives

Marketing of milkfish products contribute a lot to the sustainability of the industry in the major milkfish producing countries - Indonesia with its seed production exports, Taiwan Province of China with value-added milkfish products and the Philippines with whole fresh and processed

products both for domestic and export markets.

The General Agreement on Tariffs and Trade GATT/WTO impositions of trade restrictions and the EU/US bio-safety and quality control standards are considerably affecting the producing

countries and are foreseen to be an added burden among production costs.

Although HACCP from farm to product processing are now strictly observed (for both domestic and export markets) in the major producing countries, farmers and processors view this as

another trade barrier that has been set by the importing industrialized countries.

Main issues

Producers and consumers have benefited from new technology; however, broodstock technology is still unreliable and fry supply is not fully controlled.

Milkfish will remain a traditional foodfish in the Philippines, Indonesia and Taiwan Province of China; however, the younger generation tends to avoid eating milkfish because of their bony flesh;

thus new markets will be difficult to create.High land values and the relatively low value of milkfish mean that farmers will have to introduce

new technology to increase unit productivity.Milkfish aquaculture will no longer rely only on natural productivity; the use of formulated feed

will become the norm.More hatcheries, especially in Indonesia and Taiwan Province of China, are expected to come on-

stream. This, and improved spawning technology, is expected to decrease fry costs.New product forms need to be developed, advertised and marketed.

As mass production of milkfish fry in hatcheries expands, more fingerlings will become available for the baitfish industry.

Further research and development on the marketing and processing of milkfish is desirable.

The main issues in milkfish farming can be summarized as follows:

RESPONSIBLE AQUACULURE PRACTICES

Due to global market demand, major milkfish producing countries have recently been promoting management practices that address food quality and safety issues. At the farm

level for example, the Philippines complies with the minimum aquaculture HACCP requirements, from hatchery production to harvest, before milkfish products are processed for export. Taiwan Province of China has introduced product eco-labelling in order to export

quality branded processed milkfish products, while Indonesia ensures the quality of milkfish fry when exporting to neighbouring Asian countries and accompanies them with health certificates. Traceability in the use of antibiotics and unregulated drugs is already

strictly imposed in these countries.

REFERENES

Agbayani, R. and Lopez, N.A. 1989. Economic analysis of an integrated milkfish broodstock and hatchery operation as a public enterprise. Aquaculture, 99:235-248.Ahmed, M., Magnayon-Umali, G.A., Valmonte-Santos, R.A., Toledo, J., Lopez, N. and Torres, F.J. 2001. Bangus fry resource assessment in the Philippines. ICLARM Technical Report, 58. 38 pp.Anonymous. 1997. What is multi-species backyard hatchery technology? Newsletter of the Gondol Research Station for Coastal Fisheries, Central Research Institute of Fisheries, 3:1-8.Bagarinao, T.U. 1991. Biology of milkfish (Chanos chanos Forsskal). Aquaculture Department Southeast Asian Fisheries Development Center, Tigbauan, Iloilo, Philippines. 94 pp.Bagarinao, T.U. 1999. Ecology and farming of milkfish. SEAFDEC Aquaculture Department, Tigbauan, Iloilo, Philippines. 171 pp.Baliao, D.D., de los Santos, M.A. and Franco, N.M. 1999. The modular method: milkfish pond culture. Aquaculture Extension Manual No. 25. SEAFDEC Aquaculture Department, Tigbauan, Iloilo, Philippines. 128 pp.Chang, S.L., Su, M.S. and Liao, I.C. 1993. Milkfish fry production in Taiwan. Tungkang Marine Laboratory Conference Proceedings, 3:157-171.Corre, V.L. Jr., Janeo, R.L., Dureza, V.A. and Edra, R.B. 2001. Milkfish broodstock management and fry production in tanks. Philippine Council for Aquatic and Marine Research and Development, Los Baños, Laguna and University of the Philippines in the Visayas, Miag-ao, Iloilo, Philippines. 38 pp.Gordon S.M. and Hong, L.-Q. 1986. Biology. In: C.-S. Lee, M.S. Gordon & W.O. Watanabe (eds.), Aquaculture of milkfish (Chanos chanos): state of the art. The Oceanic Institute. Makapuu Point, Waimanalo, Hawaii 96795, USA. 284 pp.Israel, D. C. 2000. The milkfish broodstock-hatchery research and development program and industry: a policy study. Philippine Institute for Development Studies. Makati City, Philippines. 63 pp.Kumagai, S., Bagarinao, T. and Unggui, A. 1980. A study on the milkfish fry fishing gears in Panay Island, Philippines. SEAFDEC Technical Report, 6:1-34.Lee, C-S. 1995. Aquaculture of milkfish. Tungkang Marine Laboratory Aquaculture Series, 1:57-83.Lopez, N.A., Vicaldo, Ma. V. and Fadriquela, J. 1986. The Philippine National Bangus Breeding Program. In: J.L. Maclean, L.B. Dizon & L.V. Hosillos (eds.), Proceedings of the First Asian Fisheries Forum, 13-15 May 1986, pp. 76-78. Asian Fisheries Society, Manila, Philippines.Schuster, W.H. 1960: Synopsis of biological data on milkfish Chanos chanos (Forsskal, 1775). FAO Fisheries Biology Synopsis, 4. 60 pp.Villaluz, A.C., Villaver, W.R. and Salde, R.J. 1982. Milkfish fry and fingerling industry of the Philippines: methods and practices. SEAFDEC Technical Report, 9. 84 pp.Villaluz, A.C., Villaver, W.R. and Salde, R.J. 1983. Milkfish fry and fingerling industry of the Philippines: methods and practices. SEAFDEC Technical Report, 9 (2nd Edition). 81 pp.

BIBLIOGRAPHY