Annex 4 SEAFDEC DEPARTMENTAL PROGRAMS OF ACTIVITIES
4. PROPOSED FUTURE ACTIVITIES FOR THE YEAR 2008 1. Planning of the Project Activities
4.2. Expected Outcomes
Program Category: Departmental Program
Program Title: Small-Holder Freshwater Aquaculture Program Responsible Department: Aquaculture Department
Duration of Program: 2006-2010 1. INTRODUCTION
Freshwater fish production through aquaculture dominates farmed finfish production in many Asian countries including the Philippines. There is an increasing demand for food fish from freshwater aquaculture. Sustainable intensification of food production in aquaculture, particularly in marginalized rural communities is a key activity to improve self-sufficiency of these communities.
The focus of the Small-Holder Freshwater Aquaculture Program of AQD is in-line with the thrust of the SEAFDEC Program on Sustainable Fisheries for Food Security in the ASEAN Region
2. PROGRAM 2.1. Objectives
The program objectives are to: (1) refine seed production methods of selected freshwater commodities (e.g. giant freshwater prawn, catfish, carp, and tilapia); (2) develop grow-out production of giant freshwater prawn and catfish in lakes using cages; (3) improve production of both the hatchery and grow-out of selected freshwater commodities; (4) assess the social and economic impact of aquaculture in Laguna de Bay region; (5) verify and commercialize the freshwater aquaculture technologies; and (6) disseminate verified freshwater aquaculture technologies through the publication of manuals, flyers and the conduct of seminars, workshops and hands on-training.
2.2. Program Description
The Program components are the: (i) research, (ii) technology verification and commercialization, and (iii) information dissemination. Some of the activities are in parallel with other existing program of AQD - the Promotion of Sustainable Aquaculture in the ASEAN Region under the Sub-Program Freshwater Aquaculture of Indigenous Species.
3. PROGRESS OF ACTIVITIES IN THE YEAR 2007
Growth and survival of Asian catfish fry reared in net cages with and without supplemental feeding in Laguna de Bay, Philippines
The growth of the native catfish Clarias macrocephalus fry after 6 weeks of rearing in hapa net cages was generally higher in fish fed artificial diet than in fish exclusively fed with natural food from the lake. The specific growth rate and weight gain of the fry stocked at 100pcs/cage and 200pcs/cage did not differ significantly. However, specific growth rate and weight gain were highest in those fry stocked at 100pcs/cage and in those stocked at 200pcs/cage. Survival rate was highest in fry stocked at100pcs/cage without an artificial diet but did not differ significantly from the survival rates of fry in other treatments.
Fish that fed exclusively on natural food showed insects, phyto and zooplankton as well as plant fiber material with Chironomid larvae as major food component in the gut content. The abundance of Chironomid larvae and artificial diet in the culture environment as reflected in the gut content of the fry in both particular treatments suggests that catfish fry voluntarily consumed major food types immediately available for utilization.
Result of the feeding trial with catfish fry reared at 100pcs/cage at various feed levels indicated that growth and survival of fish after 6 weeks of rearing were not significantly different in all treatments.
Refinement of broodstock and hatchery management methods for the commercial
production of freshwater prawn Macrobrachium rosenbergii seedstock I. Production of M.
rosenbergii larvae tolerant to reduced salinities
Postlarvae which metamorphosed from larvae reared in 12 ppt and 6 ppt were stocked in tanks and lake-based net-cages for 5 months culture in early 2007. Results suggest that reducing the hatchery/nursery salinity does not negatively affect the performance traits (growth and survival) of the freshwater prawn. A 5-month growth experiment in tanks and cages was again set up to determine the growth and survival of the selected and control prawns. The F1 postlarvae from the 12ppt group serves as control while the F1 postlarvae from the 6ppt group serves as the selected stock Heritability values after the first round of selection shall be determined at the end of the 5-month rearing period.
Farming of Macrobrachium rosenbergii in modular cages in Laguna de Bay
Experiments are in-progress to determine the effect of horizontally oriented shelters on growth and survival. Generally better growth, survival, daily growth rate and specific growth rate were observed in cages provided with net shelters but the differences between were not statistically significant with P>0.05.
Refinement of broodstock and nursery technology for the commercial production of bighead carp Aristichthys nobilis (Richardson) fingerlings in cages in Laguna de Bay. 1.
Reproductive performance and fry production of bighead carp on different feeding regime The effects of three feeding regimes (3 months feeding before spawning, 2 months feeding before spawning and 1 month feeding before spawning) on reproductive performance of bighead carp in cages were evaluated. Among those induced to spawn, females in treatment 3 (one month feeding before spawning) had significantly higher fertilization rate and hatching rate . However, the total weight of eggs/spawning was significantly higher for bighead carp broodstock in treatment 1 (3 months feeding before spawning). The number of fry produced by the broodsock in treatment 4 (no feeding) was lower than the other three treatments. Growth performance evaluation of fry obtained from the different treatments is in progress.
Economic impacts of aquaculture development in Laguna Lake
Results of the survey have been analyzed. Additional information and secondary data from various government institutions and agencies were also gathered. Initial write ups are on-going and report will be submitted by the 4th quarter of this year.
Integrated fisheries resource management (Rinconada Lakes, Philippines and NSW Australia): Aquaculture and Water Quality Component
Experiments were conducted to evaluate the use of various stocking densities (5, 10 and 15 pcs/m2) and with or without artificial feed for rearing Nile tilapia in cages in Lake Bato and
Bato had an average body weight of 180 to 200 grams after 4 months for those given feed, regardless of stocking density. While those not given any formulated feed and relied solely on natural food had average body weight of 100 g. Water quality in Lake Bato also improved with the onset of the rainy season.
Genetic characterization of commercially important Philippine stocks of freshwater prawn, Macrobrachium sp., using DNA markers (Under GOJ- Promotion of Sustainable Aquaculture in the ASEAN Region)
Methods to extract DNA and PCR-amplify mitochondrial DNA cytochrome oxidase I (COI) from wild and hatchery samples of M rosenbergii have been optimized. Processing of samples for genetic variability analysis is 75% completed. Preliminary results show distinct genetic differences between hatchery and wild stocks based on restriction morphs obtained after digestion with restriction enzymes: HaeIII, RsaI, MspI, EcoRI and Mbo.
Conditions for mtDNA sequencing using primers flanking the mtDNA COI region are now developed and have been optimized. Thus far, mt DNA COI from one hatchery stock and four wild stocks have been sequenced. The wild stocks Leganes and Pampanga are taxonomically M rosenbergii rosenbergii while the Zambales stock’s identity has yet to be confirmed as either M rosenbergii dacqueti or an interspecific hybrid based on the comparison of the sequence analysis. Work on mtDNA sequencing using representative samples from each stock shall be continued with the sequencing of M mamillodactylus samples from Mindanao.
Morphometric characterization and performance evaluation of Macrobrachium rosenbergii stocks and closely related species in found in the Philippines I. Collection, identification and validation of Macrobrachium samples: II. Performance evaluation (Reproductive efficiency) Under GOJ- Promotion of Sustainable Aquaculture in the ASEAN Region
Collection, identification and validation of Macrobrachium samples. Prawn samples from several sites in Luzon and Mindanao were obtained and identities of some of the samples were determined and validated. To date, 14 Macrobrachium species (M australe, M equidens, M esculentum, M horstii, M idae, M jaroense, M lanceifrons, M lar, M latidactylus, M lepidactyloides, M mamillodactylus, M rosenbergii rosenbergii, Mrosenbergii dacqueti, M weberi) found in almost all Philippine regions (except Region VII) have been identified.
Performance evaluation (Reproductive efficiency). The reproductive efficiency of Macrobrachium rosenbergii hatchery (BFAR) and wild (Calumpit) stock given various types of feed and feeding rates (low protein at 2% of the prawn biomass, high protein at 2% of prawn biomass and low protein given ad libitum) was evaluated Results showed differences in the reproductive efficiency of the two stocks especially in terms of the average number of hatchlings per g. female body weight. Hatchery stocks fed low protein fish feed ad libitum had the highest number of hatchlings at 648/g body weight followed by those fed fish feed at 2%
prawn biomass (583/g) and the high protein prawn feed pellets (578/g). On the other hand, wild stocks fed low protein fish feed at 2% prawn biomass had the most number of hatchlings per g female body weight (823/g), followed by low protein fishfeed administered ad libitum (741/g) and finally high protein prawn feed (609/g).
Morphometric characterization and performance evaluation of different Macrobrachium strains and other commercially important freshwater prawns in the Philippines. III.
Performance of different strains of Macrobrachium rosenbergii in grow-out culture in lake-based cages (Under GOJ- Promotion of Sustainable Aquaculture in the ASEAN Region) Post larvae of M. rosenbergii obtained from broodstock from Calumpit (Bulacan) reared in cages in the lake and given various feed types (shrimp feed, tilapia feed, catfish feed); mesh size
of cages (hapa vs. b-net); and shelter (with or without) were evaluated. After two months of culture in the net cages, results showed that feed type, and presence or absence of net shelters had no significant effect on growth and survival of M. rosenbergii. By the sixth month of culture, results showed that mesh size affected survival, with higher rates observed in those reared in hapa net (75%) compared with those in b-net cages (60%). Significantly larger prawns were also observed in the hapa cages (13.2 g mean weight) compared to those in b-net cages (10.5 g). The number and weight of blue-clawed males (BC) were also affected by mesh size with bigger culled out BC in the hapa cages (63 pcs vs 20 pcs). The mean weight of BC was not affected by mesh size. No significant effect on growth and survival as well as the number and weight of BC were observed with feed type and presence or absence of shelter.
Hatchery seed production of the native catfish Clarias macrocephalus
The last spawning trial conducted in May 2007 produced more than 45,000 fry (day-4). Fry were further reared to post-fry and later sold to private growers or used in collaborative projects on nursery and grow-out. A total of 19,700 pcs fry were sold.
Refinement of broodstock and hatchery management methods for the commercial production of freshwater prawn Macrobrachium rosenbergii seedstock: Bioeconomics of freshwater prawn hatchery production in different larval rearing system.
Rearing of freshwater prawn Macrobrachium rosenbergii larvae in two culture systems (green water and clear water) using 100 liters tanks and 1 ton capacity tank was conducted. Based on the results of the second trial, larvae reared in clear water had an average survival of 31.35 % and it took 33 days to reach post larval stage, while larvae reared in green water had an average survival of 34.1 % and it took 28 days to reach post larval stage. In terms of post-larvae produced, the number of prawn larvae reared in green water was higher than that of prawn larvae reared in clear water..
Improvement of fillet yield in Nile tilapia (Oreochromis spp) through farm-based mass selection and interspecific hybridization
Second generation broodstocks selected for improved fillet yield have spawned. F3 fingerlings are now being reared and monitored for growth in terms of improved body girth/depth (potential indicators for increased fillet yield). Results will be used as basis for making a decision on whether selection for increased fillet yield is a heritable trait.
The Binangonan Freshwater Station staff have rendered services to the 4 client entrepreneurs/fish farmers based in Luzon. The activities were holding discussion sessions with clients, site assessment, inventory of status of stocks, etc.
4. PROPOSED ACTIVITIES FOR THE YEAR 2008