HARMONIZATION OF
HATCHERY PRODUCTION OF Penaeus monodon
IN ASEAN COUNTRIES
F i s h e r i e s P u b l i c a t i o n S e r i e s No.3
CONTENT
1. INTRODUCTION
2. CURRENT STATUS
3. SITE SELECTION
3.1 Water Supply
3.2 Near the Aquaculture Site and the Market Place
3.3 Transportation
3.4 Electricity and Communication
3.5 Natural Disasters
3.6 Security
4. HATCHERY DESIGN
4.1 Size of Hatchery
4.2 Water Supply
4.3 Aeration System
5. SPAWNERS
5.1 Source and Abundance
5.2 Maturation Techniques
5.3 Feed and Feeding
5.4 Health Maintenance of Spawners
6. HATCHERY TECHNIQUES
6.1 Japanese Technique
6.2 Galveston Technique
6.3 Taiwanese Technique
6.4 Modification of the Technique by Each
ASEAN Country
7. FEED AND FEEDING
7.1 Feed
7.2 Feeding
8. WATER QUALITY MANAGEMENT
9. HEALTH MANAGEMENT
10. HARVESTING AND HANDING
10.1 Harvesting
10.2 Sampling Method
10.3 Packing
10.4 Handling
11. BIBIOLIGRAPHY
ILLUSTRATION AND TABLE
Figure 1: The Laboratory and the Outdoor Culture of Skeletonema sp.
Table 1: Optimum Ranges of Water Quality for Rearing Penaeid Shrimp Larvae
HARMONIZATION OF HATCHERY PRODUCTION
OF Penaeus monodon IN ASEAN COUNTRIES
1. INTRODUCTION
In 1934 Dr. Fujinaga, the world’s acknowledged father of shrimp culture, successfully spawned and partially reared the larvae of Penaeus japonicus in Japan (Hudinaga, 1942). In 1963, Mr. Cook of Galveston Laboratory in Texas, United State of America in collaboration with Dr. Fujinaga, successfully spawned and reared the larvae of two American species, P. Setiferus and P. Aztecus (Cook and Murphy, 1966). The spawning technique was later adopted and used by many hatcheries in Asia which include Taiwan, the Philippines, Thailand and Malaysia. Species of shrimp that have been produced in those countries are local species such as P. monodon, P. merguiensis, P. indicus and P. orientails. The technique now is modified for proper larval production practice by combining the advantages of both Japanese technique and Galvaston technique such as done in Taiwan, the Philippines, Thailand and Malaysia.
2. CURRENT STATUS
It was reported by ASEAN Shrimp News (Issue, No. 20, 1994) that there were approximately 3,700 shrimp hatcheries in ASEAN countries in 1994. At least 96,000 shrimp spawners are required each year to supply the hatcheries to produce over 54 billion of shrimp larvae. It is inevitable that the demand of shrimp fry for shrimp culture industry would be increased sharply in the near future particularly in India, Vietnam and Bangladesh where shrimp farming is rapidly expanding. To supply adequate amount of shrimp fry for shrimp farming industries in the region, good shrimp hatchery practice manual should be published.
The purpose of this manual is to compile the information on the appropriate shrimp hatchery techniques from different ASEAN Member Countries to be used as a guideline for shrimp hatchery practice.
3. SITE SELECTION
The criteria for site selection for shrimp hatchery are as follow:
3.1 Water supply
Seawater supply should be clean, clear and relative free from silt and pollution. The quality and quantity of seawater must be suitable for hatcheries work. The salinity should be around 28-33 ppt (for dilution process, up to 120 ppt is usable).
Fresh water is necessary to control the salinity of plankton culture and nursery or acclimatization of fry during transportation to farm pond area. Fresh water is also used for cleaning equipment.
The hatchery should be located away from water pollution sources i.e. industrial areas and urban communities which release industrial and domestic waste to the water source.
3.2 Near the Aquaculture Site and the Market Place
The hatchery should preferably be located near the farm pond area to minimize transport duration and stress to the seed and to ease marketing of product. The hatchery should be located near a place where essential materials are available for hatchery, such as feed for broodstock and fry, tools, equipment and other facilities. Source of spawner for constant supply is also taken into consideration in hatchery site selection.
3.3 Transportation
The hatchery should be accessible (by road, plane or boat) for convenience in transportation of spawner, nauplius and postlarvae to and from the hatchery. It should also be convenient for distribution of spawners or nauplius to the hatchery and for distribution of post larvae to the farm.
3.4 Electricity and Communication
The hatchery should be provided with a reliable electric power supply for all electric equipments, i.e. water pump, air blower, laboratory equipment, hatchery light etc. Stand-by gasoline engine generator must be available in case of electric power failure.
Telephone communications are also essential for the hatchery in order to facilitate consultations with experts in emergency situations and to make urgent orders of hatchery supplies, such as spawner, nauplius, feed, chemicals and drug.
3.5 Natural Disasters
The location of the hatchery should be carefully selected to avoid natural disasters such as storm, high waves and strong winds to prevent damages and destruction of the facilities and equipments.
3.6 Security
For security, the hatchery should be placed far from sensitive areas where poaching can be prevented. The electric circuits and electric equipments should be supplied with a safety cut.
4. HATCHERY DESIGN
The design of the hatchery should be simple, economic, neat, compact and easy to be operated with maximum efficiency. The materials used should be locally available, cheap and long lasting. It can be made from a wide range of materials: reinforce concrete, ferro concrete, fiberglass and wood with plastic lining for example.
There is no specific pattern for layout of the hatchery. The arrangement of tanks and working spaces should be based on working performance to save time and labour during the operation. The hatchery should be covered to protect against rain and sunlight and also to keep certain level of temperature.
4.1 Size of Hatchery
There is no limitation in size of hatchery, as long as there is space for broodstock or maturation tanks, spawning tanks, larvae rearing tanks, nursery tanks and algae or food organisms rearing tanks. Normally, there are three sizes:
4.1.1 Small-scale Hatchery
This type usually has a total rearing capacity of 100 – 200 cubic meters, and each tank has a capacity of 10 – 15 cubic meters, 1-1.8 meters in depth and in any shape (circular, rectangular or square). The construction materials are concrete, ferocement, fiberglass or others. In most of the hatcheries, its water temperature is controlled by covering the tanks with black canvas or tile. The size of small-scale hatcheries is meant to suit the farmers and are usually located in the coastal areas. Some hatcheries are modified from Macrobrachium hatcheries. Most of them are located far from the coastal area. They generally use hyper saline water from salt farms, and subsequently dilute to the desired salinity.
4.1.2 Medium-scale Hatchery
A medium-scale hatchery has the total tank capacity of 201 – 500 cubic meters. It was developed by combining the best features of small-scale and large-scale hatcheries. The rearing tanks usually have a capacity of 10 – 25 cubic meters, 1.5 – 2.0 meters depth and in any shape. The rearing tanks are usually placed outdoor and covered with black canvas and equipped with heater for temperature control. Water temperature can also be controlled by covering the tanks with black canvas inside a plastic covered house to save electricity.
4.2 Water Supply
The sea water supply system consist of a water intake pipeline, water pump and reservoir. A single pipeline is required for the seawater intake system. For small – scale hatchery with 10 to 15 tanks, a 2 hp. electric pump and a 10 to 15 ton reservoir should be adequate to supply sea water for the hatchery. For the medium-scale hatchery and the large-scale, stainless steel pump with a capacity of 50 m3/hr of seawater is required. Two submersible pumps with a capacity of 2 hp are also needed.
However, if clean sea water is not available, sea water should be pumped and supplied through a sand filter or through the bag filter, and chlorinated with 50 ppm hydrochloride overnight, and neutralized with sodium thiosulfate before using.
4.3 Aeration System
An air pump should be available all the time in the hatchery. The aeration system can be either low pressure with high volume given by a roots air blower, or a high pressure with low volume type given by a compressor. The farmer generally preferred less complicated equipment which oil-free air because it is save to use. For the small-scale hatchery, the ordinary cylindrical air blower is sufficient, since the oil introduce into the system has no significant impact on shrimp larvae. For the culture tanks where the maximum depth is less than two meters, an air pressure of about 0.2 – 0.3 kg/cm2 is enough. The capacity of the aeration system depends on the size of hatchery. For a 1-m deep tank, a 3.6 liter/min/m2 of air is enough to ensure oxidation of the high organic load in the rearing tank.
There are many techniques to aerate the tank. One technique is to connect an Eslon rubber air tube with an air stone. One air stone is adequate for 0.5 m2 of water area. Another technique also uses an Eslon tube. The tube is drilled to make several holes for air diffusion which is placed on the bottom of the tank. Air is injected into the water through these holes.
Aeration should be operated at all time during nursery period. Therefore, a battery-powered or gasoline generator must be installed to be an alternative power supply in case of power failure.
5. SPAWNERS
5.1 Source and Abundance
In Thailand, shrimp broodstock, gravid females for artificial seed production in hatcheries come from the wild. They are captured by trawler at the depth of more than 40 m, 100 – 150 km. offshore in the Andaman sea. The peak season to capture gravid female is normally from December to March and June to September. It is relatively poor to catch gravid female during the monsoon period. As shrimp fecundity and egg quality increase with body size, the good quality brooder therefore must be larger than 23 cm. with various stages of maturity eggs. The brooders are kept in the holding tanks on board with aeration system. Transportation of shrimp brooders to the hatchery is made shortly after the trawler arrived at the port. Normally, 4 – 10 brooders are packed in plastic bag with oxygen at a temperature of above 20 – 220C. Shrimps can survive in a good condition for 6 – 8 hrs after catching.
5.2 Maturation Techniques
Kungvankij (1982), Tiensongrusmee (1982), Primavera (1982) reported that three basic techniques, including eyestalk ablation, nutrition and manipulation of environment, are used separately or in combination to induce shrimp maturation. Gravid females with weight over 100 g are mostly used for eyestalk ablation. After eyestalk ablating the brooders are then released in the maturation tanks with unablated male. Generally, the sex ratio is maintained at 1 – 2 males to 1 female, and stocking rate is 5 – 8 shrimp/m2. Shrimps are kept in these tanks until the gonad is conditioned, usually about 3 – 7 days after the eyestalk ablation. The frequency of broodstock examination in the tanks varies from daily to every other day. After the gonad has developed to stage II and stage IV, the shrimp will be transferred to the spawning tank which is equipped with an aerator. After spawning, the shrimp will be returned to the maturation tank again to remature the gonad for subsequent spawning.
The maturation tank can be of any shape (circular, rectangular or square) and any size varying from 5 – 50 tons in capacity, 1 – 2 meter in depth. Construction materials including concrete, ferrocement, fiber adjusted in suitable conditions and maintenance of water quality by regular siphoning out of debris, etc. Water may be flown through, recirculated or with regular (daily, twice a week, etc.) renewal. Normally, the maturation tanks are covered with black canvas or kept inside the house to reduce stress and to easily check gonad stages by using flashlight.
5.3 Feed and Feeding
Molluscs meat, including mussel, clam, cockle, crab and squid meat, are the most common food for the broodstock. Other food items are those of fresh or frozen with high protein contents (40 – 60%) marine worms, mysid, shrimp and dried pellets. These foods may be given individually or in combination with daily feeding rate of approximately 10 – 30% or 3 – 5% of shrimps weight for wet feed and dried feed (pellet), respectively. Feed should be given up to four times a day and the daily ration is divided accordingly.
5.4 Health Maintenance of Spawners
Prevention of diseases through proper nutrition and maintenance of good water quality is more important than control. However, bacterial diseases such as zoothamnium and fungal diseases can be controlled through application of antibiotic or chemicals such as:
Bacterial diseases
a. Oxytetracycline 1.0 – 5.0 ppm baths for 3 – 5 days
b. Furazolidone 1.0 – 5.0 ppm baths for 3 – 5 days
10 – 20 ppm baths for 24 hours
c. Chloramphenicol 1.0 – 3.0 ppm baths for 3 – 5 days
Zoothamnium diseases
a. Fomalin 40% 25 – 50 ppm baths for 24 hours
Fungal diseases
a. Malachite green 0.01 ppm baths for 24 hours
0.05 ppm baths for 10 minutes
b. Treflan 0.01 ppm baths for 24 hours
6. HATCHERY TECHNIQUES
6.1 Japanese Technique
In Southeast Asia, Japanese technique which was established by Kittaka in 1994 is widely used in most hatcheries. It is based on the idea of utilizing natural occurring diatoms in the rearing pond as food for the larvae. To ensure adequate growth of the diatoms, water in larvae rearing tanks is enriched daily with fertilizer. The rearing tanks are either of rectangular or square shape with a capacity of 40 – 2,000 cubic meters, 1.5 – 2.0 meter depth and is normally located outdoors or indoors. For indoor tanks, partially transparent roofing is provided to allow sunlight penetration. In this system, spawning, larvae rearing and nursery operation are operated in the same tank. Technical grade fertilizers are applied directly to the tank after removal of spawners and hatching of eggs.