Annex 4 SEAFDEC DEPARTMENTAL PROGRAMS OF ACTIVITIES
3. PROGRESS OF ACTIVITIES IN THE YEAR 2007 1. Shrimps
a. Enabling aquatic animal health capacity through geographic information system (GIS):
Diseases of Crustaceans
A draft webpage has been constructed for fish and crustacean diseases, but refinement of structure is still on-going. Webpage design is being optimized to accommodate GIS maps as well as relevant information related to the target diseases such as description, photos of disease signs, and links to references. GIS mapping of target diseases is a regular activity and data have been grouped to show maps by species, disease, and period of occurrence.
b. Development of specific pathogen-free shrimp (P. monodon and P. vannamei) broodstock (under ASEAN-Government of Japan Trust Fund)
Information exchange on status of P. monodon captive broodstock development in Southeast Asian region and the possible impact of the introduction of P. vannamei in the region
P. monodon breeding program. Multiplication centers have been established in Thailand, Vietnam and India for SPF P. monodon fry produced in Hawaii. Shrimp Culture Research and Development Company Ltd in Thailand had produced F6 domesticated P. monodon. Thai Union Feed Mill formed joint venture with HH Aquaculture to produce SPF fast growing and TSV resistant shrimp nauplii and postlarvae. Indonesia has not gone into breeding program. In Malaysia, the performance of SPF P. monodon improved 50-80% in grow-out pond. In the Philippines, maturation in captivity was achieved even without ablation but spawning was attained only after ablation. Two batches of F1 have been produced.
P. vannamei and other exotic shrimps. Various countries in Southeast Asia have already gone into the breeding and culture of white shrimp as an alternative to P. monodon. In Indonesia, Penaeus vannamei stocks were imported legally in 2000, fry were grown in ponds and from these, broodstocks were selected for use of private hatcheries. In Thailand, legal importation of P. vannamei has been allowed since mid 2002 but on the condition that these are free of viruses.
In Brunei Darussalam, after the successful verification trials on breeding and culture of P.
stylirostris, farmers had started growing this species in their ponds in 2000. In Singapore, biosecure facility has been established by Shrimp Improvement System, USA in 2005.
Postlarave are grown to broodstock size and sold to operators in Malaysia, Indonesia and Myanmar. Vietnam has also joined the league of white shrimp producers.
In the Philippines, specific pathogen-free Penaues vannamei broodstocks imported legally imported from USA were bred and postlarvae were distributed to accredited shrimp farmers. In 2007, the ban that prohibits the entry of exotic shrimps and prawns in the country was lifted, thus shrimp growers are now openly growing this species. Soaring postlarvae demand has led to the selection of market size P. vannamei from ponds by enterprising private sectors and utilization of these as source of broodstock for local hatcheries. This could start the spread of exotic diseases if proper screening is not implemented. There are already reports of P. vannamei occurrence and catch in local waters due to mass release of stock by scared growers before the lifting of the ban and floods.
Genetic characterization of Penaeus monodon broodstock
Pleopod samples from P. monodon collected from Bohol, Roxas and Bacolod in November 2006 are being processed. Preliminary observation show genetic differences between stocks based on restriction morphs obtained after digestion with restriction enzymes: MspI and EcoRI.
Restriction morphs obtained from RFLP analysis using RsaI and HaeIII show monomorphic patterns in all three stocks.
Studies on improvement of maturation of pond-reared P. monodon broodstock
Two batches of pond-reared P. monodon have been grown to broodstock size. Batch 1 females were matched with batch 2 males and vice versa. Even without ablation, 4 females have matured, but spawning was achieved only after ablation. A total of 2 batches of F1 have been produced, but the fecundity (32,000) and hatching rate (15%) was low. The first batch of F1 has grown to 5-10 g while the other batch is still at the PL15 stage. The bigger juveniles from F1 batch 1 were stocked in another tank and will later be used as broodstock when the desired size has been attained.
Separation of males and females was done for the first batch to observe its effect on percent mating. Males and females that were previously separated then mixed had 50-60 % mating and those that were mixed from the start of culture had 67-100%.
Wild fry have been obtained from Antique and Palawan to augment the shrimp stocks currently held for broodstock.
c. Penaeus indicus/P. merguiensis broodstock development: 1. Refinement of broodstock management and larval rearing of P. inidcus/merguiensis
Two runs have been conducted to compare the SEAFDEC-developed probiotics with antibiotics and other commercial water treatments. The first run (treatments: oxytetracycline (Oxy), an antiviral commercial product (Vir), a sulfadiazine antibiotic (Tri) and the SEAFDEC-developed probiotic (SFDC)) showed that survival at PL1 and PL15 was similar for all treatments;
however, survival rates were very low. In the second run, 2 more treatments were included namely; a commercial probiotic (Pro) and a probiotic from France (Fr). At PL1, Oxy (27.9 ± 3.2) had significantly higher survival than all other treatments, but at PL15 Oxy (20.0 ± 1.7%) and SFDC (16 ± 1.8%) gave similar survival rates. During this run, luminescent bacteria were found in all stocks except in those treated with the SEAFDEC-developed probiotic.
Six batches of F2 have been produced and are now being reared to broodstock size. Additional batches of parental stock (Po) have produced 4 batches of F1.
d. Verification of Penaeus indicus grow-out diets in ponds using environment-friendly scheme
Due to lack of enough white shrimp P. indicus postlarvae, P. vannamei postlarvae were stocked in ponds. The use of SEAFDEC shrimp diet (29% crude protein) and a leading commercial P.
vannamei feed (52% crude protein) were some of the major changes done to undertake the study. Biosecurity measures such as installation of peripheral net fences to eliminate possible WSSV carrier crustaceans, successive chlorination of culture water, provision of foot bath and hand wash with disinfectants, and application of probiotic were employed. A total of 150 pcs
‘hatirin’ milkfish were stocked at the central sludge collector while a 1:1:1 ratio of milkfish : tilapia : siganids were partially stocked at the corner sludge. Similarly, the reservoir (pond 16) was stocked with milkfish, tilapia and siganids as biomanipulators.
e. Studies on the nutritional quality assessment of feeds and feedstuffs and their effects on growth, health conditions, immune response, aquaculture production, and environmental degradation of marine invertebrates commonly cultured in the Philippines: New aquaculture technology for various penaeid species
Newly approved study.
3.2. Mud Crabs
Domestication of mud crab Scylla serrata
Mud crab S. serrata from Cagayan, Camarines Norte, Northern Samar and Surigao were obtained for genetic diversity analysis and husbandry. Crabs were screened for White spot syndrome virus (WSSV), Infectious hypodermal and hematopoietic virus (IHHNV), Gill associated virus (GAV), Yellow head virus (YHV) and Taura syndrome virus (TSV). Crabs were selected and maintained in maturation tanks.
Results of screening showed that all crabs from Camarines Norte, Samar and Surigao were negative for the five viruses. Crabs from Cagayan were negative for the viruses except for 2 crabs (out of 5 crabs examined) which were found to be positive for IHHNV. To date, crabs from this first generation are in the megalopa and juvenile stages.
Refinement of broodstock management and seed production techniques
Broodstock. The reproductive performance of mud crab S. serrata broodstock maintained in outdoor (T1) and indoor (T2) maturation tanks with sand substrate was determined. The duration from spawning to hatching of ablated crabs ranged from 7 to 13 days in T1 while from 8 to 12 days in T2. The number of females whose eggs hatched was 60% for T1 and 40% for T2. The mean total number of zoeae/female was 3.98 million for T1 and 3.02 million for T2.
Larvae. Two runs have been conducted to compare commercial (T1) and SEAFDEC-developed (T2) probiotic with antibiotic (T3; control) in crab larviculture. Larval mortality in T1 and T2 was apparent at day 6 and 8, respectively. All larvae in T1 and T2 were discarded at day 11 due to mass mortality. Luminescent bacteria count in the rearing water reached up to 104 cfu/ml for T1 and T2 while the count in T3 was less than 102. The survival from zoea to megalopa was 3.8% in T3.
Various shrimp larval formulated diet available commercially and SEAFDEC formulated diet have also been tested for crab larviculture. Crabs fed rotifers served as the control. Larvae in all treatments were fed Artemia starting zoea3 (day 7 or 8). Mass production of larvae in one- and 10- ton tanks is a continuous activity in the hatchery.
Nursery culture of S. serrata in net cages fed formulated diet
S. serrata megalopae stocked in tanks were fed several levels of formulated feed (2g to 6 g/ton/day). After 30 days, the survival in all levels ranged from 20-51%. Highest survival was noted at 6 g/ton/day feeding. This level of formulated diet was used in the succeeding run in comparison with natural food (fish and mussel) alone or in combination.
Highest survival was obtained in crabs fed mussel + formulated diet (40 ± 2.26%) and pellets alone (37.9 ± 2.39%) followed by mussel alone (30.4 ± 2.29%) and trash fish + formulated diet (28.8 ± 1.58%).
Production of mud crab juveniles in different nursery systems
Phase 1. Eight net cages installed in 800 m2 nursery pond were stocked with megalopae at 50 ind/m2 to determine the efficiency of two substrate types. Four of the net cages were provided with ribbon-like zigzag net substrates hanged in the water column (T1) and the other four cages with net substrates positioned on the bottom (T2). Megalopae were fed mussel meat in satiation.
After 30 days, the survival of crabs ranged from 43-53 % in T1 while 23-41% in T2. T1 had mean body weight of 2.0 g while T2 attained 1.63 g. Crabs in T1 and T2 had comparable carapace width (CW).
The high salinity (35-38 ppt) recorded in Phase 1 could have affected the low survival and growth of the crabs.
Phase 2. Crabs harvested in Phase 1 were stocked in 8 units of 20 m2 net cages to compare the performance of crabs at 10 ind/m2 using hanged (T1) and submerged substrates (T2). The pincers were trimmed and treated with iodine prior to stocking. Crabs were fed mussel meat or fish in satiation. After 30 days, survival in T1 (63%) was higher than in T2 (51.6%). Likewise, mean BW and carapace width in T1 (6.08 g and 3.3.6 cm) was higher than in T2 (5.05 g and 3.0 cm).
Mud Crab S. serrata culture using formulated diet in brackishwater ponds
S. serrata juveniles were stocked in pond at 0.3 crab/m2 and fed fish 100% or 50% fish + 50%
formulated diet. Specific growth rate (SGR) of crabs fed fish alone (3.71 g/day) was higher than those fed fish and formulated diet (0.74 g/day).
A separate run is being conducted using four 200 m2 pond compartments to compare the performance of mud crabs fed fish 100% (T1) or 30% fish + 70% formulated diet (T2).
Specific growth rate of crabs in T1 (3.86 g/day) was higher than those in T2 (4.1 g/day). The crabs in both runs will be grown until marketable size (≥400 g BW).
Grow-out production of mud crab in pond and mangrove pens at Dumangas Brackishwater Substation
S. serrata juveniles were stocked in pond and mangrove pen at 5000/ha. After 273 days, crabs in mangroves attained an average weight gain/day of 0.74 g. Survival rate was 10%. Crabs reared in ponds attained an average 1.81 g weight gain/day with a survival rate of 35% after 123 days.
In another run, S. serrata juveniles (5.0 g) were stocked in 2 mangrove pens. Crabs were fed fish by-catch daily. After 104 days crabs had 127 g average body weight and 1.17 g weight gain/day in one pen while 81.8 g body weight and 0.74 g weight gain/day in another pen.
Enhancing adoption of mud crab production technologies in Northern Samar
This newly approved study will be conducted in 4 municipalities in Northern Samar. The project covers the following aspects:
Capacity building. This involves lectures and demonstrations
Refinement of mud crab culture practices. Provision of technical assistance for one full cycle on nursery, grow-out and fattening management, and feed formulation
Stock assessment and policy. This is a research component of the project. The seasonal trends in relative abundance of mud crab by size, sex, volume, stage of maturity, and condition of habitat will be monitored monthly for 2 years in 2 sites (mangroves in enclosed and open bays/estuaries) where crabs are commonly collected. Information will serve as a basis to formulate policies that govern crablet collection.
Monitoring and Evaluation. Assessment of improved practices and the impact on income and livelihood of the farmer beneficiaries
Marketing. Another research component of the project. A baseline survey will be conducted in various municipalities for those engaged in gathering, culturing and marketing of mud crabs.
4. PROPOSED FUTURE ACTIVITIES FOR THE YEAR 2008