4. Tiger Prawn Hatchery Operations.pdf

CENTRAL LUZON STATE UNIVERSITY College of Fisheries Science city of Muñoz, 3120 Nueva Ecija 2024 Fisherie...

CENTRAL LUZON STATE UNIVERSITY College of Fisheries Science city of Muñoz, 3120 Nueva Ecija 2024 Fisheries Professional Licensure Examination (FPLE) Review Class TIGER PRAWN HATCHERY OPERATIONS Resource CHRISTIAN N. GARCIA, MSc, CSPE, RFT Person Aquaculturist II, BFAR Region 1  Basic Biology Tiger Prawn Penaeus monodon ENVIRONMENT METRICS benthic; brackish; depth lengthmax - 33.6 cmmale range 0-150 m; tropical lengthmax - 35.0 cmfemale 17-38°C lengthrange - 4-4.22 cm weightmax - 250 g HABITAT FEEDING HABIT juveniles are found in estuarine less of a scavenger; mainly a REPRODUCTIVE BIOLOGY predator of slow moving benthic environments, mangrove inlets, and gonochoric; attains full maturity macro-invertebrates like small crabs mangrove vegetate area; enters and spawning at 10 months in and mollusks; capable of capturing shallow brackish water or kept in the wild; two pronounced more mobile forms like small ponds; found in seagrass and among spawning season: December- penaeids and fishes shells; recorded in the water column March & June-September Basic Biology Tiger Prawn Penaeus monodon Life History Phases of the Giant Tiger Prawn Biosecurity in Prawn Hatchery 1. Standard Operating Procedures ▪ Shrimps are vulnerable to diseases; hence, biosecurity measures should be strictly implemented. ▪ Following strict biosecurity protocols prevents the exposure of healthy stocks to diseases and avoids contamination. ▪ The following are standard operating procedures (SOP) that a shrimp hatchery must follow: 1. It is recommended to have a spawner/broodstock facility. It will be a separate area from the shrimp hatchery that will be used to quarantine spawners while they are being processed and sampled for pathogen detection. 2. Prior to the arrival of the spawners or broodstocks, the whole area will be prepared, cleaned and disinfected, including the facilities and equipment. 200 ppm chlorine solution will be prepared and splashed into the tanks and reservoir. It will then be left in the tanks for at least one day before being washed with detergent and rinsed with freshwater. Biosecurity in Prawn Hatchery 3. Other materials such as air hoses, air-stones, pails, basins, dippers, filter bags, filter nets, and other paraphernalia will be soaked in chlorine solution prior to the start of the operation. 4. After disinfection, the spawning tanks will be prepared by installing the aeration lines and covering them individually with black nets and black sacks. It is recommended that each tank must be provided with all necessary materials, such as filter bags, scoop nets, pails, and dippers, separately from the other tanks to prevent any cross- contamination. 5. Signages, foot baths, and hand sanitizers will be provided at the main entrance of the hatchery. Disinfectants such as alcohols, bleach, and chlorine must be available inside the facility. Slippers or rubber boots will be provided and will be used solely inside the facility 6. Only authorized staff or hatchery personnel will be allowed to enter the facility and handle the stocks. The use of gloves is highly recommended to avoid contamination. 7. A “one-way in and out” scheme will be practiced for entrance and exit. Natural Food Production 1. Indoor Culture of Diatoms (Skeletonema sp.) ▪ For indoor culture, UV-sterilized seawater will be used to culture the diatoms. ▪ The fertilizer that will be used for diatoms is: F-medium (composed of EDTA, trace metals, vitamin stock, disodium phosphate, ferric chloride, and disodium silicate) TungKang Marine Research Laboratory medium (TMRL) (composed of sodium nitrate, disodium phosphate, ferric chloride and disodium silicate) 1. Examine the starter under the compound microscope to check if the cells are suitable for culture. 2. Add appropriate volume of UV-sterilized seawater in clean glass containers 3. Add fertilizer at 1 ml per liter to the container and to be followed with the addition of the starter. 4. Provide aeration and illumination until the culture is ready to be fed or scaled up to larger containers. Natural Food Production 2. Outdoor Culture of Diatoms (Skeletonema sp.) 1. Prepare the concrete algal tanks for the outdoor culture of Skeletonema sp. 2. Place a ton of UV-sterilized seawater and supply with aeration. 3. Two types of fertilizers will be used: urea (46-0-0) and ammonium phosphate (16-20-0). Completely dissolve urea (75 g) and ammonium phosphate (20 g) in a pail of freshwater prior to application. 4. Filter the fertilizer solution using a 90 µm filter net, and add the diatom starters. 5. The diatoms will be expected to bloom for 3-4 days before they will be harvested. 3. Harvesting of Diatoms (Skeletonema sp.) 1. To harvest diatoms, attach a double-lined harvesting bag at the end of the drain pipe of the algal tank. 2. Slowly remove the stand pipe to allow the diatoms to flow, thereby concentrating in the harvesting bag. 3. The concentrated diatoms will be placed in pails and will then be divided for feeding. The recommended feeding density for algae is 20,000-50,000 cells/ml. Natural Food Production 4. Culture of Brine Shrimp (Artemia) 1. Weigh the desired amount of Artemia cysts. 2. Hydrate the Artemia cysts in a pail supplied with aeration and UV-sterilized seawater for an hour. 3. Disinfect the cysts with 20 ppm sodium hypochlorite for 15 minutes. 4. Rinse the cysts with running UV-treated seawater until the smell of sodium hypochlorite disappears. 5. Incubate the cysts in a 250 L incubation tank filled with UV-sterilized seawater with aeration for 24 hours. 5. Harvesting of Brine Shrimp (Artemia) 1. Prior to harvest, remove the aeration and cover the top portion of the incubation tank for at least 30 minutes to separate the unhatched cysts from the nauplii. The unhatched cysts will float while the nauplii will accumulate at the lower portion of the tank. 2. Slowly open the outlet of incubation tank to avoid mixing of unhatched cysts and nauplii. 3. Collect the nauplii using a filter box and wash with running UV-sterilized seawater. The nauplii will then be concentrated in a pail and fed to the shrimps. Prawn Hatchery Design Spawner/Broodstock Facility Shrimp Hatchery Complex Prawn Hatchery Operations 1. Selection and Processing of Spawners 1.1 Acclimatization and Disinfection ▪ Penaeus monodon spawners will be delivered from the source to the spawner/broodstock facility. The spawners must be packed in transport/ broodstock bags with ample amount of seawater and aerated using battery-operated aerators. Processing of Spawners 1. Upon arrival, acclimatize the spawners by placing them in white basins with aeration. 2. Check the salinity of the transport water and seawater on site to determine the salinity difference between the two. The salinity inside the basin should be slowly adjusted to equalize with the salinity of the water in the transport bag. 3. When the salinities of both waters have already equalized, the spawners will then be allowed to acclimate for two hours. 4. After two hours, disinfect the spawners using 50 ppm povidone-iodine (added to the water in the basin). Prawn Hatchery Operations 1.2 Checking of Gonadal Maturity and Stocking 1. After disinfection, individually place the spawners in the spawning tanks. 2. While they are being transferred to the spawning tanks, check their gonadal maturation (by lighting). 3. Individual scoop nets will be used to transfer each spawner to avoid contamination. 4. Each tank will be covered with black nets and black sacks. 5. The spawners will be allowed to stay overnight for spawning. Stages of gonadal development and maturity of P. monodon Prawn Hatchery Operations 1.3 Eyestalk Ablation ▪ P. monodon females, unlike males, do not attain maturity in captivity unless they undergo ablation or destruction of one eyestalk. ▪ Shrimp are ablated only when hard-shelled, never when newly molted (soft-shelled) or ready-to molt (with whitish spots on shell). ▪ Only the healthy animals with clean shells, intact legs and tails, and uninfected gills must be ablated. Reproductive Organs of P. monodon Prawn Hatchery Operations Process of Ablation 1. The shrimp will be gently but firmly held with one hand. The sex will be checked, and only females will be ablated. Shrimps with broken or diseased external sex organs (petasma or thelycum) will not be used. 2. The ovarian maturation stage will be checked by external examination. Only immature (Stage I) and early maturing (Stage II) females will be ablated. Late maturing (Stage III) ripe (Stage IV) females are ready to spawn. 3. The thelycum will be closely examined for presence (bulging, with a whitish vertical streak on each side) or absence (depressed, evenly colored with no whitish streak) of sperm sacs. Only females which appear to have sperm deposited in the thelycum will be ablated; the rest will be returned to the holding tank for mating with males. 4. Ablation will be performed on either the left or right eye. However, an already infected or otherwise damaged eye will be ablated to leave one unablated healthy eye. Prawn Hatchery Operations 5. Ablation will be performed through the following ways: Pinching - An incision is made on the eye with a sharp blade, the contents are squeezed out, and eyestalk is crushed 2-3 times to destroy the tissue. This is the preferred method because one person can do it alone. The eyestalk heals even without the use of antibiotics; the external (corneal) layer forms the scar tissue in a week’s time. Ligation - The eyestalk is tied with a piece of string at the base close to the carapace, to fall off in a few days. This process needs two persons - one to hold the prawn while another ties the eyestalk. Cautery - The eyestalk is ablated by squeezing with a pair of red-hot forceps or by using an electric cauterizer (nichrome wire, 5 volts). This requires a cauterizer which may not be easily available. Cutting - The eyestalk is cut off with a pair of sharp scissors about 3-5 mm from the base. This is inconvenient because it requires additional sealing by cautery; otherwise, loss of blood from the open (cut) eyestalk may lead to mortality. 6. Ablation will be performed quickly and with the shrimp underwater to minimize stress. Prawn Hatchery Operations ▪ After ablation, the shrimp will be immediately released. ▪ Mortality due to ablation stress should not be more than 10%. ▪ Ovarian maturation follows a few days or weeks after ablation, and spawning may occur as quickly as three days after ablation. ▪ If ablation is done during the inter-molt, maturation and spawning will immediately follow. ▪ When ablation is during the early premolt, the females will first molt before they start to mature. 1.4 Post-Spawning Sampling ▪ In the following morning, remove the spawners from the spawning tank and check if they have spawned. Those that were unable to spawn will be allowed to stay for another night. ▪ Place the spent spawners in a labelled resealable plastic bag and send to a fish health laboratory for PCR tests. Prawn Hatchery Operations 2. Egg Disinfection and Treatment 1. Remove the spent spawner from the spawning tank. 2. Clean the tank by removing the scum and dirt that were released with the eggs during spawning using a scoop net. 3. Harvest the eggs by siphoning the water from the spawning tank and allow to flow in the 90 µm harvesting box placed in a basin with aerated UV-sterilized seawater. 4. Three white basins will be prepared beforehand. One basin will be used for the first washing of the eggs. The second basin will be for the disinfectant, and the third basin will be for the second washing or rinsing of the eggs. 5. The disinfectant will be prepared by mixing 1 ml of povidone-iodine solution in 20 L of water in the basin. The water will then be aerated for homogenous mixing. 6. After the first washing (5 minutes), harvesting box with the eggs will be placed in the second basin supplied with UV-sterilized and aerated seawater with disinfectant for 1 minute. 7. The eggs will be placed again in the third basin for rinsing for another five minutes. 8. The washed eggs will then be stocked in another clean tank supplied with UV- sterilized and aerated seawater to facilitate hatching. Prawn Hatchery Operations 3. Harvesting and Stocking of Nauplii ▪ The following morning, the hatching tanks will be checked to monitor if the eggs have hatched into nauplii. ▪ The processing and stocking of nauplii will be based on the results of the PCR analyses made on the spent spawners. ▪ Pathogens are transferred from mother to offspring via vertical transmission. Hence, only the nauplii from the PCR-negative spawners will be stocked. 1. Gradually release the water from the hatching tank to the harvesting box which is placed in a basin with UV-sterilized seawater. 2. Scoop-out the nauplii slowly using a dipper, and place in a pail with aeration. 3. Estimate the nauplii in the pail to have an initial count before stocking. 4. The nauplii will then be transported from the Spawner/Broodstock Facility to the shrimp hatchery using clean and covered pails. The nauplii will be acclimated for 30 minutes before gradually releasing to the tanks. Prawn Hatchery Operations 4. Feeds and Feeding Scheme Prawn Hatchery Operations 5. Water Management ▪ The water will be changed when the larvae have totally metamorphosed to the PL stage. Water change will be done every other day and depends on the water quality and fry condition. ▪ Water change at PL 1 usually starts at 10% and gradually increases up to 50% until the shrimp fry is of harvestable age. 6. Water and Fry Quality Monitoring ▪ Daily monitoring and checking of larvae will be done to detect occurrence of any problem and diseases. ▪ Bacterial analyses will be done twice a week starting from PL 1, while PCR analyses and fry quality monitoring will be conducted at PL 5, 10, and 15. ▪ Shrimp larvae will also be sampled to determine the estimated count during different stages of shrimp. Prawn Hatchery Operations 7. Harvesting of Postlarvae 1. The harvesting net will be prepared inside the harvesting pit. 2. UV-treated seawater will be added inside the pit. 3. Before harvesting, the water level in the tanks will be reduced to about 1/4 of the total volume to lessen the pressure on the drain pipe during the release of water thereby minimizing stress on postlarvae. 4. After reducing the water level, the stand pipe will be partially removed and placed in a slanting position, and the remaining content of the tank will be allowed to flow in a controlled manner into the harvesting net inside the harvesting pit or box. 5. The PL will be collected and concentrated using a clean scoop net and will then be transferred into a basin supplied with UV-sterilized and aerated seawater. 6. The harvested fry will later be distributed in white basins for counting and packing. Prawn Hatchery Operations 8. Packing and Transport of Shrimp Fry 1. The harvested fry will be placed in basins with UV-sterilized seawater and supplied with aeration. They will be counted based on the desired packing density per bag during transport. 2. The estimated fry will be distributed to the other basins based on the counted fry density. 3. After estimating, the fry will be transferred from the basins into doubled polyethylene (PE) bags. The inner bag will contain 1/3 UV-sterilized seawater and 2/3 oxygen by volume, and the inner and outer bags will be separately tied with rubber bands. If the travel time exceeds 6 hours, water temperature will be lowered to 25 °C by placing wrapped ice on top of the inner plastic bags. Reference Material de la Peña, L. D., Baliao, D. D., Mamauag, R. E., Tambirao, J. G., Dosado, N. B., Tillo, A. D., Gatumbato, R. G., Failaman, N. O., Navarro, J. C., & Dayrit, R. (2023). Black tiger shrimp (Penaeus monodon) hatchery operations using enhanced biosecurity measures. Aquaculture Department, Southeast Asian Fisheries Development Center.  Thank you CHRISTIAN N. GARCIA, MSc, CSPE, RFT Aquaculturist II, BFAR RFO1