Lapulapu (Grouper) Culture

Grouper or Lapu-lapu or inid (Epinephelus spp.) is one of the most economically important cultured marine fish species in the Philippines, Australia, Japan, Hongkong, Malaysia, and Singapore.

The grouper has light yellowish, to grenish to brown body with unequal spots scattered on the head, body, and fins. There are about 40 species of groupers found in tropical waters. Two species, the E. coioides and E.malabricus, are the most preferred for culturing in ponds and cages.

According to the Southeast Asian Fisheries Development Center (SEAFDEC), the estimated income from a hectare of grouper pond is P640,000 a year. The remarkable increase in domestic and export demand of Lapulapu year after year, can make grouper culture boost the country's fish production.

Culture of grouper in net cages and brackish ponds, however, failed to reach large-scale levels due to shortage of fingerlings and trash fish as feeds. This situation drove SEAFDEC to develop strategies and techniques in making grouper culture produce optimum return and benefits for local farmers.

Culture in net cages

Choosing the site for net cages culture is the foremost consideration. The most suitable sites provide good water quality and adequate water exchange. They should also offer protection from predators, strong winds and waves.

In constructing the floating cages, one can use bamboo poles and polyethylene netting materials at 25-50 mm diameter to build 4-side panels and one bottom panel. Secure the net to the raft structure of bamboo poles using a rope. The stocking density for grouper fry (2.5-7.2 cm) in nursery cages should range from 100-150 per square meter. A 2x2x2 net can hold 400-600 fingerlings. Sort the fingerlings every week and perform stock sampling every 15 days. Hold them in nursery cages until they are about 16 cm, after which transfer to transition nets is necessary. A 5x5x5 transition net can hold 1,100 fishes. Transfer the grouper to the production net after 2-3 months.

Feed the grouper juveniles with chopped trash fish once or twice daily, in the morning or towards the evening. The recommended feeding time is when the tides are slack to minimize feeds swept away by water current.

Culture in brackish water ponds

The pond used for grouper culture is at least 1-2 meter deep. Tilapia fingerlings can serve as food for grouper juveniles. Stock adult tilapia (5,000-10,000/ha) in the pond and allow spawning for one month. The stocking density for grouper fingerlings is 5, 000/ha. Feed grouper juveniles with chopped trash fish twice a day, half of the feed requirement in the morning and the other half in the afternoon.

It is also important to have constant monitoring of water conditions (water depth - 1.0-1.3 meter; water temperature-24-31o C; salinity- 21-41 ppt; and dissolved oxygen- 4.9-9.3 ppm).

Harvest mature groupers (400-600 grams) in the morning using a drag net. Transfer the fish in holding nets for easy sorting and grading.

A farmer can harvest 4,000 pieces of lapu-lapu per hectare and sell them at P200 per kilo. The estimated net profit is P267,930 /ha for the period of eight months.

by Mary Charlotte Fresco. (Source: "Grouper Culture" published by the Southeast Asian Fisheries Development Center (SEAFDEC), Tigbauan, Iloilo); photo courtesy of alibaba.com

How to make Tofu and Soya Milk

Although the highest quality protein is found in animal products (meat, milk, eggs and fish), these products are expensive and often exceed the financial capacity of people in the developing world. The soya bean is high in nutritional value and provides a satisfactory alternative to animal products. It belongs to the grain legumes (also called pulses) and contains good quality protein, oil, vitamins (from the B-group) and minerals (iron and calcium).

The production of tofu consists of two main steps:

• the preparation of soymilk;
• the coagulation of soymilk to form curds which are pressed to form tofu cakes.

Soaking the soya beans

Soya beans are soaked in cold water overnight or in very hot water for 2 to 3 hours, using 3 to 4 cups of water for each cup of dry soya beans. When the beans split open easily and are flat on the inside, they are ready to be drained. After the water is discarded, they should be washed in clean water.

Grinding and cooking the soya beans

A grinding rock, hand mill or meat grinder can be used to grind the beans into flour. When all the beans have been ground, boiling water (for each cup of dry soya beans about 8 cups of cooking water are used) is gradually mixed to the pulp and then it is left to simmer on the fire for 20 minutes. The soymilk is stirred regularly to avoid burning.

Straining the soymilk

The cooked milk is now sieved to extract the soymilk from the pulp using a filtering cloth. It is placed into a sieve which is positioned over a pot, lined with a filtering cloth. The cloth should be made from nylon or porous material - either a flour or sugar bag can be used. The sides of the cloth are held in each hand and moved up and down to roll the pulp back and forth so it forms a ball. The cloth is twisted tightly and held over a clean container while pressure is exerted onto it to extract the milk.

Soymilk

Soymilk is easily digestible and one pint of it can provide over one half of a young child’s daily protein requirement. It can be sweetened with sugar or flavoured with chocolate, cinnamon or vanilla. Salt may also be added.

Coagulating soymilk

Soymilk is heated over a fire and boiled for 3 to 5 minutes with continuous stirring. The pot is removed from the heat and a 4% acetic acid solution is added to the soymilk and stirred constantly until a good coagulum is formed. Vinegar usually contains 4% acetic acid solution and for every litre of soymilk, 2 tablespoons of vinegar are used.

Straining the curds

When large white curds can be seen floating in a clear yellow liquid, called whey, the soymilk is completely curded and ready to be filtered through a clean cloth into a suitable mould. The same method is used here as used in straining the soymilk.

To form a block of tofu, press the cloth lined tofu with a weight for about 20 minutes which will reduce its water content by approximately 60%. This can be sliced and fried or eaten plain with salt. Alternatively, the loose curds can be scrambled in a pan with onion, tomatoes and salt and served on bread.

Preservation of soymilk and tofu

Soymilk can be stored in a bottle placed in a container of cold water. However, even in cool weather, soymilk can only be kept for a day using this method.

Unseasoned block tofu should be stored under water to prevent drying out and can be kept for 2 days in moderate temperatures.

When refrigeration is available, soymilk can be kept for up to 5 days and tofu for about 10 days.

Soymilk that sours will form into curds by natural fermentation. Providing the curds are solid and not discoloured or slimy, they can be boiled for 30 to 40 minutes to kill the bacteria and made into cheese. Tofu that becomes slightly sour can also be eaten if boiled for 20 to 30 minutes.

Source: practicalaction.org; Photo courtesy of contentanswers.com and healthgoods.com