Now showing items 1-20 of 25

    • Conference paper

      2010 and beyond: better seeds for sustainable aquatic food production in Asia. 

      MRR Romana-Eguia & EGT de Jesus-Ayson - In BO Acosta, RM Coloso, EGT de Jesus-Ayson & JD Toledo (Eds.), Sustainable aquaculture development for food security in Southeast Asia towards 2020. Proceedings of the Regional Technical Consultation on Sustainable Aquaculture Development in Southeast Asia Towards 2020, 2011 - SEAFDEC Aquaculture Department
      Asia is a major contributor to world aquaculture production. Most Asian countries have maintained their rank in the ten top aquatic food producing nations after developing refined techniques for major commercially important aquaculture species and promoting an increased awareness on the merits of using quality seeds (genetically enhanced or otherwise) as supplied in sufficient quantities. Quality seedstock simply means fit, clean , uniformly-sized seeds which could be eggs, fry, fingerling, juveniles and/or plantlets (for seaweeds) that subsequently express good performance attributes during culture. Beneficial traits refer to good color, shape, growth, efficient feed conversion, high reproduction, tolerance and survival when exposed to stressors (e.g. diseases, poor and/or extreme environmental conditions). Such traits are mostly heritable, hence, quality seeds are usually assumed as produced only by mating stocks perceived or proven to be genetically superior. Some bloodstocks may be genetically mediocre but if bred and manage properly through efficient farm protocols (suitable hatchery, nursery feeding and water management methods), may also produce good quality seeds. Success in the sustainable production of aquatic species for human consumption depends primarily on the availability of seedstock and adoption of optimal husbandry techniques among others. With the intensification of aquaculture systems and the environmental challenges such as those resulting from climate change, it is wise to continue considering both factors -- genetic quality and culture management as equally important in ensuring a steady production of good quality seeds and later, marketable products from aquaculture. Views on what, how and why better quality aquaculture seeds should be produced evolve as times change. To understand these concerns, this paper will cover: (a) the present state of fish seed production in Asia, (b) recent and current seedstock production issues that require attention, and (c) recommendations on how to further enhance aquaculture production in the region in the next decade through better quality seedstock.
    • Conference paper

      Application of DNA-based markers in stock enhancement programs 

      MRR Romana-Eguia - In JH Primavera, ET Quinitio & MRR Eguia (Eds.), Proceedings of the Regional Technical Consultation on Stock Enhancement for Threatened Species of International Concern, Iloilo City, Philippines, 13-15 July 2005, 2006 - Aquaculture Department, Southeast Asian Fisheries Development Center
    • Article

      Development and characterization of nine novel microsatellite markers for the milkfish Chanos chanos 

      BS Santos, MRR Romana-Eguia, ZU Basiao & M Ikeda - Conservation Genetics Resources, 2015 - Springer Verlag
      The milkfish, Chanos chanos, is an important aquaculture resource in Southeast Asia. Using NGS data, 72 microsatellite markers were developed. PCR product confirmation using agarose gel electrophoresis allowed the identification of 24 utilizable markers. Milkfish samples (n = 48) from a hatchery stock in Palawan, Philippines were analyzed for genetic variability at the aforementioned 24 loci. Consequently, nine of these microsatellite loci were noted to have high success rate in amplification, exhibited polymorphism with 19 maximum number of alleles and no null alleles. These are the first microsatellite markers to be developed and characterized for C. chanos that will efficiently enable genetic stock delineation and monitoring as well as marker-aided genetic improvement research.
    • Article

      Domestication of the mud crab Scylla serrata 

      ET Quinitio, JJ de la Cruz, MRR Eguia, FD Parado-Estepa, GS Pates Jr. & CR Lavilla-Pitogo - Aquaculture International, 2011 - Springer Verlag
      The significant decrease in wild mud crab population highlights the need to manage the resources and domesticate crabs. This paper presents the initial results of the domestication of mud crab Scylla serrata aimed at producing good-quality captive broodstock. The analysis of the genetic structure of the base population was done as a prerequisite for domestication. Adult S. serrata from the northern to southern parts of the Philippines (Cagayan, Camarines, Samar, and Surigao) were obtained for genetic diversity analysis and domestication. Analysis of molecular variance showed that differences in the genetic variability between the four populations were not significant. Moreover, no significant deviation from Hardy–Weinberg Equilibrium was observed in each sample population and even in pooled populations. Body weight was positively correlated with the carapace width. Second spawning occurred 41–46 days after the first spawning and 34 days from second to third spawning. However, there was a decrease in the number of zoea in repeat spawnings. Twenty-four first-generation (F1) families were produced from the four sites. The duration from spawning of the base population (P0) to attainment of broodstock size F1 was 10–14 months. Four second-generation (F2) families were produced after 11–12 months. Up to the F2, crabs tested negative for six viruses: white spot syndrome virus, infectious hypodermal and hematopoietic necrosis virus, gill-associated virus, yellow head virus, Taura syndrome virus, and infectious myonecrosis virus. The reproductive performance of P0 was comparable to the succeeding generations. Several families were obtained from one population in a year. However, due to the cannibalistic behavior of crabs, more space is required for the nursery and grow-out phase. The domestication of S. serrata is the first study done on any mud crab species in the Indo-west Pacific region. The initial results would serve as guide to understand and eliminate the barriers to mud crab domestication. The breeding technology developed from this study will support the production of good-quality seedstock for farming.
    • Freshwater aquaculture for rural communities 

      MRR Romana-Eguia & RV Eguia - In Training Handbook on Rural Aquaculture, 2009 - Aquaculture Department, Southeast Asian Fisheries Development Center
    • Meeting report

      The freshwater prawn research at SEAFDEC/AQD. 

      MR Eguia - 2005 - Aquaculture Department, Southeast Asian Fisheries Development Center (SEAFDEC/AQD)
      Research and commercial production of the freshwater prawn, Macrobrachium sp., in the Philippines are yet not well-developed. Although studies on Macrobrachium sp. (or ulang as it is locally known), started at the Binangonan Freshwater Station (BFS) of SEAFDEC/AQD in the mid-1980s, research efforts were discontinued soon thereafter because of: (a) inadequate technical skills; (b) problems with larval rearing and the domestication of wild stocks; and (c) the Macrobrachium sp. is being considered in the Philippines as a low priority species in contrast to commercially important freshwater commodities like tilapia and milkfish.

      That was two decades ago and in retrospect, researches continued and the freshwater prawn in the Philippines could have been successfully domesticated and current problems concerning the limited aquaculture production of genetically depauperate non-indigenous stocks could have been resolved. With the renewed interest in the culture of alternative species like the freshwater prawn, researchers at the Binangonan Freshwater Station (BFS) started to conduct some studies on the refinement of breeding, larval rearing and culture of Macrobrachium rosenbergii since 2003.
    • Article

      Genetic assessment of milkfish (Chanos chanos Forsskal) stocks based on novel short tandem repeats for marker-aided broodstock management 

      MRR Romana-Eguia, BS Santos, M Ikeda, ZU Basiao & A Kijima - Aquaculture Research, 2018 - John Wiley and Sons
      Milkfish hatchery broodstock are either from on-grown wild-caught or hatchery-produced fry/juveniles. To determine if a marker-assisted management scheme can be formulated for improved milkfish hatchery production, milkfish stocks were genetically characterized using nine novel short tandem repeats or microsatellites. Eight wild-bred Philippine stocks (CLA, CUR, CAM, SIH, SBH-I1, HH, PAL and ZH-P0), four hatchery-bred stocks (SBH-I2, SBH-D, BoH and ZH-F1), two farm stocks of known mixed lineages (SPH and BDH) and one Indonesian hatchery-bred stock (WJH) were assessed. WJH was included since milkfish fingerlings from Indonesia reared in Philippine farms could be developed into future broodstock. Mean allelic richness (Ar) was highest in wild-bred stocks (9.5) and lowest in hatchery-bred spawners (9.1). Mean expected heterozygosities (He) were relatively similar in all stocks with wild-bred stocks slightly higher (0.67) than the others. An analysis of molecular variance indicated significant yet low genetic differentiation among stocks (FST = 0.013; p = .000) where variation (98.6%) was explained by intra-stock differences. In some of the domesticated stocks, reductions in mean allelic richness were observed in first generation hatchery broodstock (e.g. ZH-F1; Ar = 8.3), compared with their founder stock (e.g. ZH-P0; Ar = 9.4). The Indonesian stock was similar to local wild-bred stocks based on genetic variability indices; thus, it might be likely that the local stocks’ fitness traits could be comparable with the imported milkfish stock which has been perceived to be better. The quality of locally available farmed milkfish and prospects of formulating a broodstock management scheme for the production of good quality milkfish seedstock are herewith discussed.
    • Article

      Genetic changes during mass selection for growth in Nile tilapia, Oreochromis niloticus (L.), assessed by microsatellites 

      MRR Romana-Eguia, M Ikeda, ZU Basiao & N Taniguchi - Aquaculture Research, 2005 - Blackwell Publishing
      Two control (C1 or first control generation, and C4 or fourth control generation) and three selected (S1 or first selected generation, S2 or second selected generation, S4 or fourth selected generation) stocks of Chitralada Nile tilapia were analysed for microsatellite variation to determine the effect of size-specific mass selection on genetic variability. Genetic variation based on five microsatellite loci (UNH123, UNH147, UNH172, UNH222 and UNH216) showed a slightly higher allelic diversity in the selected stocks (7.4–10 alleles) than in the control stocks (6.8–8.8 alleles). Apparent reductions in the mean number of alleles and He values were noted in successive generations of both control and selected lines. Significant deviations from Hardy–Weinberg equilibrium because of an excess of homozygotes indicated inbreeding in all control and selected stocks. Although estimated inbreeding levels were not significantly different among selected and control lines based on Welch's t-tests, the increase in the degree of inbreeding within the selected line was higher (107.9%) than the control line (64.2%) after four generations. The implications of these results on the management and conservation of genetic diversity in improved breeds are discussed, while the importance of monitoring and minimizing inbreeding are likewise emphasized.
    • Article

      Genetic diversity in farmed Asian Nile and red hybrid tilapia stocks evaluated from microsatellite and mitochondrial DNA analysis 

      MRR Romana-Eguia, M Ikeda, ZU Basiao & N Taniguchi - Aquaculture, 2004 - Elsevier
      We analyzed microsatellite and mitochondrial DNA restriction fragment length polymorphism (mtDNA-RFLP) in two domesticated (NIFI and Israel) and four genetically improved (GIFT, GMT, FAC-selected and SEAFDEC-selected) Nile tilapia (Oreochromis niloticus) as well as five red hybrid tilapia (Oreochromis mossambicus × O. niloticus) stocks (BFS, FACred, NIFIred, HL, and PF) farmed in Asia. Microsatellite variation at five loci (UNH216, UNH172, UNH123, UNH147, UNH222) was more informative in characterizing stock differences than the mtDNA-RFLP markers that were based only on 14 restriction morphs. Contemporary microsatellite data showed that GIFT Nile tilapia had the highest mean expected heterozygosity (H>e=0.813), while GMT had the lowest (He=0.666). The unselected NIFI stock and SEAFDEC-selected were genetically similar, while GMT differed significantly from the other Nile tilapia stocks. Among the red tilapias, NIFIred had the highest He (0.715), while BFS had the lowest variability (He=0.567). The Taiwanese red tilapia HL and Thai NIFIred were genetically similar. Except for NIFI, most of the Nile and red tilapia stocks exhibited remarkably significant homozygote excess relative to Hardy–Weinberg Equilibrium (HWE), suggesting some degree of inbreeding. Asian Nile tilapias were more genetically diverse (pooled He=0.791; mtDNA nucleotide divergence value dA=0.009) than the red tilapias (pooled He=0.697; mean dA=0.004). This slight divergence between the Nile and red tilapias was also seen in the analysis of molecular variance (AMOVA; FCT=0.0018) and in genetic distance and nucleotide divergence dendrograms. However, the AMOVA revealed that the greater percentage of variation (99.33%) in the total genetic diversity of the surveyed stocks is principally due to differences at the individual level and not between nor within groups. The significance of these results is that they reflect and lead to new inferences regarding the selective breeding and culture methods used in managing these farmed stocks.
    • Article

      Genotype environment interaction in the response of three strains of Nile tilapia to poor nutrition 

      MRR Romana-Eguia & RW Doyle - Aquaculture, 1992 - Elsevier
      Experiments were conducted to determine the effects of poor nutrition on the growth of three Oreochromis niloticus strains fed protein-deficient diets. Four-week-old fry from the three "test" strains were paired with a fourth "reference" strain of tilapia (red) of the same size and stocked in 60-1 aquaria. The treatment lasted 6 weeks, with fish being fed commercial fish feed crumbles for the first and last 2-week periods and rice bran during weeks 3 and 4. Control fish were fed commercial diet throughout. Both control and treatment fish were fed at 20% of fish biomass per day. Lengths and weights were measured every 2 weeks.

      Significant strain effects were noted when the growth of test fish over the whole experimental period was analysed by analysis of covariance using the reference fish growth as a concomitant variable. The relative growth of the three test strains differed at each feeding phase. The NIFI strain grew best during the commercial feed phases, the Israel strain performed best during the rice bran phase while the CLSU strain, regardless of the type of nutritional environment, usually ranked last. Different performance rankings at each feeding phase represent strong genotype X environment interaction among these commercially important lines. This was statistically confirmed by analysis of covariance of the growth of the Israel and NIFI strains during the different feeding phases using the reference strain as a covariate.
    • Conference paper

      Growth and survival of nile tilapia (Oreochromis niloticus) juveniles fed diets with varying levels of irradiated chitosan 

      K Gonzales, MN Corpuz & MRR Romana-Eguia - 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 Center
      Chitin is a natural biopolymer and the second most abundant after cellulose. Chitosan, a derivative of chitin which is soluble in acidic aqueous media, is used in many applications like food, cosmetics, biomedical and pharmaceutical products. It is used in agriculture for enhancing growth in crops while in aquaculture, chitosan is believed to improve the immune response of fish to stress-inducing agents, thus enhancing survival and possibly growth. This preliminary study was conducted to investigate the effects of various concentrations of irradiated chitosan on the growth performance of Nile tilapia, O. niloticus. Fish was fed with a control diet and three formulated diets containing increasing levels of irradiated chitosan (10g, 20g and 50g kg-1). Juvenile O. niloticus was fed once daily for 21 days. The ration was based on 5% of the fish biomass. Tilapia fingerlings (n=30 per tank) of uniform size were randomly distributed in four experimental groups each with three replicates following a completely randomized design. Growth and food utilization parameters were measured. Specific growth rate (SGR), mean weight gain (MWG), mean length increment (MLI) and feed conversion ratio (FCR) were computed and analyzed using ANCOVA. Results from the feeding trials showed no significant difference (P>0.05) in the different performance parameters under the different fish feed treatments. MWG, MLG, SGR and FCR varied in the stocks fed different fish feed treatments but with no significant differences. The results also showed 45-62% survival ratio. These suggest that although there is no significant difference between treatments and control, irradiated chitosan-supplemented diets do not retard the growth of O. niloticus. Chitosan should be studied further to determine how it can improve the growth performance, feed utilization and immune response of Nile tilapia.
    • Article

      Growth comparison of Asian Nile and red tilapia strains in controlled and uncontrolled farm conditions 

      MRR Romana-Eguia, M Ikeda, ZU Basiao & N Taniguchi - Aquaculture International, 2010 - European Aquaculture Society
      Growth of several genetically improved Nile tilapia (GIFT or Genetically Improved Farmed Tilapia, FaST or Freshwater Aquaculture Center Selected Tilapia, SEAFDEC-selected) and domesticated red tilapia (BFS or Binangonan Freshwater Station, NIFI-red or National Inland Fisheries Institute red, HL or Hacienda Luisita) stocks were compared in controlled (tank) and uncontrolled farm conditions (lake-based cages) with unselected NIFI or Chitralada Nile tilapia as control. Specific growth rate differed significantly (P = 0.009) in tank-reared Nile tilapia stocks where GIFT grew best at 1.358%/day followed by FaST (1.307%/day), control stock NIFI (1.257%/day) and SEAFDEC-selected (1.202%/day). Genetic effect explained 84.4% of the variance in growth of Nile tilapia in tanks. Although Nile tilapia growth in cages followed the same trend where GIFT grew best at 1.570%/day, no significant stock differences (P = 0.479) were noted. Meanwhile, red tilapia reared in either tanks or cages showed no significant stock differences in terms of growth. However, survival of the red tilapia stocks in cages differed significantly with HL having the highest percentage survival at 93.3%. The different growth responses of the Nile tilapia stocks especially under controlled (tank) farm conditions were largely due to genetic factors (stock differences).Under uncontrolled farm conditions, environmental factors were generally observed to have also affected the survival and to some extent, the growth of Asian Nile and red tilapia stocks.
    • Article

      Growth of five Asian red tilapia strains in saline environments 

      MRR Romana-Eguia & RV Eguia - Aquaculture, 1999 - Elsevier
      Growth of five Asian red tilapia strains (BFS, NIFI, FAC, PF and HL) were evaluated in brackish and seawater. Eight-week-old juveniles from the five test strains were size-matched with similarly aged Oreochromis mossambicus which served as internal reference. Fish were stocked at a ratio of 15 test:15 reference in 100-l tanks supported by a recirculating system. Commercial feed was given twice daily at 10-20% of the fish biomass. Growth, measured from length and weight increment at 10 weeks, was recorded. Statistical analyses on mean specific growth rates showed significant differences among the strains reared in seawater. The Philippine strain PF grew best in seawater while the Thai strain NIFI performed well in brackishwater. In the Philippines, red tilapias are farmed in intensive freshwater culture systems by few aquaculturists. Results of this study indicate that some Asian strains can be developed for use in more sustainable brackish and seawater culture systems.
    • Article

      Growth response of three Oreochromis niloticus strains to feed restriction 

      MRR Eguia & RV Eguia - The Israeli Journal of Aquaculture-Bamidgeh, 1993 - Society of Israeli Aquaculture and Marine Biotechnology
      Growth of fry from three test strains of Nile tilapia (CLSU, ISRAEL and NIFI) fed restrictively and nonrestrictively were compared. Four-week old fry were matched for size with similarly aged red tilapia fry which served as an internal reference. Fish were stocked in 60l aquaria at a ratio of 25 tests:25 reference fish. Test fish were fed commercial fish feed ad libitum during the initial and final two weeks and rations of the same feed at 10% of the fish biomass during weeks 3 and 4. Control fish were fed commercial fish feed ad libitum throughout the six week experiment. Although feed restriction retarded growth in all three test strains, growth differed significantly between strains. Under both restrictive and nonrestrictive feeding regimes, the ISRAEL strain grew better than the CLSU and NIFI strains.
    • Conference paper

      Incidence and causes of mass fish kill in a shallow tropical eutrophic lake (Laguna de Bay, Philippines) 

      ML Cuvin-Aralar, AE Santiago, AC Gonzal, CB Santiago, MR Romana-Eguia, SF Baldia & F Palisoc Jr. - In 9th International Conference on the Conservation and Management of Lakes. Conference proceedings, 2001 - Shiga Prefectural Government
      Mass fish kills in Laguna de Bay, the largest lake in the Philippines, has been reported as early as in the 1930’s. With the introduction of and development of aquaculture in this lake, considerable attention and concern was focused on the problem. Records of mass fish kill in the lake mainly from unpublished sources and reports from fisherfolk were reviewed and the causes categorized. The data covered the period 1972 to 1998. Among the commercially important fish species affected were milkfish (Chanos chanos), Nile tilapia (Oreochromis niloticus), bighead carp (Aristichthys nobilis), snakehead (Channa striata), catfish (Clarias macrocephalus and C. batrachus, Arius manilensis), silver perch (Terapon plumbeus) and goby (Glossogobius giurus). The first three species are widely used in aquaculture and the rest are important in open water fishery. Sixty percent of mass fish kill incidents were due to low dissolved oxygen with more than half of these cases associated with blue-green phytoplankton blooms. Fish kills due to pollution from agriculture and industries, fish pathogens and other causes are also discussed. The incidence of mass fish kill reached its peak between 1977 to 1986. Records show that the most number of fish kills (80%) occurred between the months of May to September. The lakeshore towns in the central arm of the lake had the highest incidence of fish kill reported with 46% and followed by the west arm of the lake with 38% of all fish kills recorded.
    • Conference paper

      Marker-aided genetic stock management: prospects in Philippine aquatic biodiversity conservation and aquaculture 

      MRR Romana-Eguia, M Ikeda & A Kijima - 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 Center
      With the advent of DNA marker-based technologies and applications, genetic stock assessment incorporating molecular marker information has become an important tool in managing resources both for aquaculture and stock enhancement. Local initiatives toward this end have been undertaken by several research and academic agencies particularly those with access to advanced molecular genetic laboratory facilities both in the Philippines and in collaborating foreign institutions. Funds coming from the Philippine Department of Science and Technology and/or international research grants have supported work on commercially valuable species such as tilapia, shrimp, mud crabs, abalone, milkfish and some high value marine fishes with a view of utilizing and in the process, demonstrating the significance of more scientific microlevel assessment of stocks. Information drawn from marker-aided genetic stock evaluation can contribute to a better understanding of the impact of how proper stock management can be more effectively achieved and how this method can gradually translate to improved yields both from culture and fisheries. This paper covers a review of the status of this technology as applied to ongoing fish conservation and aquaculture production efforts in the Philippines.
    • Book chapter

      On-farm feed management practices for Nile tilapia (Oreochromis niloticus) in the Philippines 

      MRR Romana-Eguia, MA Laron & MR Catacutan - In MR Hasan & MB New (Eds.), On-farm feeding and feed management in aquaculture, 2013 - Food and Agriculture Organization
      Series: FAO fisheries and aquaculture technical paper; No. 583
      The contribution of the Philippines to tilapia production in Asia has increased steadily in the past five years as it addresses hunger and poverty alleviation in the region. Commercial tilapia aquaculture in the Philippines has improved as farmers have become aware of the importance of adopting innovative husbandry technologies. These include the use of intensive culture, using novel feed ingredients, improving the quality of industrial aquafeeds, adopting cost- effective feeding strategies and efficient pond fertilization methods, and culturing improved genetic strains. A case study was conducted to: a) assess current tilapia feed management practices; b) determine recent nutrition-based innovations that include the use of alternative feed ingredients, the adoption of nutritionally complete commercial tilapia feeds, and improvements to feed management practices; and c) evaluate these factors in terms of improved production efficiencies. Thirty-two farmers from selected tilapia cage hatcheries, pond hatcheries, grow- out cages and ponds in Regions III and IV-A (known major tilapia producing regions in the Philippines) were interviewed. The issues addressed included their farm management practices, with particular focus on tilapia feed preferences; quality, procurement and storage methods; and feeding strategies. Their responses were collated and analysed in the context of information simultaneously gathered from the scientific literature, popular publications and relevant websites. The results from the case study highlight the importance of farmers being trained and remaining well-informed about recent improvements in feed technologies and the use of efficient cost-saving feeding strategies to optimize the production of seed and marketable tilapia. Recommendations on how to increase tilapia production through improved feed and feed management practices are described. Finally, recommendations for local regulatory agencies to implement aquafeed quality and nutrient standards are provided.
    • Conference paper

      Optimization of feeding and growth conditions for hatchery-bred larvae of indigenous Philippine silver perch, Leiopotherapon plumbeus (Perciformes: Terapontidae) 

      JA Añano, F Aya, MN Corpuz & MRR Romana-Eguia - 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 Center
      The Philippine silver perch, locally known as ayungin, is an endemic fish species and is considered as a potential candidate for aquaculture and for stock enhancement. However, high mortality associated with early larval stages presents a significant bottleneck to its latent commercialization. Culture experiments considered interactions among prey proportions, growth conditions and their consequences on fish growth performance and survival. Two phases of the experiment were conducted: (1) a short duration feeding trial utilizing different prey proportions of Brachionus calyciflorus and Moina macrocopa and (2) an indoor larval rearing technique that ensured optimum growth and survival of juveniles. Findings of this research will be used to propose an efficient rearing strategy addressing the aquaculture of this indigenous species.
    • Article

      Paralytic shellfish poisoning toxin accumulation in shellfishes collected from various habitats in Murcielagos Bay, Philippines during harmful algal blooms occurrence 

      RJA Narceda, UM Montojo, MRR Eguia & GL Sia Su - Advances in Environmental Biology, 2014 - American-Eurasian Network for Scientific Information (AENSI)
      This study aims to determine whether the habitat of bivalves plays an influence in the occurrence of tropical shellfish toxicity during toxic red tide bloom occurrences in Murcielagos Bay, Misamis Occidental, Philippines. Various shellfish species were collected during the occurrence of red tide blooms. The type of habitat and the shellfish toxicities were investigated. Likewise, the phytoplankton profile in the seawater column was assessed. Results of our study revealed that the occurrence of shellfish toxicities was habitat specific in spite of the fact that the causative organism Pyrodinium bahamense var. compressum was present in low concentrations in the sampling sites. Shellfish collected from sea grass, coralline area, and seafloor habitats were notably susceptible against the paralytic shellfish poisoning toxin contamination compared to those samples obtained from soil substrate. Continuous monitoring of areas that are affected with shellfish toxicity must be conducted so as to safeguard the general public’s welfare dependent on these resources.