PART II
CONTRIBUTED PAPERS

LIST OF CONTRIBUTED PAPERS (CP)

FAO/UNDP-SCSP WORKING PARTY ON SMALL-SCALE SHRIMP/PRAWN HATCHERY

Semarang, Central Java, Indonesia
15–22 November 1981

SPONSOR: FAO/UNDP South China Sea Fisheries Development and Coordinating Programme

HOST INSTITUTION: Directorate General of Fisheries
Ministry of Agriculture of the Republic of Indonesia

SMALL-SCALE SHRIMP/PRAWN HATCHERIES: AN OVERVIEW¹

by

H. R. Rabanal²

1. BACKGROUND

The total existing production area which can be used potentially for raising shrimps and prawns in the ASEAN countries covers about 500 000 ha. This consists about 370 000 ha of saline areas (brackish and marine) and 130 000 ha of freshwaters. These are geographically distributed as follows:

* No data

NOTE: Based on 1978 figures (SEAFDEC, 1980)

From available information, it is very difficult to get an accurate estimate of the total production from these areas. This is because these ponds are not solely used for shrimp and prawn culture only, but most of these are used mainly for various species of finfish. Also, that the seed supply of cultivable shrimps and prawns is not yet stable resulting in high fluctuations of production for this group from year to year.

It is of interest to note, however, that if these existing production areas were fully utilized for shrimp/prawn production, some 300 to 1 000 kg per hectare can be produced from them each year or about 150 000 to 500 000 tons per year.

To fully utilize the existing developed areas in ASEAN for shrimp/prawn production would require a stock of 25 000 million surviving juveniles (based at stocking rate at 5 per m²). If we grant that only 30 percent survive to juvenile stage from postlarval stages raised in hatcheries, the amount of postlarval stock required by existing production space will amount to about 83 300 million. It is clear that only a small fraction of this total requirement is being produced in the ASEAN countries at present. There is further the expansion of pond areas above existing acreage also to reckon with. Of course, it should also be noted that not all the existing ponds may be shiftable for shrimp/prawn culture; we can figure on 30 to 50 percent as perhaps suitable or 160 000 to 250 000 ha. This will require 26 600 to 41 600 million seed stock annually.

¹ Based on the mutual but unwritten agreement during the FAO World Scientific Conference on the Biologu and Culture of Shrimps and Prawns, Mexico City, Mexico. 12–21 June 1967.

The term “shrimp” in this Working Party will be used for the cultivable saltwater penaeid species while “prawn” those of the palaemonid freshwater forms.

² Consultant (Aquaculture), FAO UNDP South China Sea Fisheries Development and Coordinating Programme. Manila, Philippines

In assessing the status of shrimp/prawn hatcheries in the region, the Working Party found that there are a total of about 130 hatcheries various kinds and sizes and in various stages of development. Of these, 71 are penaeid shrimp hatcheries mainly for Penaeus monodon, and 59 are for prawn (Macrobrachium rosenbergii). Most of the hatcheries are privately-owned — 52 for shrimp, 45 for prawns; government-owned are 19 for shrimps and 14 for prawns. Of the total number only 117 are operational (64 shrimp, 53 prawn) while 13 are under construction (7 shrimp, 6 prawn). These are shown in the Table 1.

Data of production from existing hatcheries in the region, based from 1978 and 1980 estimates showed a total of 58.9 million shrimp/prawn fry produced of which 30.9 million were shrimp and 28 million were prawn. This is a far cry from the total estimated maximum requirement of 25 000 to 40 000 million.

It is therefore clear that stable production of juveniles to stock production ponds will result in stabilizing this industry and ensuring its continued existence and gradual development.

2. SCALE

The usage of the terminology “small-scale” has often been subject to question. This is mainly because of the difficulty of identifying where this begins and where it ends, i.e., its limits or boundaries.

There may be a number of approaches by which we may define “small-scale” from “big-scale” or even “small-scale” with “medium-scale” and “big-scale”. This can be under the following criteria:

1. in amount of capital and operational investment
2. in area or extent covered by project
3. in amount of produced stock and the resulting income
4. in ownership and operational procedure

In all the above criteria, the limits are vague and can slide from one boundary to the other. What is important to bear in mind in this case, however, is the socially oriented objective of the various scales and in particular for the small-scale project. It is our aim in a small-scale project to provide an opportunity for the fishermen or farmers with limited means, and working individually, to possibly make a living, generate additional employment for his family and help in the food production and economy of his country.

Suppose we arbitrarily designate, just to make a start, small projects with the following characteristics:

1. capital investment not exceeding equivalent of US$50 000 and yearly operations not exceeding US$10 000;
2. area from few square meters up to but not exceeding 0.5 ha (5 000 m²);
3. production up to 10 million postlarvae per year, with corresponding income thereof;
4. ownership by fisherman or fish farmer using his family or immediate relatives for labour.

The above specifications are very arbitrary and open to suggestions. It may even be inadvisable to do this, but alternatively describe its quality characteristics of what a small-scale venture is.

3. CONSTRAINTS

As this will be a new venture based on technology of recent development, lack of training to supply the required know-how will be an initial handicap. There is no anticipation of difficulty in marketing the product, but still this has to be studied and assured before projects in this field can be encouraged. What is even more important in this case is to ensure price stability for the crop of the would-be producer.

Moderate and easily available financing will be needed to acquire facilities not readily available within the farmers environment, especially those that are brought from outside sources.

Organization of the industry through government initiative will do a lot to keep it within controllable limits and thus prevent future collapse. Cooperatives have not worked well in this region but some form of exchange and mutual understanding among the producers initiated through the government can be helpful.

4. TASK OF WORKING PARTY

The Working Party should assess the progress that has been started in seed production through hatcheries of cultivable shrimp and prawn species with emphasis on small-scale ventures. The centres of development in the different countries and the extent which such centres has attained should be determined.

There is so much diversity in design and construction. Many of the design innovations may be without purpose but were developed merely from imported technology and information. Designs adapted to the countries in the region should be determined. A model, if possible, should be identified by this Working Party. Alternative models to suit peculiar situations in the region should also be considered.

Likewise, management or operational procedures appear to be very diversified. Again, the influence of imported technologies have initially prevailed. This Working Party should try to prepare the cookbook of operations suited to the countries in the region. The various components of management should be segregated and the procedures by which these should be handled determined (feeding, disease, control, water quality monitoring, etc.)

This Working Party should also look into the economics of small-scale shrimp/prawn hatchery ventures. Proper measures to ensure proper disposal of produce, marketing and handling of crop from this source should be determined.

5. FUTURE PROGRAMMES

The technical base of this undertaking should be firmly established through research. Future research programmes to strengthen this technical base should be formulated.

Development programmes based on technology already developed and to be developed should be discussed and this ideas taken home by the participants of this group for recommendations to their respective agencies.

Training/extension needs will be identified in the course of this consultation. The kind of training, where this training can be available and additional training required should be determined.

Table 1.

Existing shrimp and prawn hatcheries and those under construction in the region

(S)* = shrimp;
(P)* = prawn;
(?) = no data

Table 2

Fry production of the existing hatcheries in the region

* Annual average 12.5 m

WP/81/SPH/CP-2

PRESENT STATUS OF SMALL-SCALE PENAEID HATCHERY IN INDONESIA

by

Sukotjo Adisukresno¹

1. INTRODUCTION

Indonesia has total area of brackishwater farms of approximately 180 000 ha. These area are mostly used for the culture of milkfish, and shrimp during the rainy season. During the dry season (May—October), in some regions, the ponds are altered into salt farms. The ponds are stocked with milkfish fry and shrimp which are collected from several fry grounds scattered in various areas in Indonesia. The fry are available seasonally, first season between September and November, second between May and July.

One of the main problems in shrimp culture is the limitation of shrimp fry to stock. Although in certain areas the fry is available from coastal waters, their numbers fluctuate, unpredictable and are available only seasonally. Shrimp culture still rely mostly on wild stock for their requirement.

The government of Indonesia initiated a National Shrimp Development Programme in 1979. This Programme intends to intensity 100 000 ha of brackish-water ponds, extensification of 31 000 ha ponds and stimulate the private sector to invest their capital on shrimp hatchery. The government also provided loans for hatchery construction and operations. To fill the skilled personnel requirement the government has conducted several training programmes on hatchery operations.

The government gives technical assistance on site selection and survey of the suitable place for hatchery for the private sector. Several private small-scale hatcheries have been constructed and some of them are now in operation.

Although it is technically feasible to produce shrimp fry from hatchery, the technology should be improved to the level where the operation is efficient and cost of production sufficiently low.

2. SITE SELECTION AND SURVEY OF HATCHERY

Considering time, effort and amount of investment needed in venturing into any hatchery enterprise, a proper evaluation and study is necessary in selecting the site where such hatchery is proposed.

In site selection the following factors should be considered:

• seawater quality
• tide fluctuation
• distance to the brackishwater farms
• manpower availability
• freshwater supply
• regional development plan

2.1 Seawater quality

Salinity of seawater should be around 28–32 per mille year around. The larvae grow better on the salinity of around 28–30 ppt. Location near estuarine areas is avoided.

Clean seawater during the whole year around, is preferable with transparency around 2–3 m. Turbid water might be altered into clean water by sand filter but the dissolved organic matter might be still in the filtered water. The dissolved organic matter is a good medium for the growth of bacteria and fungi, so turbid water should be avoided.

Seawater should be free from pollution. Location near industrial area, trade or fisheries harbour or where the sea current face toward the location from the industrial area or from the streams that bring down water from the ricefields should be avoided.

¹ Director, Brackishwater Aquaculture Development Centre, Jepara, Central Java, Indonesia

2.2 Tide fluctuation

Distance between low-low tide line and high-high tide line along the shore where the hatchery is located should be less than 100 m. This has to do with the piping system for pumping seawater. If the distance is far, the piping system installation will be very expensive and it will need more powerful pumps which would be more expensive.

2.3 Distance to the brackishwater farms

This has reference to fry transportation; according to experience, there is no mortality if transportation is done within less than 10 hours by road. Also, the continuous and easy supply of broodstock can be available from the farms, if the hatchery operates on eyestock ablation of spawners.

2.4 Manpower availability

The location should not be far from the village to make sure that manpower is available. Another factor to remember under this situation is to avoid personnel in the hatchery from feeling being located in an isolated area, so that they can concentrate on their job for long periods.

2.5 Freshwater supply

Good quality of freshwater for daily life, laboratory work and miscellaneous work should be available at the site.

To predict whether freshwater is available in a given place, some simple observation might be used:

• is there any well with good quality of freshwater around the place?
• is the location near a mountaineous area which is still dense with forest?
• is the location with big trees which are still green during dry season?

To make sure whether freshwater is available a hydrological survey should be conducted.

2.6 Regional development plan

The site location of a new hatchery should be synchronized or harmonized with the regional plan of development. Information on the regional development plan is available from the government in the region. The area which is planned for industrial, harbour or recreational purposes should be avoided. Pollution might arise in the future and also many problems need to be solved in such areas.

2.7 Miscellaneous considerations

The site location should be easily reached by vehicles, for the benefit of fast transportation of brood-stock, fry and supplies.

A site which is safe from typhoons, strong waves, or floods is preferable.

3. DESIGN AND CONSTRUCTION

3.1 The breeding tanks

The breeding tanks are optional in size, shape and material. In most cases, the tanks made of concrete, rectangular of size about 35 to 80 m³ or measuring 5 m × 5 m × 1.5 m to 8 m × 5 m × 2 m, respectively.

In other cases, the tanks were made of bricks surfaced by concrete masonry or bricks reinforced with concrete columns at appropriate intervals. In this case, the construction cost is much cheaper but found durable enough. Tank construction of bricks reinforced with concrete columns, has the strength of 0.21 kg/cm², while the water pressure is 0.17 kg/cm² when the 2 m high tank is filled with seawater (Figure 1).

Figure 1. Tank of bricks with reinforced concrete columns

The tanks are provided with stand pipe drains made of PVC pipe of 4" in diameter; all piping system should be made of PVC. To avoid direct sunlight, the tanks are located under plastic roofing, asbestos roofing or even with roofing of palm leaves. Plastic fiber glass roofing make the light intensity high, the sunlight penetrate with high illumination, causing the maturation of the brood stock not efficient. Asbestos roofing results in dark condition with no direct sunlight entering the tanks, but the temperature underneath is warm during the day time. Roofing of palm leaves prevents direct sunlight, and the temperature is cool enough during day time and the water temperature relatively constant during night time.

3.2 Seawater reservoir

Seawater reservoir is constructed as a tower of about 4 m height. Underneath the reservoir is constructed as room for seawater pump, blower and storage to reduce the cost of construction. The tank measure 6 m × 2 m × 2 m respectively, made of brick reinforced with concrete columns (Figure 2). The tank consist of 2 parts, one for the reservoir and sedimentation tank, while the other for sand filter. Seawater is pumped into the tank and after passing the sand filter it is distributed to the maturation tank and hatchery tank by gravity through PVC piping.

Figure 2. Seawater reservoir

3.3 Larval rearing tanks

Larval rearing tanks are made of wooden box with plastic lining or concrete tanks or fibre glass tanks.

Wooden boxes with plastic lining measuring 4 m × 4 m × 0.6 m or 3 m × 3 m × 0.6 m are being used. These tanks can be constructed quickly and use only material which are available locally and the cost is cheap. The wooden box can last more than 4 years and the plastic lining will last within 1 year (Figure 3).

Concrete tanks are optional in size and shape. Some of the hatcheries use rectangular concrete tanks measuring 4 m × 4 m × 0.6 m, 6 m × 2 m × 0.8 m, or even smaller tanks of 2 m × 2 m × 0.6 m. These tanks are usually made completely of masonry plustered brick construction which are relatively cheap and durable. Newly constructed tanks usually cause serious mortality to the larvae. Other hatcheries use larval rearing tanks that are circular, measuring 1–1.5 m in diameter, 0.8 m in depth with conical bottom.

Fibre glass tanks, with conical bottom and double walled is planned by a private hatchery. These tanks are easy to construct but these are comparatively expensive. The disadvantage of the fibre glass tanks is the additional expense for support construction for the tanks. These tanks are durable and can be used for culture with high density of the larvae.

All of these tanks are located under roofing construction. Some of the hatcheries construct barn with roof of palm leaves. This construction make the temperature inside cool during day time and the temperature does not fluctuate much during night time. There is no direct sunlight to the tanks. This roofing might last around four years.

Corrugated plastic roofing is also used in some hatcheries. This construction might allow more light to the tanks and warm temperature might be produced inside the barn.

This material has the following disadvantages:

1. becomes opaque after certain period
2. becomes brittle after sometime of exposure in sun-light

3. it can not withstand strong beach winds.

The advantage of this construction is that it is relatively cheap and fast in construction.

3.4 Associated facilities

The aeration system mostly used is Vortex Hitachi* blower, 500 watts, outlet 2" and the capacity is 1.6 cubic meters per minute. Others use “Higashida”* Roots blower of 2.5 kw, outlet 2" and capacity of 3.5 cubic meters per minute.

Most of the hatcheries are located in remote places where the electricity is not available. For electric power they have their own generators, which varies from 2 K V A up to 20 K V A. Each hatchery at least has 2 generators, which run alternately every 8 hours.

Small water pumps of 2" outlet with electromotor or with gasoline engine are used to pump seawater.

Freshwater supply comes from shallow well as well as deep well. The water is pumped out with small pump or small automatic deep well pump. The freshwater is required for washing the tanks, laboratory equipment or for daily purposes of the workers.

The hatchery usually has a small laboratory for pure culture stock of diatoms used as food organisms and are also provided with some chemicals and a microscope.

Figure 3. Wooden box with plastic lining for larval rearing

^* Reference to trade mark does not imply endorsement

4. MANAGEMENT

The hatchery is usually managed by the family and some casual workers. In many cases one hatchery employs 8 persons, which consist of:
1 manager
1 driver
1 engine technician
1 plankton culturist
4 casual workers.

The technology of induced maturation, larval rearing, plankton culture and fry transportation is the same as the technology which has been developed by the Brackishwater Aquaculture Development Centre at Jepara (BADC). To support the success of the hatchery, the technicians from BADC Jepara, regularly give technical assistance to the hatcheries.

5. PRODUCTION

Since most of the hatcheries are newly built, the operation just started a few months ago and the annual production figures are not available yet. Anyhow, the hatcheries produced 100 000–200 000 PL per month. The hatcheries have no problems on the fry marketing, since the farmers are eager to buy shrimp fry from the hatchery, which purely consists of Penaeus monodon, while the fry from the natural stock might be mixed with Penaeus semisulcatus which would not grow well in the pond.

6. PROBLEMS

Some constraints to the private hatcheries so far are:

1. lack of Artemia cyst, it is expensive and difficult to get.
2. insufficiency of broodstock; some farmers have developed cooperation with the hatcheries by supplying broodstock while the hatcheries supply shrimp fry.
3. lack of skilled personnel — causing low survival rate.

4. lack of knowledge on pest and disease control.

7. PROSPECTS

The fish farmers now are eager to culture shrimp in their ponds, since the price is promising and the market demand is also increasing. There is no market problem for the crops, since the cold storages are well scattered in Indonesia. Supposing 50 percent of the total area of 180 000 ha are used for the culture of shrimp, with even a stocking density as low as 10 000 fry per ha, there should be made available 900 million of fry per year. According to the survey, the natural fry from the coastal areas in the country is about 400 millions a year, so there is shortage of at least 500 millions more of fry. In this case more small-scale shrimp hatcheries will still be needed.

8. DISCUSSIONS

Small-scale hatchery for penaeid shrimp is a new industry for Indonesia. There are still a lot of constraints in the technology of larval rearing that need solution.

The success of a hatchery depends on several factors:

1. suitable site selection
2. continuous availability of spawners
3. suitable water supply
4. available electrical supply
5. available skilled technicians

6. availability of Artemia cysts.

In this country, suitable sites for hatcheries are getting difficult to find. Industrial development, offshore oil drilling, advance agriculture farmers using more pesticides and increased sedimentation at shore from the rivers, result in only a few sites which can be suitable for hatcheries.

The spawners from the sea are available only at the beginning of rainy season (November-December) and at the end of rainy season (May-July). It is necessary that provision should be arranged for the hatchery to be in continuous production all year round. To overcome this problem, eyestack ablation of farm-raised shrimp has been initiated. But the hatcheries need bigger size shrimps (over 100 g each) which are rare in the farms which usually harvest during with size 10–20 pieces to a kilogram.

Lack of skilled technicians might be solved by conducting more training programmes on hatchery operations. On-the-job training can have more benefit than training courses on hatchery operation.

The supply of brine shrimp cysts still depends on import which takes time and the price is expensive. Since the shipping (even air parcel) and handling procedures at the Customs office take time, the hatching percentage of cysts usually gets poorer. Study on the possible culture of Artemia in tropical countries should be conducted to produce Artemia cyst. There are around 50 000 ha of ponds which are being altered into salt beds during the dry season. At least 50 percent of the total area might be used for Artemia culture.

Fig. 4. Distribution of shrimp/prawn hatcheries in Indonesia

Legend:

Mr - Macrobrachium rosenbergii hatchery

PM - BADC - Jepara - Penaeid + Macrobachium hatchery

- Small scale hatchery pilot project (penaeid)

(3) - Three private small-scale hatcheries (penaeid)

- One private small-scale hatchery (penaeid)

- Private small-scale hatchery under construction

- Hatchery for research purposes

WP 81 SPH CP-3

THE DESIGN AND OPERATION OF BACKYARD SHRIMP HATCHERY IN INDONESIA

by

Made L. Nurdjana, Budiono Martosudarmo and Sukotjo Adisukresno¹

ABSTRACT

One of the major problems in the establishment of shrimp aquaculture as an industry in Indonesia is the uncertain availability of fry. The supply of shrimp seeds for stocking the ponds, either from natural sources or from hatcheries is not yet adequate. Therefore, the building of new hatcheries to produce postlarvae is necessary. To help in easing up the big demand of shrimp fry for pond stocking, the BADC is now trying to simplify hatchery technology so that the farmers could practise it in producing postlarvae for their own stock.

The initial success in backyard shrimp hatchery experiments conducted by the BADC in Jepara clearly demonstrated this possibility. The design used, operational procedure as well as the result of this activity are described briefly in this paper.

1. INTRODUCTION

The principal constraint of extensive as well as intensive shrimp culture is the uncertain availability of shrimp fry. Collection of shrimp fry from the wild is dependent upon weather, seasonal distribution and other factors. For better shrimp culture management, continuous supply of fry will be required.

Natural supply alone could not fulfill the fry requirement for pond stocking. A survey of the shrimp fry potential showed that about 400 million of Penaeus monodon fry a year are available, but this amount is sufficient to stock only 20 000 hectares of brackishwater ponds. Whereas, if 50 percent of the total brackishwater ponds in Indonesia were used for shrimp culture even at low stocking density of about 10 000 fry ha crop, this means more than two billion fry should be made available per year. This required number will increase due to intensification and extensification of shrimp culture.

To meet the increasing demand of shrimp fry, the establishment of hatcheries to produce postlarvae is necessary. Since early 1978, the Brackishwater Aquaculture Development Centre (BADC) in Jepara. Indonesia has succeeded in inducing the farm-raised shrimp, Penaeus merguiensis and Penaeus monodon, to spawn in the broodstock tank by eyestalk ablation. The breakthrough give a new dimension in stimulating the expansion of shrimp culture programme in Indonesia. It is estimated that to meet the present demand at least 374 shrimp hatcheries with the production capacity of about 4 millions fry a year each will be required. The government hopes private investors could undertake this aspect of the industry with the government providing training programmes for the technicians.

Besides, to help the country solve the problem due to big demand of shrimp fry, the BADC is now establishing pilot projects to demonstrate simplified hatchery technology so that the farmers themselves may be able to produce their own postlarval stock.

This paper is an attempt to present the concise design as well as operation of small-scale backyard shrimp hatchery and also the result of a pilot activity conducted by the BADC Jepara in producing the shrimp larvae operated in a small-scale basis with emphasis on the technology which could be transferred to progressive shrimp farmers.

¹ Chief, Shrimp Breeding Section. Chief, Seed Production and Environment Division, and Director. Brackishwater Aquaculture Development Centre, Jepara. Central Java. Indonesia, respectively

2. THE REARING TANK

For the small-scale backyard hatchery, some factors should be taken into consideration regarding the larval rearing tank as well as spawning and algae culture tank. The construction of these tanks should be simple and they should be cheap. But, it should be borne in mind that the tank material is not toxic to the larvae. Tank size that the tank material is not toxic to the larvae. Tank size especially for larval rearing should be more than 5-ton in size in order to maintain stability of water temperature. The ratio between larval rearing tank and algal culture tank is about 10 to 4 respectively, in order to have enough food for the larvae.

Our study at Jepara suggested the use of plastic-lined wooden tank as rearing tanks. The tank is made of wooden boards lined with plastic sheet to retain the water. The thickness of the plastic is about 0.30 mm. The tank size for larval rearing is about 4.0 × 4.0 × 0.6 m. With this size, the water temperature fluctuation is around 26° to 30°C. The tank can be set on any clean level ground without cement base or soil compaction. According to experience, this tank could last for about 4 years, but the plastic sheet should be changed every two years.

3. REARING MEDIUM

To test whether the culture technique could be applied at any place where the saltwater is available, the BADC at Jepara has succeeded in using saltwater obtained directly from the shrimp pond for larval rearing medium. Before being used, the water was filtered through a 100 micron nylon mesh filter. If the water is still turbid, it can be left to stand for two days to allow the sediment particles size smaller than 100 micron to settle down on the bottom. Siphoning should be made to remove the sediment from the bottom.

The Jepara study has also shown that the use of clean seawater will produce better survival rate. But, as usually, clean seawater is difficult to get near inhabited residences, special vehicle to transport the seawater will be needed. This will increase the production cost of the fry. Therefore, the use of pond water is suggested, provided it is free from pollution and the salinity is about 30 ppt.

4. AERATION

There are several portable air pumps that can be used for small-scale backyard hatchery. The experiment at Jepara used simple aquaria aerators with both electric and battery powers. For tank size of about 16 m² eight aerators were used. Each aerator was provided with two airstones. Since we experienced that aquaria aerator will not last long, the use of portable compressor equipped with electromotor is advisable.

5. THE SPAWNERS

The gravid females for the small-scale backyard hatchery can be obtained either from wild spawners caught from the sea or pond-grown ablated spawners. Since the availability of wild spawner is unpredictable and the cost is high, the backyard hatchery will depend primarily on induced-matured spawners.

Since 1978, we have been successfully using the gravid females through induced maturation by eyestalk ablation. The broodstock were obtained from farm-raised shrimps. They were ablated and kept in the maturation tank until the gonads develop the stages III. Spawner sizes were about 80–100 grams. The fecundity varied according to the size of the spawners. The gravid females were transferred into a wooden boxes which served as spawning tank; the hatched eggs or nauplii are then removed to the larval rearing tanks the following morning. During spawning, the aeration was reduced to about one liter per minute and the tank surface should be covered with bamboo matting to reduce the light.

6. FEED AND FEEDING

Like other live animals, feeds and feeding have significant effect on growth and survival rate of shrimp larvae. Regarding the development of small-scale backyard shrimp hatchery the effect of feeds and feeding on growth and survival rate of P. monodon larvae has been studied. Feeds and feeding tests done at the Jepara Centre were divided into three groups:

1. Treatment A, fed with Skeletonema sp., Tetraselmis sp., Artemia nauplii and soybean curd.
2. Treatment B, fed with Skeletonema sp., Tetraselmis sp and soybean curd.

3. Treatment C, fed with soybean curd and pellets only.

Live food used in this experiment were separately in wooden tanks with size 1.0 × 1.0 × 0.60 m. Skeletonema sp and Tetraselmis sp were given during zoea to mysis stages. Since, Tetraselmis culture is quite easy and simple medium can be used (based on urea and TSP or triple superphosphate which are available locally), the backyard hatchery system should depend more on this species. Moreover, the culture of Skeletonema sp is quite difficult even at laboratory scale. The algae were transferred directly to the larval tanks after the population of the algae culture attained 3 million/cells/ml for Skeletonema sp and about 800 000 cells/ml for Tetraselmis sp. The density of algae in the larval tank during zoea stage is about 10 000 to 20 000 cells/ml while in the mysis stage about 20 00 to 30 000 cells/ml. Artemia nauplii was given after the larvae reached postlarval stage. In the third trial, the pellet used of about 100 micron in size, contained protein of about 30 percent. Soybean curd (tahu) was given in various sizes according to the larval stage as shown in Table 1. Soybean curd and pellet were given five times a day at 07 00, 12 00, 16 00, 19 00 and 22 00 hours.

7. WATER QUALITY MANAGEMENT

Considering the location, facilities and operation of backyard shrimp hatchery, it is necessary to develop larval culture technique without water changing during the larval rearing cycle. This was proved by the Jepara study which started in July 1979. To keep the water in good quality for the larvae, siphoning the bottom of the tank to remove leftover food and other dirt were made starting from Mysis III. On many occasions, siphoning have been made since early Mysis I according to the water quality. Besides that, the tank surface was covered with bamboo matting in order to reduce light intensity (Fig. 2). Experience showed that if the illumination is too bright, diatom blooms will occur. Diatom blooms were always followed by bacterial blooms, and bacterial blooms usually result in high mortality.

8. 3RESULTS AND DISCUSSIONS

The results of the backyard shrimp hatchery experiment at Jepara proved that this hatchery system can be introduced and might be profitable for the farmers. From seven trials, about 272 000 postlarval shrimp, age PL-9 were produced. The results are given in Table 2. The average survival rate was 18.6, 7.6 and 10.7 percent in treatment A, B and C, respectively. Most of the high mortality which occurred during development stage from nauplius to zoea stage was due to fungus disease caused by Lagenidium sp. The infection can be reduced to some extent by introducing malachite green at about 0.2 ppm. The use of treflan as fungus control agent has not been successful in the centre.

It can be seen that even if the rearing medium utilizes raw pond water, this could be used for spawning the penaeid shrimp and rearing through its larval stages. The survival rate from Mysis III to PL-9 is about 67.5 percent if the Artemia nauplii was given after the shrimp larvae reached the postlarval stage. The results in treatment B and C suggested that the shrimp larvae may be produced through the stage that is suitable for pond culture without giving Artemia nauplii. The survival rates from Mysis III to PL-9 were 29.8 and 35.2 percent in treatment B and C respectively. The survival rate could be improved to some extent if the density of the shrimp larvae in the rearing tanks is thinned out so that it does not exceed 20 000 pieces per m³ of rearing water.

As described in earlier Section, the method of larval culture used in this experiment was simple. It could be absorbed easily by progressive farmers. For spawners, this could be supplied directly by the government agency, like the BADC in Jepara or other similar centres as well as private hatcheries which have enough facilities in producing gravid females. It could be supplied either as gravid females or as eggs that are newly-spawned and ready to hatch out.

Due to the possible stress during handling and transporting the spawner, it may be more practical if the shrimp were spawned at the Centre first and later only the newly spawned eggs were given out to the farmer. Besides, the farmers need not have spawning tanks and it is assured that they will get the shrimp eggs that are already fertilized. Moreover, the Centre also can retain the spawners for re-use in subsequent period.

Experiments on egg transportation have been made. About 400 000 eggs were placed in two small plastic pails. Each pail was filled with 20 liters of seawater and aerated with small aquarium compressor. The trip took about 3 hours from Jepara Centre to one of the local hatcheries (Sluke hatchery) where the eggs were reared up to postlarvae. Further retention of the eggs for three hours was made as experiment. The plastic pails with shrimp eggs inside were held with minimal aeration during transportation. Result of this experiment showed that all of the eggs remained in good condition. The hatching rate was not affected by 6 hours of retention.

From economic point of view, it could be seen from Table 3 that even with only one batch the production could compensate the inputs. Disregarding the price of the spawner that the farmer might have to buy from the Centre in subsequent period, the farmer could have profits of about Rp 1 003 000.00* per seven months representing over 150 percent profit from the investment.

CONCLUSION

With the simple technique of hatchery management developed, small capital investment required and promising income expected by the operators, this would make backyard shrimp hatchery system acceptable to the farmers.

Since the induced maturation of P. monodon in a small and shallow tank is still doubtful, the availability of gravid females would become a major problems in introducing the small-scale backyard shrimp hatchery to the farmers. Therefore, the gravid females should be supplied by bigger hatcheries either private or government which have enough facilities to produce a member of spawners.

^* 1 US $ = Rp 630.00

Table 1.

Size of tahu particles given according to the stage of shrimp larvae

Table 2.

The survival rate of the larvae during the rearing periods

Treatment A. Fed with Skeletonema sp, Tetraselmis sp, Artemia nauplii and soybean curd
Treatment B. Fed with Skeletonema sp, Tetraselmis sp, and soybean curd
Treatment C. Fed with soybean curd and pellets

Table 3.

Inputs and outputs for the small-scale backyard penaeid shrimp hatchery after seven month operations

Fig. 1. Set-up of spawning/hatching/larval rearing tank

Fig. 2. View showing backyard shrimp hatchery unit in actual operation

WP/81/SPH CP-4

RESEARCH PROGRAMMES ON SHRIMP HATCHERIES IN INDONESIA

by

Fuad Cholik and Rustami Djajadiredja¹

1. INTRODUCTION

Shrimp is one of the important export commodities of Indonesia. Statistical data of the Directorate General of Fisheries indicate that during 1970 and 1979, around 50 to 63 percent from total Indonesian fishery exports consisted of shrimp. In 1979, the volume of shrimp exported from the country amounted to 34 200 metric tons valued at US $198.8 million. The volume may decrease by 10 500 metric tons due to the issuance of Presidential Decree No. 39/1980 which reduced the operation of trawlers in Indonesian waters.

Among efforts to overcome the decrease, intensification and extensification of around 131 000 hectares of shrimp ponds have been programmed by the government up to 1983. To ensure seed supply for the programme (around 1 500 million fry) 374 units of small-scale hatcheries will be needed (Anonymous 1980).

To ensure success of the programme, support from fishery research is necessary.

Research on shrimp breeding in Indonesia was started in 1970 in Ujung Pandang, South Sulawesi province by the Inland Fisheries Research Institute. The results, along with the insufficient supply of seed from natural sources, stimulated the establishment of a national research centre for shrimp at Jepara in 1974 and another two hatcheries, one at Sluke, Central Java and the other in East Java at Probolinggo. A private hatchery was also established at Bone in South Sulawesi in 1972.

Though, the Centre and hatcheries produced shrimp fry, the production was very low and their operation was uneconomical. Two major problems were encountered in their operation, namely lack of gravid females, especially Penaeus monodon, and low survival rate of the larvae.

To overcome the problems, starting in 1975 research on shrimp breeding was focused on induced maturation and improvement of larval rearing techniques. Nurjana, et al (1979) reported that the first experiment on induced maturation in this country was done by Cook in 1974 on Metapenaeus brevicornis. This was continued by Alikunhi in 1975 on P. merguiensis and P. monodon. Other experiments with mass production of matured females was done by Nurjana, et al (1976). Improvement of larval rearing techniques has been achieved in Indonesia after the breeding experiment of P. merguiensis by Nurjana, et al (1976) and P. monodon by Poernomo, et al (1980). At present some private small-scale hatcheries have been established in Java and started producing shrimp fry.

The development of shrimp hatcheries in this country is not without constraints. Some technical and socio-economical problems still exist that need solution. For this reason research programmes have been prepared for the next 5 years.

¹ Head, Research Results Dissemination Division, and Senior Scientist, respectively. Central Research Institute for Fisheries, Jakarta, Indonesia

2. RESEARCH ACHIEVEMENT

2.1 Gonadal maturation

So far, research done under this topic in Indonesia was just limited only to induced maturation by eyestalk ablation technique. No work has ever been done on other methods, such as light manipulation, feeding, etc.

Two species were used in the experiments, namely P. merguiensis and P. monodon. The experiments and its results may be briefly discussed as follows:

P. merguiensis mature more easily by eyestalk ablation as compared to P. monodon. Ablated females of P. merguiensis were found matured in aquarium, pool and holding tanks (Alikunhi, et al, 1975), while Nurjana, et al (1980) stated that the size of tank influenced significantly the success of maturation. Furthermore, he reported that mating process was difficult in small size tank of 0.5 to 8.0 tons. He suggested to use big tank of 60 tons. Cholik (unpublished) reported the success of maturation of P. merguiensis in tanks of 1 to 6 m³. P. monodon may also mature in relatively small tanks of 3 to 8.5 m³ as was reported by Poernomo (1980). However, he further stated that water depth played important role in the mating process. He suggested water depth of more than one meter was necessary for successful impregnation of females. This, confirmed the finding of Nurjana, et al (1980).

The size of shrimp used for the experiment varied greatly. The smallest size of female of P. merguiensis for eyestalk ablation was 9 g and 28 g (Alikunhi, et al, 1975). Poernomo, et al (1980) reported that in his experiment the matured smallest specimens of female P. monodon was 32 g. Poernomo, et al (1980) used 1:1 male to female ratio stocked in broodstock tank, and Nurjana (1980) recommended 1 to 1 or 3 to 2 ratio.

The experimented shrimp were fed with various types of feed. Alikunhi, et al (1975) and Nurjana, et al (1976) fed the shrimp with frozen mysids (Mesopodopsis sp), while Poernomo, et al (1980) used fresh squid meat, cockles (Anadara granosa) and artificial diet. The feeding rate applied was 15 to 20 percent of body weight per day.

2.2 Larval rearing

Experiments on larval rearing were conducted at Ujung Pandang, Jepara and Ancol, Jakarta. Three shrimp species were tried at Ujung Pandang, namely, P. merguiensis, P. monodon and P. semisulcatus, while at the others only P. merguiensis and P. monodon.

From the experiments, it was seen that two techniques of larval rearing can be adopted. In the first technique, spawning and rearing were conducted in the same tank, while in the second, these were done in separate tanks. The tanks used for the first technique varied in size. Cholik (1973) and Nurjana, et al (1976) used tanks of 12 tons and 1.5 to 60 tons, respectively. In the second technique, the size of tanks were smaller and their bottom shape was conical. Poernomo, et al (1980) and Yunus, et al (in preparation) used tanks of 50-liter, 500-liter and 800-liter.

In both techniques, water change was done after zoea stage at the rate of one fifth to one third of water volume per day. Artificial feed was also given as supplement, usually at mysis stage. No Artemia was fed to the larvae in both techniques. Natural food was normally available in the water fertilized with KNO₃ and K₂HPO₄ to stimulate their growth (Cholik, 1973) or stocked in the rearing tank for mass culture. These, consisted of diatoms, Tetraselmis and rotifers (Poernomo, 1980).

Cholik (1973) harvested the postlarvae of P. merguiensis at PL 12 to PL 17. He reported average production range of 0.5 to 1.7 PL liter of water and survival rate at 1 to 4.7 percent with highest value of 7.88 percent. Cholik (unpublished) also reported production of 2 PL (PL 12 to PL 17) of P. semisulcatus and 3.6 PL of P. monodon (PL 12 to PL 17) per liter of water. Nurjana, et al (1976) harvested P. merguiensis mostly at PL 3 to PL 5. At this stage, he produced 0.75 to 20 PL per liter of water and achieved survival rate ranging from 3.0 to 71.2 percent with an average of 13.9 percent. Poernomo, et al (1980), in his experiment on P. monodon using conical fiberglass tank of 50-liter capacity have attained higher production range of 42 to 170 PL 5 to PL 7 per liter of water and 54 to 108 PL 5 using 500-liter tanks. The survival rate ranged from 27 to 88 percent.

3. CONSTRAINTS

The success of experiments on gonadal maturation by eyestalk ablation is a great contribution to shrimp culture development. It makes hatchery operations more feasible and in turn ensure seed supply for culture. However, failure in ovarian development of ablated P. monodon is also often experienced. This, based on our experience at Ancol (Jakarta) may be due to great fluctuation of water temperature or other unfavourable water conditions and diet composition. We often found that the development of ovary of ablated P. monodon reached up to Stage II only and later reabsorbed. Sometimes spawning occured, but the eggs were unfertilized.

In larval rearing, it seemed that remarkable improvement has been achieved. This, may be due to harvest at earlier stages (PL 3 to PL 7). At later stages recorded mortalities were still high. For pond stocking, PL 3 to PL 7 are still too small. So, to avoid mass mortality in ponds, special nursery techniques will be necessary. Another reason for low survival is insufficient supply of natural food. Among the food, Artemia may be the best. However, this item is very expensive. The culture of this food organism should be promoted.

High production of postlarvae has also been achieved by the use of conical tanks and more stable water temperature levels (Poernomo, et al 1980). However, since the result derived from experiment using small tank (50 l), this should be further verified by testing in bigger tanks of 1.0 to 2 tons.

Another point to be considered in the application of hatchery techniques is site selection. Experience indicated some of the existing hatcheries were mislocated. Problems encountered were pollution, low salinity, turbidity and prevailing wind. Moreover, it was experienced also that most site suitable for hatcheries are not suited as sites for brackishwater ponds. Sometimes, the distance of a hatchery is far from pond sites which will increase production cost.

Operational planning of a hatchery should also consider the schedule of culture activities in the region. In Indonesia, pond preparation starts at the beginning and the end of dry season, that is on March to April and August to September. Stocking the pond usually starts April-May and October-November. So the highest demand coincides with these periods. This, will limit hatchery operations up to 6 months only. Means to absorb more of the expected hatchery production should be solved, otherwise the high investment in such a limited enterprise may be questionable. A small-scale hatchery that may be financially adoptable to small-scale farmers is one that takes into consideration the above circumstances.

So far in Indonesia P. monodon is the only shrimp species cultured with intentional stocking. It is believed that the culture of P. merguiensis and P. indicus is difficult, though these species grow wild in ponds with M. ensis and M. brevicornis. Sometimes small-size P. semiculcatus may also be observed in ponds. Breeding technique of these species are not known. Efforts to promote the culture of these species may stimulate the establishment of hatcheries to produce fry of these shrimp species.

Hatchery design is another area of research. Experience obtained from our giant freshwater prawn small-scale hatchery and Pasarmiggu, Jakarta indicates that a hatchery with transparent roofing and without wall structure affects the growth and survival of larvae. This may be due to too strong light intensity and great fluctuations of water temperature.

Mass mortality of larvae due to Lagenidium sp at the hatchery at Jepara has also been reported by Sunaryanto and Mintardjo (1980). The report indicated 75 to 100 percent mortality of larvae. Research in this field should be strengthened to avoid great loss of hatchery crop.

To establish a small-scale hatchery of around 6 to 8 million fry production capacity requires around 50 million rupiahs (+ US $80 000) for investment and 10 million rupiahs (US $16 000) operating cost. This amount is beyond the financial capability of most farmers. A less expensive smaller design that can be economically viable should be determined.

Breeding technique of shrimp and prawn is hardly known to most farmers. To promote the development of hatcheries of the cultivable species requires training for capable technicians.

4. RESEARCH PROGRAMMES

Research programmes on shrimp breeding is oriented to the solution of the problems discussed in the previous section. These will involve the following research activities:

1. Gonadal maturation

   Research under this topic will consist of the study on the effects of light manipulation and feeding on ovarian development.

2. Mass culture of natural food organisms

   This research will emphasize on mass production of Artemia salina cysts.

3. Larval and postlarval feed and nutrition

   The objective of this study is to obtain sound feed formulation for larvae and postlarvae.

4. Study on ecological requirements of larvae and postlarvae

   This will include light intensity, temperature, pH and metabolites.

5. Nursery technique for early postlarval stage

   This will be done to obtain nursery techniques of early postlarval stage (PL 3 to PL 7) produced by hatcheries to get bigger size of fry more suitable for pond stocking.

6. Site survey

   This activity is aimed at supporting the national shrimp development programme in selecting suitable sites for the proposed hatcheries.

7. Water filtration

   The use of filters based on SWS-type units for clean water supply for small-scale hatchery at pond site should be investigated.

8. Simplification of design

   Study on hatchery design to reduce investment and operating cost.

9. Other activities

   Other culture research activities that support hatchery development programme.

10. Diseases

    Diseases of larvae and postlarvae should be undertaken to effect prevention as well as control.

11. Socio-economic studies

    The results of research should be disseminated through demonstration in national and regional development centres and by the conduct of training courses to extension workers and fish farmers.

REFERENCES

Alikunhi, K.H., A. Poernomo, S. Adisukresno, M. Budiono and S. Busman. 1975 Preliminary observation on induction of maturity and spawning in Penaeus monodon Fabricius and Penaeus merguiensis de Man by eyestalk ablation. Bull. Shrimp Cult. Res. Cent. I(1): 1975: 1–11.

Cholik, F. 1973 Experiment on shrimp (Penaeus merguiensis de Man) propagation under controlled condition. Research Report of the Inland Fisheries Research Institute. Bogor, Indonesia (in Indonesian).

Cholik. F. (Unpublished). Report on the termination of assignment in Vietnam. Report submitted to FAO-Rome.

Nurjana, M. and W.T. Yang. 1976 Induced gonad maturation, spawning and postlarval production of Penaeus merguiensis de Man. Bull. Shrimp Cult. Res. Cent. II(½): 177–186.

Nurjana, M., Anindiastuti and S. Busman. 1980 Production of matured females of penaeid shrimp. Manual on shrimp hatchery, Directorate General of Fisheries, Jakarta (in Indonesian).

Nurjana, M., S. Adisukresno and Anindiastuti. 1979 Mass production of gravid females through induced maturation by unilateral eyestalk ablation. Discussion forum of shrimp specialist of Indonesia, Bogor (in Indonesian).

Poernomo, A. and M. Yunus. 1980 Gonadal maturation of tiger prawn, P. monodon by unilateral eye-stalk ablation and larval rearing using water circulation system. Bull. Fish. Res. I:76–86.

Sunaryanto and K. Mintardjo. 1980 Diseases and its control Manual on shrimp hatchery. Directorate General of Fisheries, Jakarta (in Indonesian).

Yunus, M., Fuad Cholik and T. Daulay. (in preparation). Larval rearing technique of Penaeus merguiensis in conical fiberglass tank. Bull. Fish. Res. Indonesia (in Indonesian).

Anonymous. 1980 National programme on shrimp development. Workshop on shrimp hatchery. Jakarta, Indonesia (in Indonesian).

WP/81/SPH/CP-5

RESEARCH PROGRAMMES ON PRAWN HATCHERIES IN INDONESIA

by

Asmin Ismail and Fuad Cholik¹

1. INTRODUCTION

Research on breeding of giant freshwater prawn (Macrobrachium rosenbergii) by the Inland Fisheries Research Institute has been done sine 1973 (Suyanto, et al, 1974). Until 1979 research progress was very slow, though relatively high production was achieved by the adoption of “green water” method.

Two major constraints caused the slow development of giant freshwater hatcheries in Indonesia, namely high investment cost and low fry demand due to undeveloped pond culture techniques.

Research to develop small-scale hatcheries has been done since 1979, while experiment on pond culture is still being programmed. The results are promising.

2. RESEARCH ACHIEVEMENT

Remarkable improvements in larval rearing of giant freshwater prawn was achieved in 1979 after the adoption of rearing techniques used by AQUACOP (1977) with necessary modifications by the Inland Fisheries Research Institute. In this technique instead of “green water”, clear water of 8 to 12 ppt is used as culture media. Before being used, the clear water is aged in a reservoir for 24 hours, treated with chlorine at 1.5 ppm and aerated.

Another characteristic of the technique is the larval rearing in tank which is conical in shape. The tank is placed in another bigger tank filled with water and heated with submerged electrical heater of 350 watts. This, avoids water temperature fluctuation in the larval rearing tank. In our experiments, using 50 liter larval rearing tank placed in bigger water filled tank of 500 liter, water temperature fluctuated only 2°C per 24 hours. The larval tank is green in colour and made of fiberglass.

First stage larvae produced from hatching tank were stocked at the rate of 100 to 200 larvae per liter. The larvae were fed with artificial feed, finely ground snake-head meat and brine shrimp, three times per day. The Artemia was given in the late afternoon, after siphoning of the other food remains and water addition.

Results of 5 series of experiments indicate high larval survival rate and juvenile production. At stocking rate of 100 larvae/l, the production ranging from 45 to 85 juveniles/l were obtained or a range of survival rate between 45 to 84.5 percent. Duration of rearing range between 35 to 49 days. At stocking rate of 200 larvae/l, the production and survival rate range were 93 to 169 juvenile/l and 46.5 to 84.6 percent survival, respectively. The rearing period ranged from 35 to 42 days.

Using rearing tank of 500 liter did not show any significant difference in larval production and survival rate. At stocking density of 100 larvae/l, the production achieved ranged between 51 to 72 juveniles/l or 51.3 to 72.1 percent survival. At 200 larvae/l, the production varied between 98 to 125 juveniles/l or 48.8 to 62.5 percent survival. Rearing period of the larvae was 42 days.

¹ Research Staff and Chief Research Results Dissemination Section, respectively, Central Research Institute for Fisheries, Agency for Agricultural Research and Development, Jakarta, Indonesia

The above larval production and survival rate is much higher as compared to the result of our former experiments adopting the “green water” technique developed by Fujimura (1966). Production of juveniles achieved by the application of “green water” technique was only 4 to 10 fry/l or even sometimes less (Ismail, et al, 1977). Two major problems were noticed from the experiment, that is the difficulty in the preparation of “green water” and temperature fluctuations. Another disadvantage was the flatness of the larval rearing tank.

Average size of broodstocks used for the experiments was 50 grams. They were collected from our culture pond and stocked into spawning tank of 15 ton. Male to female ratio stocked was 1 to 3. They were fed with pelletized feed and fresh mollusk meat at 3 percent body weight per day. Prior to transfer of the spawners into hatching tank, they were desinfected by the 0.5 ppm malachite green method. This was done by placing five to ten spawners in 20 l malachite green solution for 15 to 20 minutes. During desinfection, the water was continuously aerated. They were rinsed in clear water after the desinfection process was finished.

3. DEVELOPMENT CONSTRAINTS

As a follow-up of the research results a pilot project of small-scale prawn hatchery has been established at our station at Pasarminggu, Jakarta. The establishment of the hatchery is for testing the research result in a commercial scale. Problems encountered are as follows:

1. Supply of Artemia

   From our experiments we may conclude that the use of Artemia in larval rearing will increase production of juveniles. Though, other live food such as Moina, Daphnia and Brachionus may also be used, yet they could not replace the Artemia. However, Artemia is very expensive. Present price of this item at local market is even as high as US $200/kg. Besides to get sufficient supply of good quality Artemia from the market is also difficult. Research on mass production of this food is urgently needed.

2. Hatchery design

   Hatchery with transparent roofing without wall structure seems not suitable for our country. In such condition, light intensity is too strong for the larvae and great water temperature fluctuation occurs.

3. High investment cost

   The cost to establish a hatchery with production capacity of 5 million fry per year is calculated at around 50 million rupiahs or about US $80 000. This, is beyond the financial capability of most farmers.

4. Skilled technicians

   Lack of skilled technicians is also another constraint for the development of small-scale hatchery.

4. RESEARCH PROGRAMME

Based on the constraints discussed in the previous section, research programmes for this commodity for the next five years will be as follows:

1. Broodstock quality improvement

   This will involve genetic study of specimens collected from various places throughout Indonesia and feeding trials.

2. Ecological studies

   These studies cover the effect of ecological factors such as light intensity, temperature to growth and survival of larvae.

3. Mass culture of natural food, with emphasis on the culture of brine shrimp.

4. Feed and nutrition of larvae and juveniles

5. Hatchery design to reduce investment cost

6. Diseases and parasites of larvae and juveniles

7. Site survey

8. Socio-economic study on small-scale hatchery

5. LITERATURE CITED

AQUACOP. 1977 Macrobrachium rosenbergii (de Man) culture in Polynesia. Progress in developing a mass intensive larval rearing in clear water. Eighth Workshop of Word Mariculture Society, Costa Rica, 10–13 January 1977.

Fujimura, T. 1966 Notes on the development of a practical mass culturing technique of giant prawn, Macrobrachium rosenbergii. IPFC (FAO) 12th Session, Hawaii.

Ismail, A. and Haniah H. Suharto. 1977 Manual of prawn hatchery. (unpublished).

Suyanto, R. and Rustami Djajadiredja. 1974 Preminery experiment on Macrobrachium rosenbergii. Research Institute for Inland Fisheries. Report No. 8.

WP/81/SPH/CP-6

STATUS OF SMALL-SCALE HATCHERIES FOR CULTIVABLE SHRIMPS AND PRAWNS IN MALAYSIA

by

Ong Kah Sin*

1. INTRODUCTION

1.1 Status of shrimp and prawn culture industry

The culture of shrimp (e.g. Penaeus monodon, P. merguiensis, Metapenaeus affinis, M. ensis) and prawn (Macrobrachium rosenbergii) in Malaysia is still not well-developed. Although shrimp farming by the tidal trapping method has been practised for many years, and small-scale prawn culture based on artificially produced prawn fry has been carried out since the early 60's, it is only quite recently that significant ventures in shrimp/prawn hatcheries and farms have taken place in Malaysia.

The total area of coastal ponds presently used for shrimp culture is estimated at less than 600 hectares, with an estimated production of less than 500 tons per year. Most of the ponds, especially traditional ponds, are located in Johore, while ponds based on hatchery-produced fry have recently been constructed in Kedah, Perak, Penang and Sabah. These ponds are still being operated more or less on a pilot scale at present, but in view of successful developments in shrimp culture elsewhere, and growing interest in shrimp and prawn farming, several fairly large-scale projects are expected to be undertaken in the near future.

For prawn culture, freshwater fish ponds are used, with the prawn included in the polyculture system. At present, there are some 6 000 hectares of freshwater ponds in Malaysia, but only a small portion has been used for prawn fish polyculture, and prawn monoculture is still in its early stage of development. With the recent and forthcoming setting up of prawn hatcheries, there will be considerable increase in the production of prawn juveniles, which is estimated at less than 10 million per year, at present.

1.2 General nature of hatcheries used at present

The shrimp and prawn hatcheries in Malaysia are generally located near the sea, thus obviating the need for transporting seawater. Freshwater is usually obtained from the public supply. Environmental control systems for optimum rearing conditions are lacking and thus hatchery operations are often affected by adverse weather conditions, especially during the rainy periods, when rearing temperatures can drop to 25°C.

1.3 The place of small-scale hatcheries in development and economy of country

The supply of shrimp and prawn juveniles from the wild is limited, and not dependable as a source of stocking material. The hatchery production of shrimp and prawn seeds is thus of utmost importance. In view of the wide distribution of shrimp and prawn ponds in the country, it is advantageous to have these hatcheries built in several convenient locations in the country, to facilitate the supply of seeds. Also, in view of the fledgling nature of shrimp and prawn culture in Malaysia, and the difficulty of obtaining adequate ‘wild’ spawners of some shrimp species (particularly, Penaeus monodon), it is considered that small-scale hatcheries are at this stage more practicable and appropriate.

^* Senior Fisheries Officer (Research) Fisheries Research Institute, (Fisheries Division, Ministry of Agriculture). Glugor, Penang, Malaysia

2. DESIGN AND CONSTRUCTION

2.1 Characteristics of sites suitable for hatchery project

The sites should be strategically located with regard to the supply of both seawater and freshwater, and public utilities. Both the quantity and quality of the seawater and freshwater must be first determined by the application of standard techniques. Although for small-scale hatcheries, the requirement of the site area is not large, it is desirable to have an adequate site area, and suitable ground conditions for the construction of some ponds for broodstock, and of some staff quarters within close proximity of the hatcheries. The sites should also be within easy reach of public utilities but be free from pollution.

2.2 Design

The design of hatcheries should be aimed at maximum productivity, and minimum costs of development and operations. Optimum environmental conditions, particularly temperature, and hatchery hygiene need to be incorporated in the hatchery design. For small-scale hatcheries, however, environmentally-controlled systems and expensive water supply and treatment systems would be precluded, but the provision of a hatchery building, with clear roofing, to house the rearing tanks, is considered a basic requirement. To maintain optimum temperature conditions, the hatchery should be enclosed and the larval rearing tanks should be at least 1 m³ in capacity, but not too large as to pose problems of adequate stocking or tank management; the size of larviculture tanks in Malaysia at present usually ranges from 2–16 m³. They are mostly rectangular or circular in shape, but recently round tanks with conical bottoms similar to those used in Tahiti (AQUACOP, 1977) have also been set up locally.

With regard to the design of the water supply systems, Ong, et al(1977) has reported it was not possible to set up the tube-well system in several instances; it is therefore necessary to rely on surface seawater, and the public water supply for freshwater. There should be separate reservoirs settling tanks for adequate supplies of both seawater and freshwater, and the seawater from the reservoir should be filtered through a sandgravel filter before use. Tests have also been carried out on the possibility of using the “SWS” system (Cansdale, 1979), to obtain pre-filtered seawater in a few localities on the West Coast of Peninsular Malaysia, but because of the rather muddy substratum in these test sites, the system could not be set up for any of the existing hatcheries.

The aeration system for hatcheries should be designed for non-stop operation although breakdowns of brief duration do not result in mass larval mortalities. The Roots-type blower has been found to give reliable service. In case of power failures, it is necessary to provide an alternative power source to run the airblower and other hatchery equipment.

2.3 Construction-materials and construction

Hatchery buildings are constructed of concrete and wood, roofed with a combination of corrugated asbestos sheets and clear greenhouse panels/plastic sheets, to provide the desired heating and lighting conditions.

The culture tanks are made of fiberglass or concrete. With the many fiberglass manufacturing companies already set up in the country, fiberglass tanks are now readily made available — according to the specifications required — and these tanks are preferred for larviculture in small-scale hatcheries. For broodstock maintenance, the larger, concrete tanks or earth ponds are generally used.

Water and aeration piping and valves are all of PVC or polyethylene.

3. OPERATIONS AND MANAGEMENT

3.1 Broodstock

For shrimp, gravid females are caught from the sea; while for the prawn, ovigerous females are obtained from both captive broodstock and from the wild.

3.2 Induced spawning methods

Preliminary experiments on gonadal maturation and spawning have been carried out on some shrimp species, particularly Penaeus monodon and P. merguiensis. Single eyestalk ablation was performed on wild-caught females immediately after their spawning in the hatchery,. and the females were then maintained in concrete hatchery tanks provided with a built-in subsand, air-lift filter system. The shrimp were fed fresh squid or cockle (Anadara granosa). So far, only a few of the eye-ablated females have re-spawned, and only a few viable eggs or nauplii were obtained; further work is required in this field in Malaysia.

With regard to the prawn, spawning takes place readily in captivity, and no problem is encountered in obtaining sufficient spawners for hatchery operations.

3.3 Rearing of eggs and hatchlings

For penaeid eggs and hatchlings, the rearing is carried out in seawater with a salinity of 28–30 ppt, pH of 7.8–8.5 and a temperature range of 26–32° C, and the water is vigorously aerated.

For the prawn, the berried females are usually first kept in low salinities of 4–8 ppt and then when the larvae are hatched, the salinity is increased to 12–16 ppt. Both “green water” and clear water systems are used for the larval rearing. The water salinity is gradually reduced as metamorphosis progresses.

For larval shrimp and larval prawn rearing, there is no fixed schedule for water change; usually some partial water change is effected daily after first siphoning out the bottom wastes and only when conditions appear fouled that a complete water change is carried out — through screens of suitable mesh to prevent the larvae from being drained out.

3.4 Feed and feeding

For shrimp larviculture, cultures of diatoms (mainly Chaetoceros calcitrans, and mixed species) are produced for feeding the protozoeae, while newly-hatched Artemia nauplii are provided for feeding the mysis larvae and also the early postlarvae. Rotifers grown in “green water” are often collected as a supplemental feed for the mysis larvae. For the postlarvae, shredded cockle (Anadara granosa) is the main food given.

For prawn larviculture, newly-hatched Artemia nauplii are given throughout the larval period, usually as the last feeding for each day, with screened fish flesh powdered milk-egg custard and shredded cockle/clam given after the first week. Juveniles are fed shredded cockle and chicken feed, in the form of crumbles.

3.5 Diseases and control of the causes of mortality

Diseases caused by bacteria (e.g. Leucothrix), fungi (e.g. Saprolegnia) and by protozoans (esp. Zoothamnion) are commonly encountered in hatchery operations. Other causes of mortality include proliferation of small hydromedusae and infestation of larviculture tanks with aquatic insects such as the water boatmen (Micronecta sp), and too sudden change of rearing water or rough handling of larvae/postlarvae in some cases.

Hatchery hygiene needs to be well-maintained at all times, as “prevention is better than cure”. Also, many of the antibiotics and other drugs reported to be effective cures for larval diseases are rather expensive and not easily available locally. When larval mortalities are expected, or already occur, treatment with formalin at 250 ppm for approximately one hour is often quite effective.

To prevent mortalities due to equipment or power failures, and also for security reasons, it is advisable to have a watchman on duty during after-hours.

3.6 Collecting, handling, transport and marketing

Postlarvae/juveniles produced in the hatcheries are collected with fine-mesh nets and packed in polythene bags, approximately half-filled with water (6–7 liter) and subsequently inflated with oxygen and securely tied with rubber bans. Usually about 2 000 juveniles are packed in each bag. The juveniles are then transported by van to the culture ponds, or the bags are first placed in paperboard cartons, if transportation is to be carried out by air.

4. PROBLEMS AND CONSTRAINTS

The more general problems affecting the overall aquaculture industry in the region, as have been indicated by Ling (1973), also impede the development of small-scale hatcheries for cultivable shrimps and prawns. More specifically, the major problems are considered to be:

1. the difficulty of obtaining sufficient numbers of gravid females of shrimp (particularly Penaeus monodon), as wild caught spawners are expensive and not available throughout the year, and the techniques for the hatchery maturation and spawning of shrimp has not been adequately developed locally;

2. the lack of a good and yet inexpensive larval feed that can reduce or even eliminate the great dependence on Artemia for hatchery operations; and

3. the lack of skilled manpower of the right calibre that can ensure the success of hatchery operations.

5. RECOMMENDATIONS AND PROGRAMMES

Appropriate efforts should be made towards ensuring an adequate supply of gravid females of shrimp for hatchery operations. Priority attention should be directed at developing the techniques for the maturation and spawning of Penaeus monodon under pond or hatchery conditions, so that gravid P. monodon can be easily available as berried females of Macrobrachium rosenbergii.

Research and development of artificial feeds for shrimp and prawn hatchery operations should be actively pursued, as Artemia is expensive and needs to be imported, and the cultivation of natural larval food organisms is often inadequate to meet hatchery requirements.

REFERENCES

AQUACOP. 1977 Production de masse de post-larvae de Macrobrachium rosenbergii (de Man) en milieu tropical: unite pilote. 3rd Meeting of the Working Group on Mariculture, Brest, France, May 10–13. Actes de Colloques du CNEXO, 4:213–232.

Cansdale, G.S. 1979 Low-cost water filtration system. Manila, South China Sea Fisheries Programme. SCS/79/WP/80.

Ling, S.W. 1973 Status, potential and development of coastal aquaculture in the countries bordering the South China Sea. Rome, FAO. SCS/DEV/ 73/5.

Ong, K.S., F.O. Ng and Y.K. Wong. 1977 Experiences and problems in the design and operation of a Macrobrachium hatchery. SCSP-SFDC/77/AEn/CP-32.

WP/81/SPH/CP-7

DEVELOPMENT PROGRAMMES ON SHRIMP AND PRAWN HATCHERY OF THE MALAYSIAN FISHERIES DEVELOPMENT AUTHORITY (MAJUIKAN)

by

Banchong Tiensongrusmee¹

INTRODUCTION

The Fisheries Development Authority of Malaysia (MAJUIKAN) is a government agency charged with the task of accelerating development of fisheries enterprises in the country. During the Third Malaysia Plan (1976– 1980) the promotion of aquaculture amongst low-income agricultural groups was emphasized, and aquaculture development is given even higher priority in the Fourth Malaysia Plan (FMP, 1981–1985). Under the FMP, the Aquaculture Division of MAJUIKAN is expected to receive allocation of approximately M$35² million for developing both large-scale aquaculture to supplement sources of fish production with a view of increasing protein intake and creating employment opportunities.

In line with the FMP, about 50 ha of a large-scale shrimp pond in the villages of Sungai Merbok of Kedah State, Sungai Pelepas and Sungai Dangga in Johore are being developed. Besides these big-scale projects, the family-concept unit of shrimp culture programmes are also planned at Pulau Penang of Kedah and Sungai Pelepas of Johore with a total area of 100 ha for 100 families.

Based on the brackishwater projects of MAJUIKAN under the FMP, about 1, 3, 6, 15 and 20 million of postlarval penaeid shrimp are required in 1981, 1982, 1983, 1984 and 1985, respectively.

For freshwater prawn, about 1, 3, 5, 6 and 10 million of juveniles/year are also required for Puchong fishfarm in Selangor and Tanjong Tualang Project in Perak in 1981, 1982, 1983, 1984 and 1985, respectively. With a view to support the requirement of the MAJUIKAN's pond projects the following hatcheries are planned and established.

Table 1. Penaeid shrimp postlarvae required under the FMP of MAJUIKAN's pond projects (million)

Table 2. Macrobrachium juvenile prawns/required under MAJUIKAN pond projects (million) under FMP

1 Senior Aquaculturist Team Leader, Institutional Support for MAJUIKAN Aquaculture Development Project (FAO/UNDP MAL/79/018) Tingkat 7, Wisma PKNS, Jalan Raja Laut, Kuala Lumpur, Malaysia

2 MS = US $1

1. Tanjong Dawai temporary hatchery

The hatchery was established in 1979 with a view of testing the economic viability of production of seabass and penaeid shrimp fry. The hatchery is also used for training MAJUIKAN personnel in preparation for the Merbok hatchery that is expected to be completed in 1983. At present this temporary hatchery is under operation with the technical assistance of FAO/UNDP/ MAL/79/018.

The seawater as well as the freshwater systems of the temporary hatchery are not good enough to allow the hatchery to operate with as high efficiency as required. The existing systems only allow the hatchery to produce ten spawners of shrimp per batch. The hatchery does not have a proper water filter system, no reservoir tank, no gravity tanks and no proper piping system.

Under the technical assistance programmes, the hatchery is scheduled to produce 0.6 and 2.0 million of penaeid shrimp postlarvae in 1982 and 1983 respectively as shown in Table 3.

The hatchery will be subsequently shifted to the Merbok hatchery after 1983.

Table 3. Expected production of Tanjong Dawai hatchery from 1982–1983

2. Sungai Merbok hatchery

To meet the need of penaeid seed requirement of MAJUIKAN pond projects as shown in Table 1, the Sungai Merbok hatchery is being planned and constructed. The hatchery is located just opposite the Tanjong Dawai temporary hatchery. The hatchery is designed not only for penaeid shrimp, but it is also planned to produce seabass and grouper fry for the cage culture project as well. The hatchery is now under construction with the budget of M$2.4 million. The construction is expected to be completed in 1983. The hatchery is planned to produce Penaeus monodon postlarvae PL-25 about 4.5, 5.4 and 6.3 million in 1983, 1984 and 1985, respectively. Besides P. monodon fry, the hatchery also plans to produce P. merguiensis, seabass and grouper fry at the amount given in Table 4.

Table 4. Expected production of Sungai Merbok hatchery from 1983–1985

3. Sepang Macrobrachium hatchery

The hatchery was established in Sepang, Selangor with a view of supplying Macrobrachium seed to MAJUIKAN's freshwater pond projects. A hatchery building size of 7.0 m × 30.0 m has been completed with working tables, chairs and cabinets. Thirty six circular concrete tanks of diameter of 1.5 m by 0.8 m high were completed. Two blowers of 1 hp capacity each and two generators (15 KVA, 7 KVA) were installed. Two fresh-water reservoirs of about 6-ton water capacity each and two seawater reservoirs of the same capacity were completed. The two water conditioning tank of 15 ton water capacity were also completed.

The hatchery is planned to operate 10 runs/year. According to the schedule, the hatchery will produce Macrobrachium juveniles about 0.1, 5.0, 8.0 and 10.0 million in 1981, 1982, 1983 and 1984, respectively. The production will be stabilized at 10 million/year after 1984.

Table 5. Expected production of Sepang Macrobrachium hatchery from 1981–1985

WP/81/SPH/CP-8

DESIGNS OF SMALL-SCALE SHRIMP/PRAWN HATCHERIES SUITABLE FOR DEVELOPING COUNTRIES IN SOUTHEAST ASIA: 1. BASED ON A MODEL DESIGN FOR A FRESHWATER PRAWN HATCHERY USED BY MAJUIKAN IN MALAYSIA

by

Banchong Tiensongrusmee¹

1. INTRODUCTION

The production of Macrobrachium under scientific control is initiated by Dr. Shao-wen Ling in Penang. Malaysia in the early 1960s. His work has generated worldwide interest, and many important developments have been subsequently initiated in many countries. In recent years, a considerable amount of new knowledge has been gained and encouraging progress made. This presentation is based on a model of small-scale Macro-brachium hatchery that is being constructed at Sepang, Selangor. The hatchery is designed and constructed under Malaysian conditions with a view of supplying the need of Macrobrachium juveniles for MAJUIKAN's freshwater pond projects.

2. DESIGN CRITERIA AND SPECIFICATIONS

The hatchery is planned to have a production of 5–10 million juveniles/year. The larvae are grown up to juvenile stage which takes about 30–45 days. One year can operate about 10 batches.

2.1 Size of the hatchery

About 5 ha is enough area for broodstock holding tanks, spawning tanks, larval rearing tanks, algal rearing tanks, algal stock culture room and offices (Fig. 1).

2.2 Water supply

2.2.1 Seawater

The seawater is ground water with the salinity of 18 ppt. Stainless steel pump with a capacity of 50 m³/min of seawater is required.

2.2.2 Freshwater

The freshwater is tap water of Sepang city. The water is conditioned in the storage tanks before use. The pH is adjusted down to 7–8 as those given in Table 1.

2.3 Air supply system

Three sets of air blowers are used. Each set has an output of 1 hp with a pressure of about 0.2–0.3 kg cm².

Carborundum grinding stones 9 cm long, 3 cm in diameter, hollow inside with an inside-well thickness of 0.5 cm are suitable. The airstones are used with 9 mm (inside diameter) plastic tubes and a heavy sinker tied at the neck of the airstones. This type of airstone may be used at a rate of one airstone per 5 m² of area. PVC pipes are preferred for air distribution lines.

Stoppage of aeration is fatal to the larvae, and sudden power failures can be disastrous. Therefore a relay warning system is going to be installed to notify the culturist of any stoppage of the aeration system.

2.4 Electricity

Supply of electricity is obtained from the National Electric Board (Lembaga Lectric Negara = LLN). Two generators with an output of 15 KVA and 7 KVA are installed.

2.5 Broodstock holding tank

Broodstock are obtained directly from Puchong fishfarm in Selangor. The berried females are kept in broodstock holding tank. The stocking rate is 5 spawners/m². Only gravid females with dark grey eggs are transferred into spawning tanks.

2.6 Spawning tank

To minimize the larvae of different stages in a rearing tank a spawning tank is specially designed. The tank is rectangular with size about 1.0 × 3.0 × 0.6m. The berried females with eggs of the same stage are placed in the tank. The larvae that hatch out on the same day are siphoned to the rearing tank.

¹ Senior Aquaculturist/Team Leader. Institutional Support for MAJUIKAN Aquaculture Development Project (FAO/UNDP/MAL/79/018) Kuala Lumpur Malaysia.

2.7 Larval rearing tanks

A 2-ton larval rearing tanks is made of concrete with conical bottom (Fig. 2). It is 1.5 m in diameter. The initial stocking rate for nauplii is 100 liter. The stocking density at the end is 40 liter.

2.8 Phytoplankton tank

About 10 circular tanks are required for phyto-plankton. The tank is flat bottom, 1-ton capacity with 1.5 m diameter, and 0.6 m height. The tanks are provided with aeration for efficient circulation and for keeping the organisms in suspension.

2.9 Water exchange filter

To prevent the loss of larvae during water exchange, a filter box with dimensions of 50 × 50 × 100 cm is used. The frame is constructed of stainless steel. Two layers of screening material are attached to the frame. The inside screen is with approximately 3.0 to 4.0 mm mesh openings to reinforce and support the outside screen. For the late mysis and postlarval stages, the outside screen of plankton net material has about 350 micron openings. For harvesting juveniles, the mesh opening of the outside screen is about 1 mm diameter to permit fast drainage without much clogging.

3. PRODUCTION REQUIREMENTS

3.1 Spawner

The survival rate from larval stage to juvenile stage is about 40 percent. The hatchery is operated with 10 runs year. During the first two weeks, the larvae are reared in green water, and shifted to clear water after the second week. The spawners are obtained from the Puchong fishfarm.

3.2 Water quality

The water quality in the rearing tanks has to be monitored and should satisfy conditions as those given in Table 1.

3.3 Feed

Feeds are given five times a day at 08 00, 10 00, 14 00, 16 00 and 21 00 hours. The feeding programme is as follows:

4. COST OF PRODUCTION AND REVENUE

4.1 Fixed costs

The major fixed costs are building, electrical appliances, air supply system, water supply, plumbing, pipes and hoses, filter systems, tanks and their accessory, equipment for feed preparation, utilities, laboratory equipment, glassware, chemicals, furniture and vehicles. This component is about M$ 304 000 (Table 2).

4.2 Variable costs

The operation costs are energy, feed, general expenses, maintenance and repairs, insurance. This is about M$ 36 900 before the hatchery is on production. The cost is M$ 113 400, 139 400 and 160 000 in the first, the second, and the third years of operation (Table 3). The cost of production of juveniles per thousand is M$ 22.08, 17.43 and 16.00 in the first, the second and the third year, respectively.

4.3 Revenue

The return is taken from sales of the juveniles in the open market. The market value is about M$ 50 per thousand. The yield according to the production schedule is about 3 million, 8 million and 10 million in the first, second and third year, respectively (Table 4). Paying back period is between two to three years.

Table 1. Water quality for rearing the giant freshwater prawn (Macrobrachium rosenbergii) larvae

Table 2. Annual investment requirement (M$)

Table 3. Annual recovery (M$)

Table 4. Operating cost of hatchery (M$)

Table 5. Cash flow of the operation

Table 6. Comparative income statement (before taxes) (M$)

Fig. 1. Layout of the small-scale shrimp hatchery

Fig. 2. Larval rearing tank

WP/81/SPH/CP-9

DESIGN OF SMALL-SCALE SHRIMP/PRAWN HATCHERIES SUITABLE FOR DEVELOPING COUNTRIES IN SOUTHEAST ASIA: 2. MODEL DESIGN FOR A SHRIMP HATCHERY

by

Banchong Tiensongrusmee¹

1. INTRODUCTION

The production of penaeid shrimp from egg, larvae to postlarvae is now feasible. The technology is consistent, and expertise is available. To make shrimp hatchery a profitable enterprise, proper utilization of the existing technology is of prime importance. The successful operation of most hatchery is still an art rather than science. The presentation is an attempt to design a small-scale shrimp hatchery suitable for developing countries in Southeast Asia. Likewise, the design can be used as a model for projects in Malaysia.

2. SITE SELECTION

Selection of a suitable site is critically important for a new hatchery. But, despite this, many new ventures appear to have started on unsuitable sites. This is probably due to attempts of keeping initial expenditures to the minimum or sometimes the funding once obtained the start of the work is done by new and non-knowledgeable staff. The temptation is therefore present to ‘cut corners’ by only allowing a very shallow and short-term examination of site suitability in order to get the project moving. In many cases, a combination of luck, wisdom and subsequent design modification does result in commercial success. Often, however, failure of the project is later blamed on some unsuitable water quality, climatic conditions or disease factor.

The principal criteria for selection of suitable site for the hatchery are the following:

2.1 Seawater

The seawater in the area should be clean and relatively, free from silt. To avoid abrupt lowering of salinities in the rainy season, the site should not be located near river mouths. The water should have a salinity range of 28 to 32 ppt. It should not be affected by inland discharges containing agricultural runoff or industrial wastes. Turbidity should be as low as possible (Tabl 1). Adequate seawater should be available when needed.

2.2 Source of spawners

It is more desirable for the hatchery site to be near the source of spawners for a constant supply. At present, for penaeid shrimp the spawner can be obtained directly from shrimp ponds which is cheaper and more constant supply than spawners from the sea.

2.3 Road accessibility

The hatchery should be accessible by road for convenience in transporting supplies and other necessities for the hatchery operations. It is also convenient for the distribution of postlarvae to the farms.

2.4 Availability of electric power

Electricity is essential for hatchery operations. The site should be provided with a reliable power source.

2.5 Freshwater

It is not only essential for miscellaneous activities but also for the personal daily needs of staffs and when salinity of water is too high freshwater is also needed to bring down to requires salinity.

3. DESIGN CRITERIA AND SPECIFICATIONS

The hatchery is planned to have a production of 8–10 million penaeid larvae per year. The postlarvae are to be grown to 25 days (PL 25) with small tank, indoor culture technique. The maturation is done in indoor tanks.

¹ Senior Aquaculturist Team Leader Institutional Support for MAJUIKAN Aquaculture Development Project (FAO/UNDP/MAL/79/018) Kuala Lumpur, Malaysia

3.1 Size of hatchery

The size of about 0.5 ha is sufficient as site for maturation tanks, holding tanks, spawning tanks, hatching tanks, larval rearing tanks, algal rearing tanks, algal stock culture room and offices. The layout out of the hatchery is given in Fig. 1.

3.2 Water supply

3.2.1 Seawater

The seawater has to have a salinity range of 28 to 32 ppt. The water intake may either be from an inshore well or right from the sea. For the latter case, extreme care must be taken to be sure that the water will be free from fish, jellyfish as well as silt and mud during heavy runoff. This is done by employing a sand filter. The pipes are made of PVC and should be fully exposed for easier maintenance.

For ground water, it should not contain high levels of minerals, e.g. sulphur, iron, etc. It is essential that the seawater is consistently of the same good quality or it is necessary to have stable chemical parameters.

The hatchery will need a water pump (stainless steel type) with a capacity of 50 m³/min of seawater. Two submersible pumps with a capacity of 5 hp are needed.

3.2.2 Freshwater

The freshwater has to be clean preferrably of drinking water quality and not too hard. The pH should be 7 to 7.5. A pump with a capacity of 25 m³/min of freshwater is needed.

3.3 Air supply system

A source of air for aeration system can be either a low pressure and high volume given by a Roots air blower or cylindrical air pump, or a high pressure and low volume type given by a compressor. However, the former is preferred, because of its safer use, less complicated construction, and provides oil-free air. For the small-scale hatchery, the ordinary cylindrical air blowers may suffice, since the oil introduced into the system has no significant impact on larval survival, and its cost is only a fraction of what a Roots blower costs. The life span is also much longer. For the culture tanks where the maximum depth is less than two meters, a pressure of about 0.2–0.3 kg cm² is enough.

The size of the aeration system depends on the extent of the hatchery operation. For a 1-m deep tank, a 3.6 liter/min/m² of air is enough to ensure aeration for the oxidation of the high organic load in the rearing tank. The aeration is most crucial when at the zoea stage. To measure air volume for each outlet of the aeration system, this can be done by immersing a pail with volume markings into the water tank, turn it upside down and introduce air into it for a known period of time. The volume of air can be estimated from the markings in the submerged pail.

Carborundum grinding stones 9 cm long, 3 cm in diameter, hollow inside with an inside-well thickness of 0.5 cm are suitable. The airstone is used with 9 mm (inside diameter) plastic tube and a heavy sinker tied at the neck of the airstone. This type of airstone may be used at a rate of one airstone per 5 m² of area. PVC pipes are preferred for air distribution lines.

Stoppage of aeration is fatal to the larvae, and sudden power failures can be disastrous. Therefore, a battery-powered warning system must be installed to notify the culturist of any stoppage of the aeration system. For the compressor type, a warning system that is pressure-oriented to the air tank is required. For the blower type, a relay-type of warning system is needed.

3.4 Electricity

It is essential to have electricity continuously because the air blower is driven by an electric motor. Water pumps and housing also need electricity. A generator (400 V, 50 HZ, 1 500 rpm) with an output of 50 KVA and a 80 hp diesel motor with an output of 125 KVA are required.

3.5 Broodstock holding tank

Spawners can be obtained from the sea or from shrimp ponds. It has been observed that only spawners of P. monodon about 70 g size can be used successively in induced maturation of gonads through eyestalk ablation. The undersized spawners can be kept in the holding tanks. One circular broodstock holding tank with 3.5 diameter and 1.50 m height (15 ton) is required. The stocking rate is 5 animals/m² (Fig. 2).

3.6 Maturation tanks

After ablating an eyestalk (one eye) the female shrimp will be released in maturation tanks with unablated male. Shrimps were kept in the maturation tank for two-three weeks for maturation of the gonad after the eyestalk was ablated. After the gonads have developed to stage III and stage IV, the shrimps will be transferred to the spawning tanks. After spawning the shrimps will be returned to the maturation tanks again to remature the gonad for subsequent spawnings.

The maturation tanks can be any shape — circular, rectangular, or oval. Circular tanks have several advantages. Normally water velocities are higher than in rectangular tanks, leading to better conditioned spawners. Circular tanks are good for self-cleaning and can use lower flow of water. The disadvantage of circular tanks is that they consume more space.

Four circular maturation tank of the same size and of the same design as the broodstock holding tank will be required. Seawater is brought in through a vertical pipe. It is distributed through the concentric pipes and flows upwards. Water is drained through a double cylinder stand pipes located at the center of the tank. Three to five airstones are provided in the event pump breakdown or power failure occurs. A 24-hour flow through system allows a daily exchange rate of 25 percent of the total water volume in the tanks.

3.7 Spawning tank

Shrimp should be spawned in a separate tank where the mass of scum that the spawner extrudes with the eggs can be removed. Only good eggs are placed in the hatching tank. Two conical tanks diameter of 0.75 m and height of 1.50 m (Fig. 3) are required. The tank capacity is one ton. Two-three spawners can be spawned in each tank per run.

To remove the eggs, turn off the aeration. The eggs will settle down at the bottom. Slowly drain the water out through the outlet. The eggs will be collected at a collecting sump.

3.8 Hatching tank

The hatching tank should have a flat bottom surface so that the eggs can spread out. Two circular tanks with diameter of 1.50 m and height of 0.85 m (1.50 ton) is required (Fig. 4).

The water used in spawning tank should be filtered through filter with a mesh opening of 50 microns. Cover the tank with bamboo screen except for a small portion. Healthy nauplii will swim to the lighted area of uncovered portion of the tank. These nauplii are then collected by siphoning. Those that are too weak to swim to the light are discarded.

3.9 Larval rearing tanks

A 2-ton larval rearing tank is made of concrete with conical bottom (Fig. 5). It is 1.50 m in diameter. About 20 tanks are required. The initial stocking rate from nauplii is 250–300 pcs/1. The stocking density at post-larval stage should be 50–100 pcs/1.

3.10 Phytoplankton tank

About 20 circular tanks are required for phyto-plankton culture. The tank is flat bottom, 1 ton capacity with 1.50 m diameter, and 0.60 m height. The tanks are provided with aeration for efficient circulation and for keeping the organisms in suspension.

3.11 Water exchange filter

To prevent the loss of larvae during water exchange, a filter box with dimensions of 50 × 50 × 100 cm is used. The frame is constructed of hardwood treated with a polyester resin or use stainless steel. Two layers of screening material are attached to the frame. The inside screen should have approximately 3.0 to 4.0 mm mesh openings to reinforce and support the outside screen. For the late mysis and postlarval stages, the outside screen of plankton net material should have about 350 micron openings. For harvesting large postlarvae (i.e. PL 25), the mesh opening of the outside screen should be about 1 mm diameter to permit fast drainage without much clogging.

4. PRODUCTION REQUIREMENTS

4.1 Spawner

Assuming that one spawner produces 300 000 eggs of which about 200 000 will hatch to nauplii. The survival rate from nauplii to postlarvae is 40 percent. One spawner produce 80 000 postlarvae (PL 25). One batch of spawning requires about 35 days operation so that about 10 runs may be possible per year. One run requires 10 spawners. A hundred spawners are required. For continuous supply of spawners, two hundred females and three hundred males of broodstock will be needed per year.

4.2 Water quality

Water quality in rearing tanks has to be monitored and should satisfy the conditions given in Table 1. Virtually none of the major physical factors can be considered isolated from the others, e.g. temperature has influence on the tolerance of salinity, saturation of O₂ is a function of temperature. The toxicity of ammonia is a function of dissolved oxygen, temperature and pH. If the pH increases, the amount of unionized ammonia (NH₃) which is toxic to the larvae increases. The NH₃ and NH⁺₄ ratio is pH dependent. Even though ionized ammonia (NH⁺₄) is not toxic, because it is unable to pass the gill membrane of the larvae, measuring its concentration along with pH, DO, and temperature gives a clue on the toxicity of NH₃. Possibly the safe ammonia concentration can be taken to be 1.5 ppm NH⁺₄, and 0.1 ppm NH₃.

4.3 Feed

The larva is not able to seek food. Therefore, the optimum density of the food in the medium can ensure that the larva gets the food it needs.

4.3.1 Nauplii (N)

Feeding is not required for this stage.

4.3.2 Zoea (Z)

Phytoplankton. e.g. Skeletonema costatum, Chaetoceros spp, Tetraselmis spp, etc. are fed 4 to 5 times a day in order to keep a density of 20 000 to 60 000 cells/ ml, depending on the algae used, e.g. optimal for Skeletonema is 50 000 cells/ml. A Z3, rotifer at a density of 100 animals/ml are kept for additional food in the rearing tanks.

4.3.3 Mysis (M)

The nauplii of Artemia salina (brine shrimp) are fed to mysis. With brine shrimp cysts which have a 80 percent survival. 70 g/m³ of cysts are used on the first day. 100 g m³ on the second day and 170 g/m³ on the third day.

4.3.4 Postlarvae (PL)

During the first 10 days (PL 10) the postlarva is very sensitive to its environment. At PL 1-PL 6, the post-larva is fed 180 g/m³/day, and at PL 6 the postlarva is fed the nauplii Artemia about 80 g/m²/day.

This diet is supplemented from PL 7 with minced mussel flesh, fish flesh, etc. at a rate of 100 percent the first day, down to 10 percent of the body weight a week later. This depends on the amount being taken up. Once the larva is acclimatized (usually at PL 15) to lower salinity (12–14 ppt) 5–10 percent wet feed is sufficient. The animals should not be fed the day before they are moved to the nursery pond (usually after PL 10-PL 25).

5. COSTS AND RETURNS OF PRODUCTION

5.1 Fixed cost

The major fixed costs are building, electrical facilities, air supply system, water supply, piping filter systems, tanks and their accessories, equipment for feed preparation, utilities, laboratory equipment, glassware, chemicals, furniture and vehicles. This component could cost about M$ 534 950 (Table 2). The depreciation of the capital and its annual recovery are expressed in Table 3.

5.2 Variable cost

This component includes salaries of staff, energy, feed, general expenses, maintenance and repairs, insurance. The running cost before the hatchery is on production is about M$ 40 500. The annual operating cost up to the third year of operation is M$ 123 400, 190 000 and 221 800, respectively (Table 4). The cost of production of the postlarvae is about M$ 23-24 per 1 000 PL 25.

5.3 Revenue

The return is taken from the sales of the 25 day old postlarvae PL 25 in the open market. The market value is about M$ 50 per thousand. The expected yield according to the production schedule is about 5 million, 8 million and 10 million in the first, second and third year, respectively (Table 5). The anticipated incomes of the hatchery are M$ 76 000, 143 272, 208 310 in the first, second and third year, respectively (Table 6). Paying back period is between 3 to 4 years.

Table 1.
Suitable ranges of water quality for rearing the penaeid shrimp larvae

Table 2.
Annual investment requirement (M$)

Table 3.
Annual recovery (M$)

Table 4.
Operating cost of the hatchery (M$)

Table 5.
Cash flow of the operation (M$)

Table 6.
Income statement (before taxes) (M$)