Harmonization of Hatchery Production

CONTENT

1. INTRODUCTION

1. CURRENT STATUS

1. SITE SELECTION
2. Water Supply
3. Near the Aquaculture Site and the Market Place
4. Transportation
5. Electricity and Communication
6. Natural Disasters
7. Security

1. HATCHERY DESIGN
2. Size of Hatchery
3. Water Supply
4. Aeration System

1. SPAWNERS
2. Source and Abundance
3. Maturation Techniques
4. Feed and Feeding
5. Health Maintenance of Spawners

1. HATCHERY TECHNIQUES
2. Japanese Technique
3. Galveston Technique
4. Taiwanese Technique
5. Modification of the Technique by Each

ASEAN Country

1. FEED AND FEEDING
2. Feed
3. Feeding

1. WATER QUALITY MANAGEMENT

1. HEALTH MANAGEMENT

1. HARVESTING AND HANDING
2. Harvesting
3. Sampling Method

10.3 Packing

10.4 Handling

1. BIBIOLIGRAPHY

ILLUSTRATION AND TABLE

Figure 1:The Laboratory and the Outdoor Culture of Skeletonema sp.

Table 1: OptimumRanges 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:

3.1Water 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.

3.2Near 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.

3.3Transportation

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.

3.4Electricity 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.

3.5Natural 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.

3.6Security

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.

4.1Size 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:

4.1.1Small-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.

4.1.2Medium-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.

4.2Water 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.

4.3Aeration 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

5.1Source 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.

5.2Maturation 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.

5.3Feed 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.

5.4Health 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. Treflan0.01 ppm baths for 24 hours

6.HATCHERY TECHNIQUES

6.1Japanese 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.

The spawners are kept in the holding tanks before being placed into the hatching tanks. The volume of water in hatching tanks varies from species to species. The normal practice for P. japonicus is one spawner/2 m3, p. monodon is one spawner/5 m3, and p. indicus and p. merguiensis is one spawner/ m3. An initial water level of 100 cm is generally maintained. Spawning usually occurs at night that they were transferred from holding to the hatching tanks. After spawning the brooders are then removed in the early morning of the following day. If there is a few number of eggs or nauplii, the spawner may be left in the tank for another night. Soon after hatching, 3 ppm KNO3 and 0.3 ppm Na2HPO4 are applied as fertilizer. The amount of fertilizer applied thereafter depends on the density of plankton. During this stage, about 10 – 20 cm of fresh clean water is added daily depending upon the density of plankton. If the density of plankton is low, soybean cake, soybean curd, egg yolk, or fertilized eggs of oyster are given as supplementary food. Shrimp larvae begin to feed on the plankton when they reach the protozoa stage. During the mysis stage, they are fed with rotifer (Brachionus plicatilis) or brine shrimp (Artimia salina) nauplii. Once the post larvae reach PL6, they are fed with minced mussel, clam meat or formulated larvae feed with corresponding decrease in ration quantity of brine shrimp nauplii until they reach P9. Beyond this stage, the larvae are feed solely with minced mussel, clam meat or artificial diets 3-4 times a day. To ensure sufficient amount of algae in the rearing tank, pure cultures of diatom are used before the application of fertilizer. The advantages and disadvantages of these systems are :

Advantages :

1. The larvae can be raised up to PL 22 in the same tank;
2. Nursery tank is not necessary;
3. Less labour required for operation; and
4. Low cost of maintenance.

Disadvantages

1. High cost of initial investment;
2. Difficult to control disease; and
3. Large number of spawner is used in one operation.

6.2Galveston Technique

This technique was developed in 1960 by the Nation Marine Fisheries Service in Galveston, Texas, USA. It utilizes separate algae and diatom culture to control the feeding of shrimp larvae. Due to inconsistent supply of spawners, the hatchery is much smaller in size than in the Japanese technique. Spawning tanks and larva rearing tanks are separated. Both types of tanks are made from plastic or fiberglass. The capacity of larvae rearing tanks range from 1,000 – 2,000 litre and the spawner tanks from 100 to 250 litre. The stocking density is so high (200 – 300 nauplii/l) that the larvae can only be reared up to PL1 – PL5. Earthen ponds or concrete tanks are necessary for further rearing of juvenile before stocking in grow-out pond. In the larvae rearing tanks, alga cell are added daily during the protozoea stage and newly hatched artemia are given during the mysis and early post larval stage. The advantages and disadvantages of these systems are as follows :

Advantages :

1. Low initial investment;
2. Small number of spawners is required;
3. Nauplius (N) to post larvae (PL), could be reared in high density; and
4. Easy to control disease

Disadvantages :

1. It is difficult to raise larvae up to PL 22 is same density;
2. Nursery ponds are required; and
3. In the case of mass production higher manpower is needed.

6.3Taiwanese Technique

The rearing tanks range from 20 – 50 m3, either indoor or outdoor is used in this technique. The tanks are usually covered with canvas and equipped with heaters to control temperature. Shrimps larvae are fed with Skeletonema sp. or microencapsulated feed instead of Chaetoceros. At this stage antimicrobial is applied to control the disease.

Spawners are placed in the spawning tanks with low level of aeration. They will spawn during the night. After spawning, the water is stirred by using the paddle for 15 – 20 minutes/time until the eggs are hatched out. Then the eggs are sampled in order to estimate the numbers of nauplii. The nauplii are collected after stopping the water circulation and then lighting is applied to the hatching tank. The nauplii will swim up to the water surface toward the light. After that nauplii, are collected and transferred to the rearing tanks. Water temperature inside nursery tanks is controlled at 32 – 34 0C by covering with black canvas. Nauplii are fed daily with alga cells (Skeletonema sp.) and microencapsulated feed during the mysis stage. Newly hatched artemia and microencapsulated feed is given during the post larval stage.