Browsing by Author "Nievales, Marie Frances"
Conference paperMF Nievales, R Sibonga & H Figurado - In MRR Romana-Eguia, FD Parado-Estepa, ND Salayo & MJH Lebata-Ramos (Eds.), Resource Enhancement and Sustainable Aquaculture Practices in Southeast Asia: Challenges in Responsible Production … International Workshop on Resource Enhancement and Sustainable Aquaculture Practices in Southeast Asia 2014 (RESA), 2015 - Aquaculture Department, Southeast Asian Fisheries Development CenterVarious post-larval rearing methods were compared to determine which scheme would give the most yield of newly settled (visible) juvenile stage (> 1mm body length). Five types of postlarval rearing methods were tested: T1- planktonic diatom only (Chaetoceros calcitrans, Cc), T2-benthic diatom Navicula (Nsp) as biofilm and concentrate, T3- Navicula as biofilm + Cc, T4Spirulina as paste on settling plate + Cc, and T5- Spirulina (Sp) as paste on settling plates + Nsp concentrate. An experiment was conducted in small (3-li) aquaria using a cohort of Day 14 (postfertilization) sandfish larvae. Simultaneously, three of the 5 post-larval rearing methods (i.e. T2, T3 and T4) were done in medium scale (30-li) aquaria to determine how a conventional method (T2) employed in a pilot sea cucumber hatchery in Central Philippines compared with method observed in Viet Nam (T3) or with a hybrid method (T4). Visible post-settled juveniles were counted weekly for the next three weeks and expressed as percentage yield. After three days of rearing, transparent but visible early settled juveniles were observed. Mean percentage (%) juvenile yield in week 1 was highest in T1 (Cc only)(17% + 1.3) followed by T3 (Sp + Cc) (14% + 1.6) in a 3 li scale. Yield increased and peaked in week 2 especially for rearing methods with Nsp while those without (e.g T1 and T2) declined dramatically by week 3. In the 30-li scale, the highest mean yield was consistent with T5 (Nsp + Cc) until Week 3 (12% + 11.2). The mean juvenile yield on the 2nd and 3rd week were better than the 2% average for this stage or the 2.5% benchmark based on experiences in the Philippines and Viet Nam as indicated in published references.
Size measurement and nutritional condition evaluation methods in sandfish (Holothuria scabra Jaeger) S Watanabe, JM Zarate, JG Sumbing, MJH Lebata-Ramos & MF Nievales -
Aquaculture Research, 2012 - WileyThe aims of this study were to establish an accurate size measurement method and a nutritional condition evaluation method of Holothuria scabra (Jaeger). Although 0.5% KCl and 0.05% MgSO4 did not induce anaesthesia, 2% menthol–ethanol for 20 min was found to be effective and harmless. The anaesthetization significantly reduced the coefficient of variation of the mean body length and weight by 68% and 43% respectively. During starvation, body size and weight decreased concomitantly, resulting in an unchanged condition factor (body weight/volume), suggesting that the condition factor cannot be used as an index of nutritional condition. Protein, cholesterol and carbohydrate concentrations in the body fluid were analysed to study the relationship with starvation. As the protein and cholesterol concentrations initially increased and then decreased during the starvation period, it is difficult to use them as an index of nutritional condition. The carbohydrate concentration showed a gradual one-fold increase during 10 days of starvation, and it may be used as a proxy for nutritional condition; however, further physiological studies are needed. Body fluid density and volume relative to body size gradually increased and decreased, respectively, during starvation. These methods may be used to correctly monitor the conditions of H. scabra in studies for aquaculture and stock enhancement techniques.
Utilization of organic waste from black tiger shrimp, Penaeus monodon, by sandfish, Holothuria scabra S Watanabe, JM Zarate, MJH Lebata-Ramos, MFJ Nievales & M Kodama - In K Tanaka, S Morioka & S Watanabe (Eds.), Sustainable stock management and development of aquaculture technology suitable for Southeast Asia, 2012 - Japan International Research Center for Agricultural Sciences
Series: JIRCAS Working Report; No. 75In Southeast Asian countries, a large proportion of shrimp aquaculture has switched its target species from native black tiger shrimp, Penaeus monodon, to exotic P. vannamei because of frequent viral disease outbreaks. One of the causes of disease outbreaks is thought to be poor water and sediment conditions in the shrimp pond, which aggravate disease symptoms. To establish co-culture methods of black tiger shrimp and sandfish, Holothuria scabra, for possible mitigation of shrimp pond eutrophication and prevention of disease outbreaks, laboratory experiments were conducted at the Aquaculture Department, Southeast Asian Fisheries Development Center (SEAFDEC/AQD) in Iloilo, Philippines. A feeding trial of juvenile H. scabra using benthic diatom, Navicula ramossisima, and powdered P. monodon feed showed that H. scabra do not grow with fresh shrimp feed on a hard substrate. A feeding trial with and without sand substrate with shrimp feed as food showed that the substrates enhance the growth of H. scabra. H. scabra juveniles were found to grow with detritus and P. monodon feces as food sources in tanks. It was also shown that addition of ground oyster shell to the sand substrate enhances the growth of H. scabra when fed with N. ramossisima. Thus, these results suggest that H. scabra can grow by feeding on organic matter present in a P. monodon pond and may be used to mitigate organic load in P. monodon ponds.