Oyster farming

Oyster farming is suitable for small-scale and family business. Oyster or talaba is always in demand, and its culture enjoys the support of the government and various agencies.

The country exports oyster to the US, Arabian Peninsula and Japan. In 1985, we sold only 261 kg of fresh and frozen oysters to Okinawa and the Arab states. Exports of preserved oysters to the US reached 2,533 kg in 1985, valued at $6,484. Nevertheless, the local demand is greater than the supply, with fast turnover and heavy trading in the market. Oyster is sold directly to the consumers, processors and exporters.

Oyster farming also promises good returns, ranging from P1.22 to P2.43 per peso invested.

A good source of animal protein, oyster is primary cultivated for good, although it has industrial and ornamental uses. Oyster meat is delicious and is made into special dishes in hotels and restaurants. Oyster shells are used to make orminants, lime paints and poultry grit.

Oyster culture farms in the country range from 1,500 sq m to half a hectare and are usually managed by operator owners. These are found in the coasts of Cavite, Bulacan, La Union, Bataan, Cagayan, Negros and Iloilo. The Bureau of fishery and Aquatic Resources operates several oyster farms all over the country techniques, extend technical assistance to farmers and provide stock to breeders.

Oyster is usually found in shallow waters along the coast. It thrives in sea water with 0.01 to 0.05 per cent saltiness, and can be collected from stones, shells, or any hard object scattered along the coasts. Fertile eggs are released throughout the year with peaks at certain periods. Spats, or larvae that settle on the cling to hard surfaces, appear from late January to early September and also from May to August. They are then found from 30 to 40 cm below the sea level down to the ocean floor.

Species. There are at least 17 species of oysters in the country but only four are cultured commercially. These are the talabang tsinelas (slipper-shaped oyster), the pulid-pulid (palm- rooted oyster) and the kulot or curly oyster. The talabang tsinelas and the kukong kabayo are the two most commonly cultivated species, while the other grow on rocky bottoms coastal zones.

Site selection. The oyster farm site should not be subject to excessive flooding and should protected from strong current and waves. There should, however, be moderate current for good water exchange. Water should be brackish, unpolluted, and with adequate oyster food such as minutes plants and minerals or any organic particles suspended in the water. Temperature should range from 18 or 28oC and natural predators such as borers, starfishes and crabs should be minimal.

Farming methods. Productions is best when oyster is cultured above the ocean bottom.

The stake method makes use of bamboo poles to collect and grow the spats. The poles of the tolis are stuck into the soft muddy bottom a meter apart before the spawning or egg-hatching season. The spats settle at the bamboo poles 15 to 120 cm from the lowest tide. The tips of the stakes should extend out to the water surface about a meter high so that pulling the stakes is easy.

The hanging method makes use of hanging collectors or bitin to collect and grow the spats. Each collector is made of five empty oyster shells strung together with nylon rope about a meter long. They are fastened and hung on bamboo plots or rafts at 25 distance from each other. The lower end of the strings should not touch the bottom. To make the lines rigid, attach nuts shells at the end of the lines.

Each bamboo plot usually measures 1 by 20 meters, and there are about 125 plots in half a hectare. To make the plot. three bamboo poles are placed horizontally parallel to each other, spaced half a meter apart. A series of bamboo posts support each plot, staked at one meter intervals. Where the water is deep, the collectors are hung on a bamboo raft.

One roll of nylon rope can make about 180 collectors, while a kaing of empty oyster shells is needed to make 100 bitin or collectors. About 350 collectors are needed to make 100 bitins or collectors. About 350 collectors are ended to plot-43,750 for half hectare farm. Hence, about 2,570 kaings of oyster can be harvested from a half hectare farm, plus 500 additional kaings that can be gathered from the bamboo posts.

Another farming method - the "broadcast" or sabog - is effective only in the shallow water with a depth of about two meters. Oyster shells, stones, gravel and tin cans are thrown in areas where spats abound. These then will serve as settlement materials for the larvae.

Harvest. Oyster are harvested before the spawning period while the meat is still fat, full, rounded, bulging and creamy in appearance or when they reach 4-9 cm after 6 to 12 from the settling of larvae.

With the stakes method, harvesting is done by prying off the cluster of oysters from the poles underwater. Undersized oyster are broadcast and allowed to grow to marketable size so they can command a high price. The bamboo poles can be used for one to two years before being replaced. Average yield per hectare using this method is 4 to 8 tons per year.

For easier harvesting use floating rafts, constructed to fit-in-between rows of stakes or bamboo plots.

With the hanging method, harvesting is done by cutting or untying the hanging collectors from the bamboo poles. Clusters of oysters are separated by knocking them off the rope. Average yield per hectare using this method is 10 to 15 tons per year. Floating rafts produce 40 to 60 tons of oyster per hectare each year.

Postharvest. If oysters are not to be packed or transported immediately, submerge them on raft placed underwater.

Depurate or clean them by submersing in flowing clean sea water for 48 hours. Depression plants or machines may be employed to remove germs and disease causing organisms.

Oysters are sold with or without their shells, or salted into bagoong. For shipping , they are packed in sacks, keep moist, and prevented from sun exposure.

Source: dost.gov.ph, photo courtesy of pinkplate.files.wordpress.com

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