Now showing items 54-73 of 1070

    • Article | Short communication

      Bacteria associated with infection at hormone-implantation sites among milkfish, Chanos chanos (Forsskal), adults 

      G Lio-Po, C Pitogo & C Marte - Journal of Fish Diseases, 1986 - Blackwell Publishing
      SEAFDEC Contribution No. 164. Paper presented at the Second International Warmwater Fish Conference at Laie, Hawaii, 5–8 February 1985.
    • Article

      Bacterial diseases in shrimp (Penaeus monodon) culture in the Philippines 

      CR Lavilla-Pitogo & LD de la Peña - Fish Pathology, 1998 - Japanese Society of Fish Pathology
      The hatchery system for Penaeus monodon evolved from the Japanese community culture system to the modified Galveston method and this shift in culture technique triggered the outbreak of diseases due to opportunistic bacteria. Whereas, sporadic infestation with filamentous bacteria and shell disease were the main bacterial diseases seen in earlier larval culture systems, hatcheries using the modified Galveston method experienced disease outbreaks due to systemic bacterial infection. Although several types of vibrios have been implicated in the epizootics, the dominant species seen were non-sucrose-fermenting vibrios, mainly luminescent Vibrio harveyi. To understand the course of infection, the entry of bacteria in the hatchery was investigated by determining the components and additives which encouraged their growth and dominance. As a result, several approaches to prevent and control bacterial disease have been implemented such as water treatment, hygienic spawning and egg handling, maintaining ecological balance within the system, and chemotherapy. In shrimp grow-out culture, early reports of bacterial problems were limited to shell disease, filamentous bacterial infestation and tail rot. In the last quarter of 1993, however, mass mortality associated with massive bacterial infection in the digestive organ of shrimp started occurring and contributed largely to the collapse of shrimp grow-out activities. An epidemiological study was conducted to understand the spread of infection. Several approaches to prevent or control the problem have been attempted such as the use of reservoirs, water treatment, chemotherapy, maintaining ecological balance within the system through the application of probiotics, and other system modifications.
    • Article

      Bacterial flora in the hepatopancreas of pond-reared Penaeus monodon juveniles with luminous vibriosis 

      EM Leaño, CR Lavilla-Pitogo & MG Paner - Aquaculture, 1998 - Elsevier
      Quantification and characterization of bacterial flora in the hepatopancreas (hp) of pond-reared Penaeus monodon juveniles affected with luminous bacteria were conducted in 1994 and 1995. Shrimp samples were taken from 23 grow-out ponds, 14 of which had disease outbreaks. Luminous bacterial (LB) load of the shrimps' hp with (mean=2.4×101 colony forming units (CFU)/hp) and without (mean=0.3×101 CFU/hp) disease outbreaks were comparable during the first 15 days of culture (DOC). During disease outbreaks at 18 to 32 DOC, however, LB load of affected shrimps (mean=9.0×104 CFU/hp) were higher than healthy shrimps (mean=7.0×101 CFU/hp). At 50 to 60 DOC, levels of LB were comparable in older shrimps with or without disease. Total viable and presumptive Vibrio counts were also comparable in both shrimp samples from 1 to 60 DOC. Characterization of the 172 bacterial isolates collected showed that most (90.12%) were Vibrio species dominated by V. harveyi (27.91%), V. splendidus II (13.37%) and V. parahaemolyticus (10.46%).
    • Article

      Bacterial flora of milkfish, Chanos chanos, eggs and larvae 

      RD Fernandez, EA Tendencia, EM Leaño & MN Duray - Fish Pathology, 1996 - Japanese Society of Fish Pathology
      Aerobic bacterial flora of eggs and larvae of milkfish, Chanos chanos, was investigated. Microflora in the incubating water of egg, rearing water of larvae, water source, and larval food was also analyzed.

      Aerobic bacterial flora of milkfish eggs was largely influenced by the bacterial flora in the incubating water. Both in eggs and in the incubating water Pseudomonas species were the dominant bacteria. During milkfish larval rearing, intestinal aerobic bacterial flora was examined at days 1, 3, 7, 10, 15, 18, and 21. Bacterial number in the larvae and rearing water significantly increased during the culture period up to day 18 but dropped significant at day 21. Pseudomonas species were detected from yolk-sac larvae (day 1) as the dominant bacteria, similarly to the normal flora in the rearing water. However, intestinal bacteria were predominated with Vibrio species when the yolk-sac was absorbed on day 3. Larval rearing water, water source, and larval food contained predominantly Pseudomonas species.
    • Article

      Bacterial microbiota of eggs from cage-reared and tank-reared grouper, Epinephelus coioides 

      EA Tendencia - Bulletin of the European Association of Fish Pathologists, 2004 - European Association of Fish Pathologists
      At SEAFDEC AQD, opaque spawned grouper eggs are observed during collection in cage-reared brood stock; while opaque and multi-colored eggs are often observed in tank-reared fishes. This study aimed to investigate the occurrence of these opaque and multicolored eggs and at the same time to compare the bacterial microbiota of eggs from brood stock reared in cages, to those from fish reared in concrete tanks. Grouper eggs from brood stocks reared in cages and tanks were processed for bacterial count and identification. Results showed that total bacterial count (on MA) and presumptive Vibrio count (on TCBS) of eggs from brood stock reared in concrete tanks were lower than those from cage-reared fishes. Aeromonads (for tank-reared) and Pseudomonads (for cage-reared) were the dominant bacteria in the good eggs; while Vibrios were dominant in the bad eggs for both egg sources. Total bacterial count of the egg-incubating medium from the brood stock tanks (104 cfu/ml) was lower than the total bacterial count of water from the cages (107 cfu/ml). Presumptive Vibrio counts of water from the tanks (102 cfu/ml) were lower than those from the cages (106 cfu/ml). The Aeromonads dominated the water from the tanks; while Vibrios dominated those from the cages. Good eggs that did not hatch, turned yellow after 3 days, and pink after 5 days.
    • Article

      Bamboo back disease in tiger shrimp, Penaeus monodon 

      EA Tendencia - Bulletin of the European Association of Fish Pathologists, 2002 - European Association of Fish Pathologists
      This report describes bamboo back disease affecting Penaeus monodon in the Philippines. Affected and normal shrimps were processed for bacterial isolation and histopathology. Morphological changes in the external anatomy were also noted. The cuticle of the abdominal segments of shrimp with bamboo back disease do not overlap properly which gives them a bamboo-like appearance. The appendages are shorter compared with normal shrimps. No bacteria were recovered from the hepatopancreas, lymphoid organ, and hemolymph thus ruling out bacterial infection. Histopathology shows normal hepatopancreas, but the muscle fibers of the abdominal segments are fragmented and necrotic.
    • Article

      Baseline assessment of fisheries for three species of mud crabs (Scylla spp.) in the mangroves of Ibajay, Aklan, Philippines 

      MJHL Lebata, L Le Vay, JH Primavera, ME Walton & JB Biñas - Bulletin of Marine Science, 2007 - University of Miami, Rosenstiel School of Marine and Atmospheric Science
      Stock enhancement through habitat restoration and habitat release have both been considered as approaches to the management of declining Scylla spp. Prior to stock enhancement trials, the present study was conducted to monitor recruitment and yields of three Scylla spp. in ∼70 ha of natural mangroves in Aklan, Panay, Philippines. Results showed that Scylla olivacea (Herbst, 1796) was the most abundant mud crab species, comprising 95% of the catches over the 4 yr sampling period. Size distribution for this species indicated year-round recruitment with peaks in the numbers of smaller, immature crabs during the summer months. The decreasing mean size at capture, yield and CPUE in terms of weight throughout the 4-yr sampling period is an indication that the area has been subjected to heavy fishing pressure. The constant CPUE in terms of numbers of crabs suggests that recruitment is constant, though this is likely to be lower than in other mangrove areas due to the topography of the site with limited access to the open sea, resulting in relatively low crab abundance and yields. Combined with the fidelity of S. olivacea to the mangrove habitat, this indicates a suitable population for investigation of the effectiveness of a hatchery-release program.
    • Article

      Bioactivity of stored luteinizing hormone-releasing analogue (LHRHa) in sea bass, Lates calcarifer Bloch 

      LMB Garcia - Journal of Applied Ichthyology, 1996 - Wiley-Blackwell
      The spawning induction activity of dissolved and pelleted (D-Ala6, Pro9 N ethylamide) luteinizing hormone-releasing hormone analogue (LHRHa) stored for various periods was assessed in mature female sea bass. The spawning response of mature fish was reduced significantly after injection of dissolved LHRHa (20 μg kg−1) stored for more than 90 days in a refrigerator (4–10°C) or for more than 30 days at room temperature (28–30°C). Similar to fish administered fresh preparations of LHRHa, fish spawned successfully after injection of a solution of LHRHa previously frozen, subjected to alternate freezing and thawing, exposed to sunlight or implanted pelleted LHRHa (50 ng kg−1) stored at room temperature for 30–120 days. Loss of hormone bioactivity after prolonged storage may have been due to bacterial growth in solubilized preparations. Injection or implantation of stored LHRHa did not influence egg production among treated sea bass. These results demonstrated the relatively prolonged shelf life of stored LHRHa.
    • Article

      Biodegradition of monochloroacetic acid by a presumptive Pseudomonas sp. strain R1 bacterium isolated from Malaysian paddy (rice) field 

      SN Ismail, AM Taha, NH Jing, RA Wahab, AA Hamid, RV Pakingking Jr. & F Huyop - Biotechnology, 2008 - Asian Network for Scientific Information
      A bacterial strain tentatively identified as Pseudomonas sp. R1 was isolated from a paddy (rice) field that could degrade monochloroacetic acid (MCA) for concentrations ranging from 5 to 40 mM. Quantitative agreement between the amount of MCA introduced and chloride released was also found. MCA dehalogenase activity in this strain was found to be inducible. Cell-free extracts displayed dehalogenating activity with specific halogenated organic compound with no activity on dichloropropionic acid or monochloropropionic acid. The estimated Km values for MCA was 0.14 mM. The optimal pH range for MCA dehalogenase activity (between pH 6.5 and 8.0), whereas the thermal stability profile stable up to 50 °C. The results of our current study demonstrated the potential use of Pseudomonas sp. R1 as suitable biological agent for biodegradation of MCA in contaminated agricultural area.
    • Article

      Biological evaluation of frozen zooplankton as food for milkfish (Chanos chanos) fry 

      CT Villegas & GL Lumasag - Journal of Applied Ichthyology, 1991 - Verlag Paul Parey
      Milkfish fry with an average standard length and weight of 13.88 mm and 3.95 mg, respectively, were reared for 30 days using live and frozen Moina macrocopa and Brachionus plicatilis at feeding densities of 10–20 individuals per ml. Growth, survival and yield were used as indicators of the overall performances of the various treatment groups. Fry fed live M. macrocopa showed gains (both length and weight), growth and survival rates and yields significantly higher than fry fed with other treatment groups (P < 0.05). However, significant reductions in growth and survival rates resulted when fry were fed frozen M. macrocopa. On the other hand, there were no significant differences in growth and survival rates (P < 0.05) in fry fed live or frozen B. plicatilis.

      The results of the current study showed that although milkfish fry could be grown successfully using B. plicatilis, feeding with live Moina significantly improved growth, survival rate and yield (P < 0.05). Frozen Moina was found to be unsuitable as a feed for rearing milkfish fry because it reduced growth rates and increased mortality. Comparisons between live and frozen rotifers have proven the suitability of frozen rotifers as feed for rearing milkfish fry. By freezing surplus rotifers this would permit short term storage in anticipation of high hatchery demand and overcome any unpredictable failures with live cultures.
    • Article

      Biological evaluation of phytoplankton (Chlorella sp., Tetraselmis sp. and Isochrysis galbana) as food for milkfish (Chanos chanos) fry. 

      JV Juario & V Storch - Aquaculture, 1984 - Elsevier
      Phytoplankton cultures of Chlorella sp., Tetraselmis sp. and Isochrysis galbana were used alone as feed to rear separate batches of newly caught milkfish (Chanos chanos) fry (about 21 days old). Ultrastructural studies of fry hepatocytes and pancreatic acinar cells indicated that they cannot directly utilize Chlorella, which has a rigid cell wall. The fry can directly utilize Tetraselmis and Isochrysis, but neither is nutritionally adequate for growth and survival if used as the only feed. Tetraselmis is nutritionally inferior to Isochrysis.
    • Article

      Biological evaluation of three phytoplankton species (Chlorella sp., Tetraselmis sp., Isochrysis galbana) and two zooplankton species (Crassostrea iredalei, Brachionus plicatilis) as food for the first-feeding Siganus guttatus larvae 

      MN Duray - The Philippine Scientist, 1986 - University of San Carlos
      First-feeding Siganus guttatus larvae were given different species of phytoplankton (Chlorella, Tetraselmis, Isochrysis) and zooplankton (oyster trochophores, Brachionus) or a combination of both on the first day when they can feed. None of the phytoplankton species when used as the only food source for the larvae could support life beyond four days from hatching. Brachionus of sizes less than 90 microns was the most suitable food for the first-feeding larvae. A food mixture of the three phytoplankton species and Brachionus resulted in survival rates that were significantly higher than with other treatments. Larval growth, however, did not differ significantly (p>0.05).

      Different Brachionus densities were also used during the first-feeding days. Although the range of 10 to 15 Brachionus per ml gave better survival, no significant difference existed. Growth was slightly greater but not significantly different at higher densities.
    • Article

      Biomass and reproductive states of Gracilaria heteroclada Zhang et Xia collected from Jaro, central Philippines 

      MRJ Luhan - Botanica Marina, 1996 - Walter de Gruyter
      Biomass production and reproductive states were investigated to determine the abundance of Gracilaria heteroclada Zhang et Xia at Jaro, central Philippines from March 1990 to February 1991. Biomass of Gracilaria heteroclada was highest in February (45 g/m2) and lowest in July (1.16 g/m2). Plant fertility was seasonal with the highest percentage of carposporphytic and tetrasporophytic plants occurring in January (48%) and in May (64%) respectively. Seawater temperature was significantly correlated with tetrasporophyte occurrence (r = 0.6586) but not with carposporophyte occurrence. There was no correlation of the occurrence of tetrasporophytes or carposporophytes with salinity or rainfall.
    • Article

      Biomass production, proximate composition and fatty acid profile of the local marine thraustochytrid isolate, Schizochytrium sp. LEY7 using low-cost substrates at optimum culture conditions 

      G Ludevese-Pascual, M Dela Peña & J Tornalejo - Aquaculture Research, 2016 - John Wiley and Sons
      This study was conducted to investigate low-cost substrate alternative and the optimum culture conditions in mass producing the local marine thraustochytrid, Schizochytrium sp. LEY7 isolated from the mangrove leaves of Baybay, Southern Leyte Philippines. Results showed that Schizochytrium sp. LEY7 is able to utilize commercial grade glucose and yeast extract from NaCl-treated baker's yeast as source of carbon and micronutrients respectively. Cost of mass producing the thraustochytrid isolate using the alternative production substrates was substantially reduced. Incubation temperature and salinity levels were the two growth factors significantly affecting the biomass production of the isolate. The short duration of lag phase shown by the isolate suggests a growth advantage in that cells are readily able to adapt to their new environment. Total lipids averaged to 19.4%. Principal fatty acids were palmitic acid (C16:0) with 33.52% and docosahexanoic acid (DHA, C22:6n-3) with 39.92% proportion to total fatty acid. Eicosapentaenoic (C20:5n-3, 1.01%) and arachidonic (C20:4n-3, 0.90%) are present but in relatively lower amount. Our findings showed the potential of low-cost substrate in mass producing the local thraustochytrid isolate, Schizochytrium sp. LEY7 as lipid and polyunsaturated fatty acid source in aquaculture. Biomass production was enhanced by optimizing the culture conditions.
    • Article

      Biomass yield of Isochrysis galbana (Parke; clone T-ISO) and growth of Brachionus rotundiformis (Tschugunoff) using continuous cultivation method 

      MR de la Peña - Philippine Agricultural Scientist, 2014 - College of Agriculture, University of the Philippines Los Baños
      Batch culture of Isochrysis galbana clone T-ISO is difficult due to its unstable biomass production; hence, the effect of continuous cultivation at different dilution rates was investigated to compare its productivity with that of batch culture. Significantly higher total algal cell yield was attained in continuous cultures (1.70 × 108 and 1.03 × 108 cells L-1 at 0.60 d-1 and 0.30 d-1 dilution rates, respectively) compared with batch culture (0.16 × 108 cells L-1); the batch culture did not receive any inflow of nutrients. The amount of protein per cell was similar in both batch and continuous cultures at 0.60 d-1 dilution rate after 24 h and 5 d in both culture systems. Chlorophyll a yield was not affected by dilution rate but decreased as the culture aged. The dry weight yield was also similar in both batch and continuous cultures. The higher nitrate concentration supplemented in the batch culture resulted in higher cell density and elevated protein content of the alga. Rotifer (Brahionus rotundiformis) cultures that received inflow of nutrients from the algal tanks had significantly higher (P<0.05) peak population count (28 and 33 individuals mL-1 at 0.30 and 0.60 d-1 dilution rates, respectively) compared with rotifer cultures that did not receive an inflow of food (18.22 individuals mL-1). The higher biomass yield of T-ISO using continuous cultivation method can increase the population growth of rotifer under tropical conditions.
    • Article

      Breeding and larval rearing of the rabbitfish, Siganus guttatus (Bloch) 

      JV Juario, MN Duray, VM Duray, JF Nacario & JME Almendras - Aquaculture, 1985 - Elsevier
      Females of Siganus guttatus reared to sexual maturity in canvas tanks were induced to spawn by using human chorionic gonadotropin (HCG, Ayerst) at 500 IU/fish or about 2 IU/g body weight. The amount of HCG used depended on the initial mean egg diameter; the smaller the diameter, the more HCG was used. Fish with oocytes characterized by germinal vesicle migration (mean egg diameter ≥ 0.47 mm) spawned without HCG injection. Fertilization and hatching rates for both treated and untreated fish were more than 90%. The larvae were reared to metamorphosis using rotifers from day 2–17, rotifers + newly hatched Artemia nauplii from day 18–20 and rotifers + newly hatched Artemia nauplii + artificial feed from day 21–35. In addition, Isochrysis galbana was introduced to the rearing tanks from day 1–10 and Chlorella sp. and/or Tetraselmis sp. from day 1–35. Survival rates of larvae tended to be lower as the broodstock became older.
    • Article

      Broodstock management and egg production of milkfish, Chanos chanos Forsskal 

      AC Emata & CL Marte - Aquaculture Research, 1993 - Blackwell Publishing
      The milkfish, Chanos chanos Forsskal, industry in the Philippines suffers from a limited supply of wild fry. The demand for milkfish fry has spurred research in artificial propagation to supplement the natural seed supply. Spontaneous maturation and spawning of milkfish beginning at 5 years of rearing in floating net cages or concrete tanks coupled with improved egg collection technique have increased daily egg collection to a maximum of 3 million eggs and provided adequate volumes of eggs for mass fry production. Annual egg collection and number of spawnings were markedly higher in cage-reared stocks older than 9 years old than stocks less than 9 years old. Egg collection of tank-reared stocks were comparable to those collected in cages. As feed constitutes a major portion of the operating expenses for establishing and maintaining milkfish broodstock, further studies must be geared towards defining optimum dietary requirements and ration size for gonadal maturation and spawning. Also environmental manipulation studies must be conducted for year-round spawning. Developments in these areas should ensure the production of maximum numbers of high quality eggs and fry year-round.
    • Article

      Broodstock transplantation: An approach for stock enhancement of the 'kapis' shell Placuna placenta along Panay Gulf, central Philippines 

      JA Madrones-Ladja, ET Aldon & DD Baliao - The Philippine Agricultural Scientist, 2012 - College of Agriculture, University of the Philippines Los Baños
      The Panay Gulf in central Philippines once supported a substantial ‘kapis’ Placuna placenta (Linnaeus) population that was among the six major sources for this species. However, stock depletion began in the late 1980s because of overexploitation and destructive fishing practices. To recover the declining ‘kapis’ fishery along the Gulf, a broodstock transplantation program was initiated in 1999. Results from a survey of the Gulf prior to this program confirmed reports of resource depletion. Four (4) transplantation sites (S) with natural soft-muddy substrata in adjacent coastal towns, namely, Tigbauan (S1 and S2), Guimbal (S3) and Oton (S4) were established and stocked with 3200 (1:1 male to female ratio) sexually mature ‘kapis’ broodstock collected from nearby Negros Island in March–October 1999. Transplant survival along the sites ranged 80–100%. Spontaneous spawning by ‘kapis’ transplants occurred from March 1999 (15 d after first stocking) through May 2000. Larvae (5 larvae per L) began to appear at S1 15 d after transplantation and progressively increased in density to 23 larvae per L in November 1999. During this period, local divers reported big patches of ‘kapis’ juveniles [shell length (SL), 38 ± 11 mm] at S4. Sex ratio of recruits was 3:2 (male: female). Larvae became abundant off the nearby coasts with a strong recruitment pulse at 160 larvae per L at S4 by January 2000. Likewise, transplants taken to the laboratory were induced to spawn by photochemical method, and thus validated the spawning that occurred in transplantation sites. Juvenile recruits were of variable sizes, indicating that spawning was not simultaneous. Sexually mature juvenile recruits (40% female, 90% male) were already observed in January–February 2000. The recruitment apparently resulting from these transplants was local, dispersion ranging from zero to a few kilometers distance from transplantation sites. ‘Kapis’ harvest began in 2007 for local market consumption while commercial harvest was done in 2010 with approximately 600 tons.

      The repopulation of ‘kapis’ along Panay Gulf after a decade indicated the success of the restocking program which was attributed to the suitability of the species, reproduction of transplants and the proper management of the newly established resource by the coastal fishers who are members of a local organization (FARMC) with the support of local government units (LGUs).
    • Article

      Butylated hydroxytoluene: its effect on the quality of shrimp diet stored at various temperatures and on growth and survival of Penaeus monodon juveniles 

      MN Bautista-Teruel & PF Subosa - Aquaculture, 1999 - Elsevier
      Shrimp diets with and without the antioxidant, butylated hydroxytoluene (BHT) were stored at 10°, 20°, 28°–30°, and 40°C for 10 weeks. To monitor lipolysis and lipid oxidation, free fatty acid (FFA) content, peroxide values (PVs), and malonaldehyde (MAL) levels were measured from the extracted lipids of the stored diets. Fatty acid levels of the diets increased between the initial and final samplings and the increase was higher (8.4%) in diets without BHT stored at 40°C after 10 weeks. Peroxide values of the extracted lipids were low and fluctuated monthly between 2.2 and 7.4 mmol/kg fat. MAL levels increased in diets with and without BHT except those stored at 10°C for 4 weeks. Diets with BHT stored at 10°C had the lowest (8.7 mg MAL/kg fat) MAL levels and diets without BHT stored at 40°C for 10 weeks had the highest (16.9 mg MAL/kg fat). Shrimp fed diets with BHT gained 5.7–6.4× their initial weight after 10 weeks of rearing. Their growth was significantly better than those fed diets without BHT (4–6×) during the 60-day culture period. Survival was significantly higher in those fed diets with BHT (87–88%) than those without BHT (75–85%). No hepatopancreatic lesions were seen in shrimp samples fed diets with and without BHT and stored at various temperatures. The incorporation of BHT in shrimp feed is necessary if the feed is to be stored at 40°C for 10 weeks.
    • Article

      Cage culture of Kappaphycus alvarezii var. tambalang (Gigartinales, Rhodophyceae) 

      AQ Hurtado-Ponce - Journal of Applied Phycology, 1992 - Springer Verlag
      Kappaphycus alvarezii var. tambalang was cultured in a 3 × 3 m bamboo raft installed inside a 4 × 4 m floating net cage of Lates calcarifer (sea bass) broodstock at SEAFDEC Sub-station Igang, Guimaras, Philippines, from December 1989 to May 1990. Growth and production of K. alvarezii var. tambalang was influenced by the culture months. The highest growth rate and production were recorded in January and May, respectively, while the lowest growth rate and production were observed in March. Average growth rate (wet weight) ranged from 3.72 to 7.17% day-1, while production ranged from 575.5 to 2377 g m-1 line-1. A total production of approximately 123 t (fresh) or 37 t (dried) ha-1 in the 5-month harvest season was produced from this culture system. Cultivation ofK. alvarezii var. tambalang in cages is possible, which indicates that seaweeds can be grown with carnivorous finfish, a practice which is still untapped.