PART III BACKGROUND PAPERS (Contd.)

SHRIMP HATCHERY TECHNOLOGY IN EAST JAVA

NYAN TAW
FAO-UNDP INS/85/009 Shrimp Culture Development Project, Jepara, Central Java.

ABSTRACT

In East Java, there are at present 55 shrimp hatcheries registered for development of which 29 commercial hatcheries are in full operation. The production capacity of these hatcheries ranges from 10 to 100 million PL's per annum. Locally, these hatcheries are categorized either as “Hawaii” or “Taiwan” system. The distinct difference is that those categorized as “Hawaii” use ambient temperature and clear water (maintained by high exchange rate) while the latter maintains a high temperature (up to 35°C) with the use of heaters while the water is allowed to become rather murky (due to very little or no water exchange). Those hatcheries that from the very start were intended to operate using the Hawaii system tend to be well engineered and are characterized by having a large reservoir. Those using the Taiwan system might have a central heating system either using steam from oil-fired boilers or electric immersion heaters. Some hatcheries might have started using Taiwan system only later to convert to Hawaii system operationally without revising the basic design. Others may use elements of both depending on the technicians' biases. All use an array of antibiotics for prophylaxis and various artificial larval feed in addition to diatoms (mainly Skeletonema) and brine shrimp.

1. INTRODUCTION

According to the Directorate General of Fisheries, there were 80 hatcheries registered for development as of March 1987, in Indonesia, with a combined total shrimp postlarvae production capacity estimated at 2.55 billion per annum. Since then shrimp hatchery development has been very rapid. In East Java, as of October 1988, the total number of hatcheries registered for development was 55 of which 18 hatcheries, with a PL production capacity of between 10–100 million per annum, were in operation in Situbondo District alone (Situbondo District Fisheries Office, 1988). During May 1989, an additional 11 hatcheries were officially opened and in operation in the region. With all the hatcheries in full operation the number of postlarvae produced from the region would be tremendous. It is estimated that once all the hatcheries are in operation, the total PL production could be about 2.0 billion per annum in East Java alone.

At present, due to a very rapid development of hatcheries in the region, the competitive nature of the business is evident. To be able to stay in business, technical advantage to reduce the production cost and at the same time produce high quality PL is a necessity. Each hatchery therefore tries to portray the superiority of the system used often with conflicting claims. Thus in East Java today, a hatchery is categorized either as “Taiwan” or “Hawaii” system. This paper is an attempt to clarify the state of shrimp hatchery operation technology in the region.

2. HATCHERY OPERATION

In East Java, of the 55 hatcheries presently registered for development, 29 commercial hatcheries (PPUW and Subcentre, East Java not included) are in full operation as of May 1989. The PL production capacity of the hatcheries vary between 10 and 100 million per annum. Hatchery operation technology in the region differs from one hatchery to another. This is mainly due to the locality, topography, environmental condition, availability of fund and the technology used by the consultant or the technician concerned. Distinct categorization is possible in some of the hatcheries, i.e., “Taiwan” or “Hawaii” as claimed while some, especially those run by locally trained technicians, defy definite classification, since they could be using elements from different systems depending upon the experience or biases of the technician in charge. A summary of basic facilities and hatchery management technology of the systems are given in Table 1 and 2.

2.1 Hawaii System

The hatchery operation system which is locally known as Hawaii, evolved from the technology introduced by the Indonesian Government's ADB-assisted Brackishwater Aquaculture Development Project, No. 1 Hatchery in Situbondo, East Java. The hatchery was set up and started by the Hawaii-based consulting company, Aquatic Farms Ltd. (AFL). The hatchery was inaugurated on May 1987. During the first year of operation it is reported to have exceeded its production target of 40 million shrimp fry by 5 million.

One distinct feature is that the rectangular larval tanks have V- bottoms. The original AFL-designed hatchery used fiberglass larval tanks. Later hatcheries following the AFL design shifted to the much cheaper concrete tanks but still following the same shape. Broodstock are maintained in separate tanks in total darkness with special feed. Small fiberglass tanks are used for spawning. After spawning, the eggs are collected, disinfected and transferred to 25-liter tubular hatching jar with conical bottoms made either of plastic bags or fibreglass. Intense artificial light and strong aeration is provided during the hatching process.

Upon hatching the nauplii are then transferred to the larval rearing tanks. Normally the nauplii stocking density is between 100 and 150 nauplii per litre. In the larval tanks aeration is provided from pipes laid at the V-shaped bottom along the length of the tank. The tanks are covered with canvas through out the rearing period. Upon reaching PL-1 to PL-5 the postlarvae are then transferred to larger postlarval rearing tanks. The tanks are made of concrete with flat bottom. The postlarvae are reared until PL-20, at which stage it is ready for sale. A production of between 10 and 40 postlarvae per litre is achieved with this system.

The water utilized is sand-filtered and treated with chemicals such as NaOCl (5–10 ppm) and EDTA (4–8 ppm). Daily percentage exchange of water for larvae (zoea to mysis) in the larval rearing tank is low (20–30%) and for postlarvae percentage of water exchange is increased to between 40 and 70%. Salinity of above 30 ppt is maintained for the larval rearing water. The temperature of water is kept at between 30 and 32 degree centigrade without the use of heaters. The system relies on a large reservoir (150–400 mt). Each hatchery has at least two reservoirs. For prophylaxis, different chemicals are used, such as chloramphenicol (3–4 ppm); Furazolidone (1–2 ppm); Treflan (0.05 ppm); Malachite-green (0.01–0.1 ppm); formalin (10–25 ppm).

For artificial feed, commercially prepared products from Japan, USA and Taiwan are used both for larvae and postlarvae. However, for broodstock and spawners, feed such as crab, mussel or squid meat are used. Artemia nauplii are given from mysis through PL. According to the technicians, in some cases the nauplii are weakened or killed with warm water before feeding. The Artemia cysts are rarely decapsulated.

Micro-algal food consists only of the diatoms, Skeletonema sp. and Chaetoceros sp. The BADP hatchery has a laboratory with good facilities for isolation, pure culture maintainance, and scaleup. However, the technicians take advantage of the natural occurrence of an almost pure culture of Skeletonema sp. at Tanjung Perak, Surabaya harbor by using this natural stock as starter for mass culture. Algal cell count is controlled in feeding. At present some hatcheries are trying the microflagellate, Tetraselmis sp. provided by the East Java shrimp culture development subcentre.

2.2 Taiwan System

The Taiwan hatchery operation technology was introduced by Taiwanese technicians who were brought in by private enterprises to plan, implement and operate on their behalf. The development of the Taiwan system has been recent (1987) and a few hatcheries are still in the implementation stage in the region.

The system utilizes large larval and postlarval rearing tanks (20–60 mt). The facilities and operation technology of the system is simple. The rearing tanks (broodstock, spawning, larval and postlarval) are almost of the same size and design. The size depends on the production capacity of the hatchery. The tanks are usually square or slightly rectangular with a depth of between 1.2 and 1.8 meter. From spawning to larval rearing up to postlarvae the same tank is utilized. Stocking density of nauplii is not determined, but the emphasis is on the number of spawners used. The number of spawners used depends on the technician.

The aeration for the tanks are provided by plastic hoses hanging from the top of tanks supported by ropes or wires secured across the tank. The tanks are covered with canvas during the nauplii to early PL stage. But at a later postlarval stage (PL) the tanks are uncovered. The postlarvae are reared until about PL-20. Normally a 40 cubic meter capacity rearing tank can produce as much as 3.0 million of PL-20 fry. In some hatcheries the PL-20 are nursed in large (75–100 mt) nursery tanks (shallow with sandy bottom) before selling or stocking in ponds.

The water utilized is sand-filtered but is not chlorinated. However, in some hatcheries, the filtered seawater is passed through activated carbon or FeO. The filters are always overhead and the filtered water are stored in a small (48–75 mt) over head tank. A hatchery would have at least two sets of such filter and reservoir. Larval rearing water is seldom changed. But according to technicians a small percentage (5–10%) of water is change daily. High salinity (above 30 ppt) water is used for larval rearing. Most of the hatcheries use heaters to maintain a high temperature of up to 34.0°C. Various powders are used during the larval rearing process but the exact nature cannot be determined and the Taiwanese technicians are often secretive or unable to communicate in Indonesian or English. These powders are believed to be different types of antibiotics.

Commercially prepared feeds from Taiwan are mainly used as artificial feed for larvae and postlarvae. Artemia nauplii is also essential as feed for mysis through postlarvae. However during the early larval stage from zoea through mysis, Skeletonema is used. The success of the Taiwan system in East Java is largely due to the presence of naturally dominant (over 90%) Skeletonema sp. at Tanjung Perak, Surabaya. The situation is similar to that of Kaoshiung Habour in Taiwan (Liao, et al, 1983). The Skeletonema sp. stock is routinely collected from the area by plankton net and transported to the hatchery for mass culture. The amount of algae given appears to be in excess. A laboratory for maintaining pure algal stock or scale-up culture is not provided in the Taiwan hatcheries.

2.3 Mixed System

Many of the hatcheries, especially those run by locally trained technicians mainly at BBAP Jepara, cannot be categorized under either system. Before the coming of the Taiwanese technicians, the only technology available was that from BBAP Jepara. This was introduced through the UPPUW in Pasir Putih, Situbondo District. With the recent introduction of the Hawaii and Taiwan systems, the hatchery technicians in the region modified their practice and tried to apply what each felt was the best of either systems.

Generally, the mixed system uses the same procedure in the management of broodstock through spawning to larvae and postlarvae rearing as the Taiwan system. Chemicals and antibiotics are routinely used in water management and disease control. The rearing tanks are bigger than those of the Hawaii system but smaller than those of the Taiwan system. A laboratory is maintained to monitor the water and larval conditions. For feed the system also relies on commercially prepared feeds and Artemia nauplii. Algal feed consist of Skeletonema sp. with starter stock routinely collected from Tanjung Perak for mass culture. A few hatcheries have a laboratory for scale-up culture and for maintaining pure algal stock.

Unlike the Hawaii system which relies on large water reservoirs, these hatcheries have small or medium size water reservoirs. At times some of the larval tanks are used as water reservoirs. The stocking density of nauplii is slightly more (100–200 N/litre) and the production is at times higher (10–50 N/litre) than the Hawaii but lower than the Taiwan system. Compared to Hawaii system there appears to be a higher risk involved most probably due to the instability of the technique. In some cases, some hatcheries operate both systems (Hawaii and Taiwan) using the same facilities at different times, with different technician.

3. ECONOMICS

The economics of the different hatchery systems, capital investment and operation cost, are difficult to assess. According to information acquired from the hatcheries, the capital investment amounts to between Rp. 700 million and Rp. 1,000 million for a Hawaii system hatchery. A large hatchery costing Rp. 1,000 million is expected to produce 75 million PL's per year. However, a Taiwan system hatchery, with an investment of Rp. 1,000 million is expected to produce 100 million PL's per annum.

According to the hatchery managers the cost to produce one shrimp fry up to PL-20 is between Rp.6 and Rp. 9 (includes both capital and operation cost.). The revenue from the sale of PL was high (Rp. 20-Rp. 26/piece) about a year ago. However, the price of PL's has dropped drastically in the past few months. In July, 1989 the PL price per piece dropped to Rp. 9-Rp. 15. As of this writing (September, 1989) the price per fry ranged between Rp. 6 and Rp. 15.

The price of fry from a Hawaii system hatchery and a Taiwan system hatchery is not the same. Shrimp farmers reportedly prefer fry produced by the Hawaii system hatchery to those of Taiwan system hatchery. According to one shrimp farmer, survival in the pond is higher for fry coming from the Hawaii system hatchery. According to the farmer's data a survival of approximately 85 and 60 per cent was achieved from fry brought from Hawaii and Taiwan system hatcheries, respectively. At present while the price per fry from a Hawaii system hatchery is sold at Rp. 11-Rp. 15, those from the Taiwan system hatchery can get only between Rp. 6-Rp. 8. Due to this disparity many hatcheries try to get a higher price for their postlarvae by identifying the system used in their hatchery.

4. DISCUSSION

All the three hatchery systems could be considered as intermediate system (Japanese + Galveston) (AQUACOP, 1985). But adaptation and modification have been made to suit the local conditions.

The major differences in investment between what is locally known as Hawaii and Taiwan systems could be on the capital investment. Hawaii system relies on very large ground level reservoirs where a high percentage of the investment would have to be used. The investment on reservoirs would be much less in the case of Taiwan system. Furthermore the design and structure of the Hawaii is more complex than the simple Taiwanese design.

In hatchery management the Hawaii system appears systematic with the parameters controlled at every stage of culture, whereas the Taiwan system appears to rely more on the skill of the technicians. The Taiwan system uses a large number of spawners, and starts with an unknown number of nauplii. It appears that the Taiwan system strategy is based on mass stocking of nauplii though mass spawning by large number of spawners. According to information acquired, production is known to be unpredictable. A very large production could be achieved from a tank and but total loss could also be experienced at times.

Hawaii system relies on pure culture of algae, Skeletonema sp. and Chaetoceros sp. isolated and maintained in a laboratory. However, Taiwan system greatly depends on the natural stock of Skeletonema. The success of Taiwan system in the region is mainly due to the naturally occuring Skeletonema sp. at Tanjung Perak at Surabaya.

At present, most probably due to the higher price of PL produced from the Hawaii system hatchery, a few hatcheries are identifying their hatchery as such. At the same time there are still some entrepreneurs who prefer the Taiwan system as they think in terms of high production capacity.

The hatcheries using these management systems are at present exceeding the required production of postlarvae for the existing intensive shrimp farms in the region. This could be clearly seen by the recent decline in the price of PL's at least in the region. But given time for intensive shrimp farms to develop, the future of hatcheries appears to be bright, considering the rapid development of intensive shrimp farms (2,910.5 hectares) in Banyuwangi and Situbondo Districts (East Java Provincial Fisheries Office, 1988).

5. REFERENCES

AQUACOP.1985. Overview of penaeid culture research: Impact on commercial culture activities. In Proceeding of the First International Conference on the Culture of Penaeid Prawns/Shrimps, SEAFDEC Aquaculture Department, Iloilo City, Philippines.

District Fisheries Office, Situbondo, East Java.1988. List of shrimp hatcheries registered for development in Situbondo District, 6 October, 1988.

Provincial Fisheries Office, Situbondo, East Java. 1988. List of shrimp farms registered for development in East Java Province, December, 1988.

ACKNOWLEDGEMENTS

I would like to sincerely thank Mr. Wilfredo G. Yap, CTA of the present Project for his encouragement and interest in the study. Thanks are also due to Ir. Santosa Djoenadi, Head of Subcentre East Java and members of the Subcentre, specially Ir. Gatot Pitoyo, for their help in many ways.

Table 1. Basic facilities of East Java shrimp hatcheries' systems.

Table 2. Basic hatchery management systems of East Java.

SOME CONSIDERATION IN SHRIMP CULTURE OPERATION IN INDONESIA TAMBAKS

Bambang S. Ranoemihardjo
Brackishwater Aquaculture Development Centre, Jepara, Central Java

ABSTRACT

Three levels of shrimp culture are identified, namely: 1) low-level or traditional, 2) medium-level or semi-intensive and 3) advance-level or intensive. Their relative merits and demerits are discussed. While traditional shrimp culture requires low capitalization and operating cost and produces large shrimps which commands high prices, its total production is low and management and control is difficult.

Meanwhile advance or intensive shrimp culture may be able to produce at very high level but the shrimps produced are relatively small while the capitalization and operating costs are very high. It appears that with the present low shrimp price situation, the best approach is the medium level or semi-intensive culture because the operational costs is not as high as for intensive culture while the shrimps at harvest are fairly large and commands a high price.

1. INTRODUCTION

At present many tambak operators already understand and have experience in the culture of black tiger shrimps (P. monodon) in tambaks. Actually not only tambak operators have ventured into rehabilitating old ponds or developing new ones for shrimp culture, but even small and large entrepreneurs from other business activities, have jumped into such ventures. Ever since the government started to consider shrimp as a prime nonoil export commodity from the fisheries subsector, shrimp culture progressed rapidly. This was also one way for the government to prevent the displacement of many people dependent on shrimps after the Presidential Decree banning trawl fisheries was implemented in 1980, and at the same time direct the shrimp production activity from capture to culture. The impact of this is the increase in the area developed for tambak as can be seen in the statistical data. (Tables 1 and 2). It is hoped that the government shall continue to push for increased production through aquaculture in a manner which shall be environmentally sound.

In the beginning shrimp was only a side-product in tambaks, this became a primary product only in the mid-1980's when shrimp culture expanded rapidly. In order to stimulate and increase shrimp production the government, among others, launched the INTAM programme which is more or less based on the success of similar schemes for other agricultural commodity such as rice.

INTAM programme involves intensification in existing tambaks. In principle tambak intensification is to be carried out by applying the Sapta Usaha Pertambakan, which consists of the following:

1. Tambak rehabilitation/improvement
2. Water supply and management
3. Pond bottom preparation
4. Stocking with good quality fry and feeding
5. Pest and disease control
6. Harvest and marketing
7. Operations management

The extent of application of Sapta Usaha Pertambakan depends very much on the level of tambak culture technology which is known to consist of three levels namely low, medium and advanced level.

2. SHRIMP CULTURE TECHNOLOGY LEVEL

Aside from having two culture systems based on species stocked, that is shrimp monoculture or shrimp/milkfish polyculture, there are three levels of shrimp culture technology as mentioned earlier. The three levels may be more clearly defined as follows:

1. Low level or traditional
2. Medium level or semi-intensive; and
3. Advanced level or intensive.

Each level has its own characteristics and are discussed below.

2.1 Low Level Shrimp Culture

Traditional shrimp culture operation uses very low level technology in which the ponds are not systematically designed and laid out and use only one sluice gate to both supply and drain water. The pond bottom is provided with canals which could be from 16% to 20% of the relatively large pond areas.

The tambak farmers prepare the pond by merely drying and scooping mud out of the pond bottom canal which is plastered on the dike. The sluice gate is repaired to some extent and filters consisting of bamboo screens are installed.

Shrimp fry usually comes from the wild and are merely allowed to enter with the tide. Usually these are mixed with fry of other species including fish, with the amount of fry entering beyond the farmers' control. This can be done several times so that there is really no way of knowing the actual number coming in.

The shrimps are harvested using a bamboo-screen barrier trap or more often by the use of a posongan or trap set at the mouth of the sluice gate. A bag net may also be set at the sluice gate itself and lighted with a kerosene lamp at night. Often large lift nets may also be used. The culture period is not set because the size of the shrimp fry coming in is not uniform. The harvest is low and ranges only from 300 to 800 kg/ha per year.

The government is trying to improve the production level in these traditional ponds by encouraging pond improvements and the controlled stocking even at a low density of 15,000 to 20,000 fry/ha/crop. This may also be done in polyculture with milkfish and at the same time take advantage of existing natural food which generally is abundant.

2.2 Medium Level Shrimp Culture

The pond compartments in a medium level tambak are generally already constructed following a proper lay-out and are no longer as wide as traditional ponds. Usually, peripheral pond bottom canals are still provided and cover about 32% to 40% of the tambak area. Each pond is already provided with 2 sluice gates, one for supply and another for drainage so that the dirty water from the pond does not get mixed up with the clean water. The water generally is deeper than that of traditional ponds and can be maintained at 100 cm. Pond preparation consists of drying of the pond bottom, and fertilization with organic and inorganic at the required level in order to stimulate the growth of natural food. Pond pest control is practiced with the use of pesticides in order to eliminate predators and competitors.

Shrimps are stocked at a set density using either natural fry or hatchery fry although natural fry are often very variable in sizes since they do not necessarily come from one spawning unlike hatchery fry. The stocking density is about 10 fry/m² and the culture period about 120 days. The harvest can reach up to 1,500 kg/ha/year.

Just like traditional tambak, semi-intensive tambak may also practice polyculture of shrimps with milkfish so that the natural food can be fully utilized and over-all production is increased. The government is also recommending the improvement of semi-intensive culture in order to increase their production through the INTAM programme.

2.3 Advanced Shrimp Culture Practice

Advanced shrimp culture tambaks have very well designed ponds which are already almost ideal and have separate supply and drain gates. However many also use PVC pipes instead of sluice gates for bringing in new water using pumps as well as for draining. With this method each pond compartment can be filled or drained at any time, meaning the water can already be managed properly. The ponds are also relatively small for easier control.

The ponds are prepared according to standard practices, which include complete drying of pond bottom, liming to control soil pH and pesticide application to eliminate predators and competitors. In addition, the water quality is maintained in good condition with the use of paddlewheels or other aeration system and with the use of certain chemicals.

The fry used in intensive ponds come from the hatchery and are stocked at a density of 50 fry/m² or higher. In this type of culture, fertilization is no longer practiced since it relies completely on artificial feed. Culture duration is 120 days. Harvest is done on a total basis by draining the ponds and reaches about 3,000 kg/ha per crop or more. In intensive culture, polyculture with milkfish is no longer practiced.

3. ADVANTAGES AND DISADVANTAGES OF THE VARIOUS SYSTEMS

As with all types of activities, there are always advantages and disadvantages in each system or level of shrimp culture. This is the subject of the succeeding discussion.

3.1 Traditional Level

The advantages of the traditional system of shrimp culture are as follows:

• The operational cost is lower, since it consists only of pond preparation costs, that is scooping mud out of the canals, repair the sluice gates and dike and installation of bamboo screens. The fry do not cost anything since these merely come in with the tide. During the rearing period, no artificial feed is required because the natural food is sufficient.
• The size of shrimps at harvest are bigger and commands a higher price. The culture period is not too long because generally the wild fry coming are already big, although variable in size. Harvest can be done with bamboo traps or with lift nets and does not require too many people.

The disadvantages are as follows:

• The total harvest and the income it provides is very low because the survival is very low. This is because the pests are not controlled.
• Very large ponds, most of which are irregular in shape, makes it very difficult to manage the tambak.

3.2 Medium Level

The advantages of the medium level shrimp culture are as follows:

• The ponds are relatively well-designed and small in size and are easy to operate and manage.
• The harvest size is relatively big and can command a relatively high price also. This is because the survival rate is relatively high although the density may not be very high. Pesticides are already used to control predators and competitors.
• The operational cost is relatively low because the amount needed for fry purchase is not too much, and the amount of feed required not too high because it is merely supplemental to the natural food which has been stimulated to grow by fertilization.

The disadvantages of this system is that the total harvest is still low relative the area because the stocking density is low.

3.3 Advanced Level

The advantages of this system are:

• The ponds are well designed and are small in size and therefore easy to manage.
• The production is high because of high stocking density and high survival rate due to the application of pesticides and other chemicals for maintaining water quality.

The disadvantages are:

• The size at harvest is small so that the price is also not too high.
• The operational costs is very high because of the high requirements for fry, feeds, pesticides and other chemicals. Furthermore it also requires additional costs for buying, operating and maintaining various machines such as pumps and paddlewheels, all of which use either electrical or diesel power.

4. CONCLUSION

Following the development of shrimp culture in Indonesia, it appears that the medium level technology will develop faster and will be applied by more tambak operators. This is because of its relatively lower operational costs while yielding larger shrimps which command higher prices. This option is based on the present situation where the shrimp price still continues to fall and has not stabilized, so that in order to make profit the shrimps harvested should be big in size.

While the traditional tambak may be able to harvest larger shrimps, its total production relative to the area is too low so that it may still not be profitable. Meanwhile advanced level shrimp culture can be applied only by those with adequate financing because of the high development and operational costs. While the total production may be high the size at harvest is not big enough.

For sure, by selecting the proper approach, the shrimp culture industry in Indonesia can become successful. With the fulfilment of the government programme in fisheries through the Sapta Usaha Pertambakan it will not be long before Indonesia will become a very important shrimp producing country.

5. REFERENCES

Martosubroto, P. dan Hardjono. 1989 Environmentally oriented shrimp culture development (in Indonesian). In Primadona, Informasi Industri dan Usaha Udang, May 1989, pp. 12–17.

Ranoemihardjo, B.S. 1989 Introducing shrimp culture (in Indonesian). In Primadona, Informasi Industri dan Usaha Udang, January 1989, pp. 16–20.

Table 1. Culture area (in hectare) according to culture system, 1979–1986

Table 2. Tambak production according to species, 1979–1986.

* Including East Timor without species breakdown.

FRESH ANCHOVIES (STOLEPHORUS SP.) AS AN ALTERNATIVE SUPPLEMENTAL FEED IN
P. MONODON NURSERY PONDS

Iin S. Djunaidah, Kasnadi, Yahya and Sugianto
Brackishwater Aquaculture Development Centre, Jepara, Central Java

ABSTRACT

The use of fresh anchovies as nursery feed for P.monodon fry was compared with pellets alone or in combination with pellets. The experiments were conducted in 15×30 m ponds for a period of 4 weeks using PL-5 to PL-8 fry from the BBAP hatchery. Limited number of ponds prevented the testing of all three feeding regimes simultaneously so that those fed fresh anchovies only were conducted at a different times from those fed pellets only and pellets plus fresh anchovies. The results show that in terms of growth the differences were not remarkable since the final length/weight attained were 4.1 cm/432.5 mg; 3.9 cm/406.5 mg; 4.2 cm/395 mg for those fed fresh anchovies, pellets only and pellets plus fresh anchovies respectively. However the survival rates were very much higher for those fed only fresh anchovies at 77.5% and 85.7% against 23.5% and 59.6% for those fed pellets only and pellets plus fresh anchovies respectively.

1. INTRODUCTION

In raising the production level of shrimps the use of prime quality fry is required. Good quality fry can be distinguished by its dark coloration, slender body, and a quick reaction to physical stimulus. In the field it may also be added that the fry stocked are capable of growing properly and are resistant to environmental fluctuations.

With that in mind, an experiment was conducted on the rearing of shrimp postlarvae from the hatchery in earthern ponds in order to produce older and larger fry. It was expected that by stocking them at a larger size in the grow-out ponds, the mortality rate during the initial month can be reduced.

In connection with this earthern pond nursery experiment, the use of fresh ikan teri or anchovies (Stolephorus sp.) was tested, since this fish species is easily obtainable in the market. In order to give an idea on its merits as a supplemental feed, the results were compared with other types of feed.

2. MATERIALS AND METHOD

2.1. Experimental Pond

The experiments were conducted in the BBAP J-series earthern ponds measuring 15×30 m.

2.2. Experimental Animals

The experimental animals were PL 5–8 P. monodon fry from the BBAP hatchery.

2.3. Preparation

Pond preparation consisted of pond bottom drying, pest eradication and fertilization. Drying of pond bottom was done for 7 days and was followed with pest eradication using 10 ppm saponin. In order to ascertain that the correct type of natural food (i.e. copepods and diatoms) will be available, organic fertilizer in the form of cow manure was applied at the rate of 0.8 kg/m² followed by inorganic fertilizers (Urea and TSP).

The organic fertilizers were spread all over the bottom of the ponds when these were still dry. Water was then allowed to enter to a depth of 5 cm and was maintained for 3 days to allow the organic matter to decompose and mineralize. After this period, the water was increased to the maximum level, and the inorganic fertilizers, dissolved in water, applied.

2.4 Stocking

In order to prevent stress, the shrimp fry were stocked late in the afternoon when the temperature of the rearing water was not too high. The basins containing the fry were allowed to float in the pond water for about 15 to 30 minutes in order for its temperature to equilibriate with that of the pond water. Only then were the basins slowly tipped to allow the fry to swim out by themselves.

2.5. Water Management

In order to maintain good water quality, the nursery pond water was changed at the rate of 10% per day so as to prevent accumulation of organic matter in the form of excess natural and artificial feed. Water change was effected by first draining 10% of the water and then replacing this with the same amount by pumping. This was done early in the morning so as to raise the dissolved oxygen level, which usually is still low in the morning.

2.6. Feed

The use of teri or fresh anchovies as supplemental feed was compared with the use of pellet either singly or in combination. When used singly both pellets and anchovies were given at the rate of 200% biomass per day during the first week. This rate was reduced by 50% every week. For the combination feeding, a total of 200% biomass was also used except that half of the ration consisted of pellets and the other half anchovies. The weekly 50% reduction was then done pro rata. The feeds were given 3 times a day at 0600, 1700 and at 2200 hours.

2.7 Rearing Period

The fry were reared for 4 weeks. The length and weight were monitored once a week.

2.8. Harvest

The fry were harvested by using a preyang, a trap made of bamboo screen. This was deemed to be the safest device to use to ensure minimum mortality during harvest because it does not injure the shrimps even if left in the water for some time. Besides it can be set from the dike so that the pond bottom is not disturbed by the harvesters. A 30 minute duration was sufficient to collect more or less 3000 shrimp juveniles. When it was estimated that about 60% of the stock has been harvested, a collecting net was installed at the catching pond and the water drained.

3. RESULTS AND DISCUSSION

As shown in Table 1, the shrimps fed with anchovies grew from a length and weight of 0.8 cm and 1.4 mg to 4.1 cm and 432.5 mg in Pond A and 4.1 cm and 432.9 mg in Pond B. The shrimps fed with pellets only and pellets plus fresh anchovies started at a length and weight of 0.7 cm and 0.8 mg but ended at 3.9 cm and 406.5 mg for the former and 4.2 cm and 395 mg for the latter.

From the sizes attained there do not seem to be very much differences in the different diets, considering that those fed with pellets either singly or in combination also had smaller initial sizes. However in terms of survival rate those fed only fresh anchovies had consistently higher survival rates at 77.57% and 85.7% for Pond A and Pond B respectively. While those fed pellets only did very poorly at 23%. Those fed pellets and achovies had a higher survival rate of 59.6% but is still lower than for those fed fresh anchovies only.

4. CONCLUSION

Due to the limited number of ponds, the different types of feed cannot be tested at the same time using the same batch of fry. The same reason also prevented replication that would have allowed statistical analysis.

It is possible that the lower survival rate in those fed with pellets alone or in combination with fresh anchovies is due to the fact that the fry used were very much smaller at 0.8 mg, than those fed fresh anchovies only which averages 1.4 mg. However the group fed pellet plus fresh anchovies had a much better survival rate (59.6%) than the group fed only with pellets (23.5%), both of which used the same size fry. This would seem to indicate that fresh anchovies has a good potential as starter feed for P. monodon fry during the nursery stage.

The results of this limited experiment should only be considered indicative. More ponds should be provided to allow for simultaneous testing of different feed combination as well as replication so that proper statistical analysis can be conducted.

5. REFERENCES

Djunaidah. I. S. and Busman S. 1986 Growth and survival rate of Penaeus mondon postlarvae given four different formulated feeds: Bull Brackishwater Aqua. Dev. Cent. VIII (1), pp. 20–24.

Sutjipto, Y. S. 1980 Effect of feed quantity, shelter, density and salinity in the mortality of P. monodon fry in a holding pond (in Indonesian). Fakultas Peternakan dan Perikanan, Universitas Diponegoro, Semarang.

Noor Hamid 1986 Production of shrimp juvenile in earthen nursery pond. Bull. Brackishwater Aqua. Dev. Cent. VIII (1), pp.31–42.

Pascual, F.P. and W.H. Destajo, 1978 Growth and survival of Penaeus monodon postlarvae fed shrimp head meal and fish meal as primary animal source of protein quart. SEAFDEC AQD Research Report, 1st quarter (Jan-March), pp. 26–30.

Table 1. Growth and survival of P. monodon postlarvae cultured for 4 weeks in earthen nursery ponds.

SHRIMP INDUSTRY DEVELOPMENT IN EAST JAVA

East Java Provincial Fisheries Office

ABSTRACT

The development of the shrimp culture industry in East Java started in 1975 with polyculture of shrimps and milkfish. Intensive monoculture started only in 1986 in Banyuwangi but now has grown to include 396 companies/entrepreneurs spread over 17 regencies and covering a total of 5,146.7 ha. Along with shrimp tambak development, the hatcheries also developed rapidly so that at present there are already 57 units spread out in 5 regencies within the province, with individual capacities ranging from 20–30 million per year. Other support industries such as feedmills and freezing plants have also developed accordingly.

The development of the industry has not been without problems. In the tambak the usual problems encountered include conflicts in land use, lack of master plan, water supply and financing. On the part of the hatcheries the problems include fluctuation in fry demand and diseases. The disposal of wash water and shrimp heads and shells from shrimp processing plans also poses a problem for the communities around the plants. Nutritionally deficient feeds have been pointed out as contributing to the occurrence of blue shrimps. Ways to overcome the various problems are suggested.

1. INTRODUCTION

The shrimp industry sector in Indonesia, especially in East Java during this period is experiencing very rapid development, alongside the government policy of encouraging the development of non-oil export commodities. Indonesia has a large advantage and opportunity for non-oil exports, especially shrimps, both in terms of market as well as in production, taking into account the climate, manpower, along with other supporting elements. The government's effort and the private sector's role in stimulating shrimp culture activity are already showing visible results. This is reflected in the increased shrimp exports in terms of volume as well as income received.

Inspite of the success already attained, several problems are being faced. Among others, these problems include the drop in shrimp prices in foreign markets, effect on the environment of salt-water intrusion due to shrimp culture, as well as the continued detention and rejection of Indonesian shrimp products by US authorities because their quality are considered to be less than satisfactory and other similar reasons. In this connection there is a need for greater awareness on all parties concerned including farmers, entrepreneurs, as well as the government. Using the stock knowledge that has been obtained so far, everyone involved can move forward together in locked-steps towards the creation of a healthy and advantageous condition so that in turn this will spur the increase in the income of the community in general and the tambak farmers in particular.

This paper shall attempt to propose general guidelines on the development of the shrimp industry in East Java as well as propose solutions to the various problems being faced.

2. SHRIMP INDUSTRY DEVELOPMENT IN EAST JAVA

A discussion on the shrimp industry actually requires a discussion of a fairly broad range of activities. These activities range from the production of shrimp fry, the rearing of fry to a stage ready to be stocked, grow-out until harvest, storage and packing in cold storage plants, along with support industries in the form of feedmills, pesticides, water conditioners, and various pond equipment. All of these components shall be discussed according to the order of their involvement.

2.1 Production Potential and Aquaculture Development

The tambak area in East Java covers 54,000 ha, of which about 65% is within the areas of Gresik, Surabaya, Sidoarjo and Pasuruan.

Pioneering efforts in shrimp culture development in East Java began with the application of polyculture technology involving shrimps and milkfish in 1975 with the support of credit facilities from the World Bank and IBRD, and was continued in 1979 by the granting of credit facilities from the Rural Credit Project of the World Bank. Afterwards, based upon KEPPRES 39/1980, credit was made available for tambak aquaculture (old and new methods) which was later coursed through the INTAM Kredit programme. With the support of the various credit facilities mentioned above, some tambak farmers have started to practice shrimp monoculture. In 1988, about 4,668 ha of tambak has been registered as being used for shrimp culture in monoculture as well as in polyculture with milkfish through the INTAM Swadana programme, which means 74% of the projected 6,323 ha.

However it cannot be denied that the development of intensive shrimp monoculture in East Java started only in 1986, and was initiated by an entrepreneur (who later formed PT Mutiara Blambangan Permai), in the Village of Sumberberas, Subdistrict of Muncar, Banyuwangi Regency. This initial venture into intensive shrimp monoculture was done in a 1.25 ha pond which was stocked with 110,000 shrimp fry, and harvested 2.5 tons after a 4.5 month rearing period. This activity emerged after the success of shrimp culture operation of PT Monodon Kencana in Sidoarjo Regency was seen. The rise in shrimp prices on one hand along with the emergence of entrepreneurs who had accumulated capital (generally rice-mill operators) in Banyuwangi, on the other hand, helped very much in accelerating the development of the shrimp industry in this region.

With the support of a good communication network, the development in Banyuwangi spread rapidly to its neighboring areas such as Situbondo, Jember, Probolinggo and then to Tuban and other areas within East Java. With such a rapid development, during a very short time, there are now 396 enterprises, both single proprietorship and companies, that have registered to operate intensive shrimp farms. These are distributed among 17 regencies and covers a total area of 5,146.7 ha as can be seen in Table 1.

With technological development, tambak development was no longer limited to tidal areas, but with the use of large capacity pumps even areas above the tide were being developed for shrimp culture. Coconut plantations, rice fields, or even dry, un-irrigated fields, as long as they are near the sea coast, were being converted into shrimp farms. Moreover even sandy areas which used to be unusable for tambak purposes were now being utilized. With the use of heavy equipment, the sandy top soil are scraped, disposed, and changed with clayey soil. With such development, there is a need to exercise caution especially if a well is used to draw subterranean ground water for use as water supply. If these are not regulated and monitored, it is feared that it would have a negative impact on the environment in terms of saltwater intrusion thus contaminating the water supply for domestic as well as agricultural use.

In order to balance the interest of the community against that of shrimp culture operations, an inventory of potential areas for shrimp culture was undertaken in the southern coast of East Java. A total of 6,251 ha was development, as follows:

These are the Shrimp Hatchery Centre in Probolinggo, the PPUW in Pasir Putih, Situbondo and two shrimp hatcheries constructed under the ADB-assisted BADP Project, one of which is in Situbondo and the second in Tuban.

The number of private shrimp hatcheries on the other hand has jumped from only 5 units in 2 regencies at the beginning of PELITA IV, to a total of 57 units in 5 regencies by the end of PELITA IV, can be seen in Table 2. These hatcheries have an annual capacities ranging from 20 to 30 million fry. Regarding backyard-scale hatcheries which is being promoted by BBAP Jepara, so far only 4 pioneering units have emerged, all in Situbondo.

It does not appear to be possible to obtain accurate figures for shrimp fry production from private hatcheries because most never report their production results. As a result, it is not possible to lay down policies on shrimp hatchery development, such as for instance to temporarily limit the number of hatcheries so that the existing hatcheries shall be able to operate at full capacities, as well as for other purposes.

2.3 Cold Storage Plants

The development trend of cold storage plants is similar to that of the shrimp hatcheries. From only 12 units at the start of PELITA IV, these increased to 29 units by the end of PELITA IV. These are found in 4 areas as can be seen in Table 3. The increase in the number of processing plants means a corresponding increase in the total capacity from 1,730 tons/day at the start of PELITA IV to 5,555 tons/day by the end of PELITA IV.

2.4 Support Industries

The development of shrimp culture industry was accompanied by the development of support industries such as the feed industry. At present there are 6 feedmills registered in East Java, these are:

• PT Comfeed Indonesia, Sidoarjo;
• PT Bamaindo Foodstuf, Sidorjo;
• PT Charoen Pokphan, Sidorjo;
• PT Tunggal Eka Sakti, Surabaya;
• PT Feng Li, Surabaya;
• PT Windu Fairly, Surabaya.

Even with these feedmills, various brands of shrimp feeds are still being imported from Taiwan. The tendency of the shrimp growers to prefer imported over local brands of feed has already started to decline. This is probably partly due to the drop in shrimp prices which prompted the shrimp growers to find all means of reducing production costs. Some are using local feed mixed with imported feed. This is actually a good opportunity for the local feedmills to improve the quality of their product as well as their after sales service. It is hoped that the shrimp feed requirement can be filled by locally produced feeds.

In terms of equipment and other inputs, there are already many distributors especializing in aquaculture supplies such as pumps, paddlewheels, water quality test kits, and various water conditioning substances such as zeolite and bentonite.

3. SHRIMP INDUSTRY PROBLEMS

3.1 Tambak

3.1.1 Land use system

The mapping of land use is a basic requirement for the development of an area. Control over areas which still do not have a land use map is often less than satisfactory. As a result conflicts in their usage between persons or companies are often encountered in such areas.

3.1.2 Master plan

In designing their tambak system, the parties concerned often do it individually without considering the rest of the area surrounding their own farm. This occurs because there is still no master plan which would regulate the number and the lay out of tambaks according to the capacity of the environment in terms of fresh and sea water, disposal of waste water and other ecological factors. The result is that existing tambak operations already exceed a particular area's capacity so that they can no longer be managed or operated correctly, thus ending in not small losses.

3.1.3 Water supply

The management of salinity during the grow-out period is very important in ensuring the health and growth of the shrimps. The traditional tambaks generally have great difficulty in managing their salinity because their water canals are not satisfactory and are almost not maintained at all.

In order to overcome this problem, the rehabilitation and repair of canals is needed. Aside from this, the drilling of wells to draw ground water, whether fresh or brackish, especially during the dry season when the salinity rises or during the wet season when the salinity is too low, can help solve this problem. However there is also a need to properly manage the drilling of wells for fresh water in these areas due to the possibility of saltwater intrusion inland.

3.1.4 Working capital

On the part of the small farmers, working capital is a limiting factor even if they operate their tambaks using only extensive or traditional methods. Credit such as that available under INTAM has certain requirements which appears to be still beyond the reach of farmers so that the realization rate of INTAM Kredit is relatively low resulting in the stagnation of its execution. A Special INTAM programme (OPSUS) was implemented according to the Letter of Instruction No. 1 of the Regent of Gresik, dated 25 February 1988, in the Village of Ujung Pangkah Wetan, Ujung Pangkah Subdistrict, covering 152 ha. Up to this time, there is still a need to continuously develop and manage the area so that the expected harvest can be obtained. The fry required by the Windu Kencana group under this programme has been provided by PT Permata Hijau and BBAP Jepara while feed are provided by PT President Feed and Golden Horse (PT Laut Tambak Subur).

Pioneering efforts involving joint ventures between large companies and small farmers through the bapak angkat system have also been started. Two such ventures are:

• The farmers group in Kaliargo, Bangil Subdistrict, Pasuruan Regency in cooperation with PT Indo Udang Mas Lestari which covers 50 ha; and
• The “Minadon” farmers group in Wonorejo, Rungkut Subdistrict, Surabaya, together with PT Modern Surya Jaya, a cold storage company, which involves 175 ha appears to have been discontinued after only 2 to 3 cycles.

3.2 Shrimp Hatcheries

3.2.1 Fluctuation in fry demand

Even if there are already many intensive shrimp farms in East Java which are not dependent on the climatic season, there still does not seem to be synchronization between fry supply and demand. This can be seen in the fluctuation of shrimp fry prices which could drop as low as Rp. 10 per piece but rise to Rp. 15 per piece during peak season (for PL-20 stage).

With the emergence of so many shrimp hatcheries, there is now a lot of competition in terms of quality and service between the various operators. It is no longer rare for hatcheries to agree to a “payment at harvest” basis. This is also being practiced even for other types of inputs.

3.2.2 Diseases

In East Java, the hatcheries are concentrated in Situbondo regency followed by Banyuwangi. This is very convenient to the buyers because if one hatchery does not have any stock one does not have to go far to find another hatchery with sufficient stock. However there is also one disadvantage to such concentration because if one hatchery is infected by diseases, there is also a very high probability of the other hatcheries getting contaminated due to the common water source where the waste waters are also disposed. There is still no control measures regulating the disposal of waste water by hatcheries.

3.3 Processing Plants

Many processing plants are located near population centres. If a particular palnt does not properly dispose of their wastes in the form of heads, shells as well as wash water, these are likely to annoy the people living nearby and can become a health hazard. Such case is actually disadvantageous also to the existence of the plant since it would be deemed to have violated laws regarding the environment.

3.4 Feed

Lately, in intensive shrimp farms, the problem of blue shrimps have emerged. Such shrimps have low prices because according to the buyers, the Japanese consumers do not like such color. This has been attributed to problems in pigment formation due to specific factors, alone or in combination with others, including the nutritional composition of the feed which may lack the substance responsible for the formation of the proper pigments.

4. RECOMMENDATIONS

4.1 Tambak

1. In order to prevent conflicts over the use of the areas along the coast, the Regent of a given area should issue a decree defining the tambak area before the land use map is published. This was done in the regencies of Banyuwangi and Situbondo.
2. Since the concept of a master plan for tambak areas has not yet been applied, and since the government has limited funds for implementing such concept, perhaps this role should be delegated to the private sector by encouraging interested and financially capable parties to pioneer in the development of “tambak estates”.
3. Since the amount involved for rehabilitating canals is enormous, there is still a need to tap foreign sources of fund for projects similar to that funded by the Asian Development Bank which has already rehabilitated about 90 km of canals in Gresik, Sidoarjo and Pasuruan.
4. Regarding the difficulty of obtaining working capital on the part of the small farmers, joint ventures between the farmers and large companies using the bapak angkat system should be encouraged. Furthermore the OPSUS INTAM programme should be expanded to other areas.

4.2 Shrimp Hatcheries

1. In order to prevent unhealthy competition among hatcheries, there is a need to think about forming a “shrimp fry bank” which will coordinate a cooperative marketing system to operate during both peak demand and slow demand season. With such a system it is hoped that the shrimp price will never go down below the production cost.
2. Post-sale service for shrimp fry including among others fry acclimatization especially for small farmers who do not have any means of monitoring salinity will be one way of helping reduce mortality during stocking.
3. The time has already come to do something about the disposal of waste waters from the hatcheries and tambaks so that there will be an assurance that the water disposal shall be according to fixed standards. Aside from this there is also a need to regulate the use of chemicals and antibiotics for controlling diseases.

4.3 Shrimp Freezing Plants

There is a need to strictly enforce the hygienic requirements in the operation of shrimp freezing plants and make them follow environmentally sound practices. In addition there is a need to start thinking on how to utilize the chitin from the exoskeleton and heads of shrimps. Chitin and chitosan are used widely in modern industry, among others, for water purification, in agriculture, food industry, health and cosmetic industries.

4.4 Feed

With the occurrence of blue shrimps, the feedmills should be urged to continuously improve the quality and nutritional content of their products. In addition the use of natural feed as an alternate feed should be encouraged in order to prevent the occurrence of blue shrimps.

Table 1. Number of intensive tambak operators and area developed per district in East Java.

Table 2. Number of private shrimp hatcheries in East Java.

Table 3. Total of cold storage plants in East Java.

SHRIMP FEED DEVELOPMENT

I Putu Kompiang
Centre for Training and Education, Maros, South Sulawesi

ABSTRACT

In developing shrimp feed, the biological characteristics of the shrimps should be considered and the feed formulated accordingly. One such characteristic of the shrimp that is very important is its carnivorous feeding habit, which therefore requires the feed to approach the composition of animal organisms, or in other words, to have a high protein level.

Shrimp feed for pond use consists of three types, namely, starter, grower and finisher. The levels of the primary nutrients of the three types of feed vary as follows: protein: 40–45%, 38–40%, and 35–38% for starter, grower and finisher respectively; fats: 10–12%, 8–10% and 6–8%; and carbohydrates: 20–25%, 25–30% and 30–35%. Aside from the primary nutrients, other essential ingredients are: binder, attractant, vitamin-mineral mix, cholesterol and phospho-lipids. The method of formulating shrimp feed is discussed.

1. INTRODUCTION

Lately, shrimps have become an important commodity in terms of earning foreign exchange from nonoil exports. This was made possible through the efforts of the government as well as the private sector. The government through the Directorate General of Fisheries together with the Agricultural Research and Development Institutes have continuously provided technical guidance in culture, techniques, postharvest handling, marketing and other related aspects. All of the government agencies concerned have had good response from both the largescale and small-scale entrepreneurs.

In shrimp culture, feed is the most expensive item in the production cost. In intensive culture, feed constitutes about 60–70% of the total production cost. Because of this, feed both in terms of quantity and quality, should be given very serious attention. In this connection, the freshness of feed is one very important consideration. Freshness can be obtained only if the feeds bought has been newly formulated or if these are made by the shrimp growers themselves.

As a contribution to shrimp culture development, this paper has been prepared with the hope that it would be useful or can be of assistance to shrimp culturists. The contents of this paper is based on our experience in shrimp feed development for the past 2 years.

2. BIOLOGICAL CHARACTERISTICS OF THE UDANG WINDU

The udang windu (P. monodon), is a saltwater shrimp that in nature grows to a size of up to 250–300 g, however in the tambak, the weight attained at harvest is generally up to 30–40 only. It is considered a carnivore, although during its culture it should still be given feed of plant origin. In other words under culture conditions it becomes an omnivore. Considering its natural feed habit, it is therefore best to have the composition of its feed approach that of animals, or in other words, for its feed to have a high protien level.

In terms of activity period, P. monodon is a nocturnal animal, that is, they are more active at night than in the day time, even in looking for food. Because of this, it is better to feed them at night.

In terms of feeding habit, it can be considered a “slow eater”. This is because it has a very simple digestive tract which does not include a stomach. Therefore it has to eat continuously. Because of this, feed should be made available at all times so as to prevent cannibalism.

3. REQUIREMENTS FOR P. MONODON FEED

The requirement in terms of nutritional content of P. monodon feed depends on the stage of development of the shrimp. Thus it is common to have at least three types of feeds: starter (for PL-25 up to 1 g size); grower (for juvenile shrimps) and finisher (for bigger shrimps up to harvest). The nutritional content of each type of feed can be seen in Table 1.

4. FEED COMPONENTS

4.1 Primary Components

4.1.1 Protein

A high protein level is required for P. monodon because this shrimp is basically a wild animal, for which the best energy source is protein. Aside from a high level of protein, the protein quality should also be high. Because of this, the formulation of P. monodon feed requires a high level of animal protein. From 60 to 70% of the protein should come from animal origin, such as fish meal, in order to obtain good development. Some of the protein sources that can be used can be seen in Table 2.

4.1.2 Fats

Fats is an essential requirement for P. monodon, especially fats which consist of unsaturated fatty acids such as fish oil, fish liver oil and similar substances. In formulating shrimp feed, at least 70% of the fats should come from fish oils. The ratio of fish oil to vegetable oil should be about 5:1. Sources of oil that can be used include oils from various fish species (sardines, herring, salmon, etc); and vegetable oils such as soybean oil, corn oil, palm oil and others.

4.1.3 Carbohydrate

Carbohydrate is the third essential macronutrient. Generally shrimps have difficulty in digesting carbohydrates. Because of this, care should be taken that the crude fiber content of the formulated diet is not too high. Some of the good carbohydrate sources are: wheat flour, tapioca and rice flour. Rice bran as well as wheat pollard should be used only in very limited quantities.

4.2 Additives and Other Components

4.2.1 Binders

Binders are needed to maintain the stability of the feed in water. There are various types of binders available in the market. Some are simple substances while others are compounded from a combination of various substances. Most are effective even if only simple equipment are used such as discussed below. In order to obtain a 4 to 8 hours stability, 4 to 6% binder is required depending upon the type of binder used. Some of the commercial binders usually used for feed formulation are wheat gluten, CMC, carageenan, agar and guargum.

4.2.2 Attractant

It is necessary for the feed to be taken by the shrimps as soon as possible in order to minimize disintegration and the possibility of its getting imbedded in the muddy bottom. Attractants at the rate of 2 to 4 kg/ton are therfore required. Substances which are effective as attractants contain compounds of short peptides and amino acids such as fish solubles or fish silage.

4.2.3 Vitamin mineral premix

Shrimps require vitamins and minerals for growing. In addition to the vitamins that are usually required in animal feed, shrimps require Vitamin C, choline and inositol. Premix is a combination of vitamins and minerals which fills the requirement of the shrimps. It is applied at the rate of 6 to 7 kg/tons feed depending upon its concentration.

4.2.4 Cholesterol and phospholipids

Cholesterol and phospholipids are two of the essential nutrients required by shrimps. The usual sources of these nutrients are shrimp head meal and squid meal. Cholesterol can partly be replaced by phytosterol, or sterols of plant origin. Mean while phospholipids can be found abundantly in soybean oil. The level required ranges from 0.5 to 1.0%.

5. EQUIPMENT NEEDED

The equipment needed for formulating shrimp feeds are as follows:

1. Grinders or mills which are capable of pulverizing materials down to a particle size of 400 micron or smaller. Rotary mills and similar machines can be used by changing the mesh size of the screens. A capacity of 50 to 100 kg/hr will be sufficient to supply a 3 to 5 ha tambak.
2. Mixers, with capacity depending upon the required production level. A mixer capable of mixing 25 kg at a time should be sufficient to produce enough feed for a 3 to 5 ha tambak.
3. Balances. Two types are required. A large capacity balance capable of weighing from 5 to 10 kg and a more sensitive scale with a maximum capacity of 1 to 5 kg.
4. Steamer for heating or cooking the feed mixture before pelletizing. An ordinary steaming pot can be used for this purpose.
5. Pelletizer. A meat grinder can be used after some modification so that the holes where the pellets emerge will have a diameter of 2.0 to 2.5 mm.
6. Drying racks where the pellets can be spread for drying.

6. METHOD OF MAKING FEED PELLETS

Once all the required equipment and ingredients are ready, the feed pellets can be made according to the following steps:

1. All of the ingredients should already be in the form of fine particles (400 micron or less). Uniformity of particle size is important to attain greater stability.
2. All of the ingredients should be throughly mixed. A 10 to 15 minute mixing time in the mixer should be sufficient. Steam or hot water is added while mixing up to a moisture content of 25 to 30% so that the feed mixture can be kneaded into the firm lump.
3. The feed mixture is fed into the pelletizer for extrusion. In about one half hour of operation the casing of the pelletizer will become hot. Once this condition is already attained, the actual pelletizing can proceed continuously. The feed mixtures extruded before the pelletizer casing became hot should be re turned to the pelletizer and re-extruded. Heating is necessary to assist in the gelatinization of the binder.
4. The pellets that have been produced are then spread out and allowed to cool down and aired in a sheltered area not directly exposed to sunlight.
5. Once the pellets have cooled down these are then allowed to dry. A dryer would be convenient for this purpose. However the feed should not be exposed to direct heat. This is important to keep the pellet stable.
6. After drying this should be kept in air-tight bags. The pellets should not be stored too long. The sooner it is used, the better. The pellets can be stored for 3 to 6 weeks if it is properly dried. If anti-fungal as well as anti-oxidant are used, the pellets can be kept longer.
7. The feed should be stored in a dry place that is not directly exposed to sunlight.

Table 1. Required nutritional composition of P. monodon feed.

*) Includes cholesterol and phospholipids.
**) Includes only crude fiber of plant origins, do not include those from shrimp head meal.

Table 2. Suggested limits in the use of some protein sources.

Table 3. A typical shrimp feed formula.

Notes: MFB 89 is a binder that is formulated from various materials. The amount to be used should first be determined in test runs to see at what level it is most efficient. MAT 88 is a mixture of various peptides and amino acids extracted from fish liver and entrails. MITRAMIX is a mixture of vitamins required for shrimp growth.