Now showing items 697-716 of 1074

    • Article

      Natural spawning, egg and fry production of milkfish, Chanos chanos (Forsskal), broodstock reared in concrete tanks 

      AC Emata & CL Marte - Journal of Applied Ichthyology, 1994 - Blackwell Publishing
      Gonadal maturation, rematuration, and spawning of nine- (1982 stock) and ten-year-old (1981 stock) milkfish reared in 150 and 200 m3 concrete tanks were observed in 1990 and 1991. From 23 September to 9 November 1990, the 1981 stock spawned 15 times with an average daily collection of 61,000 ± 21,000 eggs. From 4 larval rearing trials, the mean overall survival rate (from eggs to 21 -day-old fry) was 9.68 ± 4.3%. From 25 Aril to 31 October 1991, the stock spawned a totaf of 108 times. Mean daily egg collection increasef to 305,000 ± 32,000. Successful rearing trials conducted during the latter part of the spawning season had a mean overall survival rate of 17 ± 3% (n = 17) indicating that mass fry production techniques can be improved. Spawning of milkfish broodstock in concrete tanks provides an alternative to other existing methods of seed production.
    • Article

      Nature parks, museums, gardens, and zoos for biodiversity conservation and environment education: the Philippines 

      T Bagarinao - AMBIO: A Journal of the Human Environment, 1998 - Springer Verlag
      Public consciousness about biodiversity and the environment, and their importance for sustainable development is not widespread in the Philippines. This article advocates nonformal environment education through nature recreation as a means toward 'greening, the mind and the spirit of the citizens. Information is provided about biodiversity, and the status and potential of nature parks, museums, gardens, and zoos in the country. Many of the 116 national parks and protected areas have been exploited for products and energy, and only some provide for recreation-cum-education. The Philippines has no national botanical garden, zoo, or aquarium, and the National Museum is not the proud institution that it should be. Some universities have small museums, botanical gardens, and other biodiversity exhibits for instruction and research, but these and the few zoos and wildlife centers are poorly funded or managed.
    • Article

      Nature's subsidies to shrimp and salmon farming 

      RL Naylor, RJ Goldburg, H Mooney, M Beveridge, J Clay, C Folke, N Kautsky, J Lubchenco, J Primavera & M Williams - Science, 1998 - American Association for the Advancement of Science
      Although many fisheries stocks have declined precipitously throughout the world, fish farming--and especially shrimp and salmon farming--has boomed. The increasingly large scale of these enterprises is now having unforeseen ecological consequences on ocean resources through habitat destruction, effluent discharge, exotic species introductions, and heightened fish catch for feed use. Ending unsustainable production practices will require reorienting regulatory policies and fiscal incentives in shrimp- and salmon-producing counties, and enhancing restrictions on environmentally unsound practices.
    • Article

      Net mesh size affects production of giant freshwater prawn Macrobrachium rosenbergii cultured in lake-based cages 

      MLA Cuvin-Aralar, AG Lazartigue & EV Aralar - Journal of Applied Ichthyology, 2013 - Wiley
      Cage culture of freshwater prawns in open waters is prone to the entry of predators and competitors that particularly hamper production. This study was conducted to determine how smaller net mesh sizes to reduce entry of unwanted species inside the cages affects the production of Macrobrachium rosenbergii in lake-based cages. Juvenile prawns were stocked in cages (7 × 7 × 1.5 m) of two net mesh sizes at 10 individuals m-2 and cultured for 10 months in a shallow eutrophic lake in the Philippines. The two net mesh sizes were either 5 mm-mesh B-nets or and 1 mm-mesh Hapa nets. Each treatment had four replicates each and was fed based on biomass with commercially formulated feed. Monitoring of various production parameters was done during the two phases of culture: batch phase on days 63 and 127 and the selective harvest phase on days 187, 219, 253, 281 and 313, when the experiment was terminated. For the first 127 days of culture, the weight, percent weight increase, daily growth rate (DGR), specific growth rate (SGR), yield and feed conversion ratio (FCR) were significantly better in prawns reared in the Hapa compared to the B-nets. During the selective harvest phase the blue claw, orange claw and berried females were selectively harvested and the remaining prawns returned to the cages. After changes in stocking density through culling, ancova was used to compare the effect of mesh size with the total number of prawns returned to the cages as a covariate. Yield was significantly higher in the Hapa nets. Weight, DGR, SGR and FCR were also consistently higher in the Hapa nets, although not always significantly different. The overall better performance of prawns reared in the Hapa net cages was due to: (i) the reduction in the entry of predator and competitor species in the finer-meshed Hapa compared to the larger mesh B-net, (ii) more natural food trapped inside the Hapa cages, and (iii) a higher number of selectively harvested prawns, which decreased stocking density in the cages and improved growth. Use of small mesh size nets is recommended in the cage culture of M. rosenbergii in inland natural water bodies.
    • Article

      Netcage rearing of the Asian seabass Lates calcarifer (Bloch) in brackishwater pond: The technical and economic efficiency of using high protein diets in fingerling production 

      JA Madrones-Ladja & MR Catacutan - The Philippine Agricultural Scientist, 2012 - College of Agriculture, University of the Philippines Los Baños
      Intensification in the grow-out culture of high-value fish requires a large quantity of quality fingerlings. Fingerling production is a component of fish farming that comprises nursery and grow-out culture, and may be a commercial enterprise option for fish farmers with limited pond area. The nursery rearing of the Asian seabass Lates calcarifer (Bloch) was conducted in netcages inside a brackishwater pond. The fish were fed with two isocaloric, high-protein diets formulated at the Southeast Asian Fisheries Development Center (SEAFDEC/AQD) and a control treatment: diets A (40.40% crude protein, CP) and B (46.17% CP), and trashfish (TF) as control. Hatchery-bred seabass early juveniles of two size groups (S1, 4.0 ± 0.2 g; S2, 2.40 ± 0.03 g) were stocked at 75–100 fish per m3 and given diets A or B at 6–10% of average body weight (ABW) d-1, or TF at apparent satiation. Seabass given the formulated diets attained the desired size (≥ 20–40 g) after 45 d but not the fish fed with trashfish. Size and treatments showed significant effects on final ABW, although no significant interaction between these factors was shown to affect body weight. As expected, S1 fish attained a significantly higher ABW (30.7 ± 18 g) compared with S2 fish (20.7 ± 11 g) regardless of diet treatment. Seabass fed with trashfish exhibited significantly lower final ABW (6.6 ±1.6 g) than those fed Diet A (33.4 ± 6.5 g) or Diet B (37.1 ± 9.4 g). Fish size did not have any significant effect on specific growth rate (SGR), but diet treatments did. SGR was significantly better when either Diet A (5.2 ± 0.30) or B (5.4 ± 0.20) was used compared with the SGR of seabass fed with trashfish (1.7 ± 0.5). Although size and treatment did not show significant interaction on fish survival, the use of bigger seabass resulted in higher survival (89 ± 11%) compared with smaller seabass (80 ± 11%). Regardless of size, similar survival was attained in seabass fed Diet A (89 ± 6%) or B (95 ± 5%), significantly higher than that in seabass given trashfish (72 ± 6%). An interaction between size at stocking and diet treatment significantly affected protein efficiency ratio (PER). When S1 fish was used, diets A and B gave similar PER. However, when S2 fish was used, diet A gave significantly higher PER (2.49 ± 0.02) among the treatments (P < 0.05). Regardless of size, significant differences (P ≤ 0.05) were observed in the mean production cost, revenue and income among the three diet treatments. Moreover, post hoc analysis using Tukey’s HSD test further showed that use of diet B resulted in significantly higher revenue (PhP25,132.80) and income (PhP12,597.47) compared with the two other treatments. Trashfish treatment gave the least revenue (PhP 9,525.60) and negative income (- PhP 1,798.40). Production cost was not significantly different between diets A and B. Hence, diet B is the most economically viable and productive diet treatment. The low break-even price of fingerlings obtained for diet B showed that selling price can still be reduced to lower production cost in grow-out farming.
    • Article

      A new device for recording the feeding activity of milkfish 

      G Kawamura & AR Castillo Jr. - Nippon Suisan Gakkai Shi. Bulletin of the Japanese Society of Scientific Fisheries, 1981 - The Japanese Society of Scientific Fisheries
      Knowledge on the feeding activity is basic and very important for rearing fish. The information on the feeding activity rhythm of the animal suggests the proper time to feed it. Many devices have been designed to record the feeding activities of aquatic animals. Some are mechanical devices which are difficult to maintain in good conditions for a long time. None of the present devices can be applied to milk-fish because of its characteristic manner of taking food. In this paper, a new electrical device for recording the feeding activity of milkfish is reported.
    • Article

      New records of a marine macrobenthic algae of Panay and Guimaras Islands 

      MRJ Luhan, AQ Hurtado-Ponce, NC Guanzon & GC Trono - Philippine Journal of Science, 1992 - Science and Technology Information Institute
      Thirty new records of macrobenthic algae for Panay and Guimaras Islands are reported, consisting of 12 species of Chlorophyceae, 4 Phaeophyceae and 14 Rhodophyceae.
    • Article

      A new species of the sanguinea-group Quatrefages, 1866 (Annelida: Eunicidae: Marphysa) from the Philippines 

      CJ Glasby, MAE Mandario, I Burghardt, E Kupriyanova, LM Gunton & PA Hutchings - Zootaxa, 2019 - Magnolia Press
      A new species of the Marphysa sanguinea group, M. iloiloensis n. sp. (Annelida: Eunicida: Eunicidae), is described from the Marine Annelids Hatchery of the Southeast Asian Fisheries Development Center, Aquaculture Department (SEAFDEC- AQD), Iloilo Province, Philippines. It represents the first record of this group in the Philippines. The new species is most similar morphologically to M. hongkongensa Wang, Zhang & Qiu, 2018, but can be distinguished from it by having fewer branchial filaments, a pair of faint eyes (absent in M. hongkongensa), and in slight differences in jaw morphology and chaetation. The embryos of the new species develop inside a jelly cocoon attached to the entrance of the adult burrow; this is the first time that egg-containing cocoons have been found in any species of the sanguinea-group. Phylogenetic analysis based on the mitochondrial gene cytochrome c oxidase subunit I (COI) revealed that Marphysa iloiloensis n. sp. is genetically distinct from all other analysed Marphysa species and forms a sister group to M. hongkongensa. A revised identification key to members of the sanguinea-group in Southeast Asia is provided.
    • Article

      Nitrogen and phosphorus digestibility and excretion of different-sized groups of milkfish (Chanos chanos Forsskal) fed formulated and natural food-based diets 

      NS Sumagaysay-Chavoso - Aquaculture Research, 2003 - Blackwell Publishing
      This study determined the digestibility of nitrogen and phosphorus, and the excretion rate of different-sized groups of milkfish fed a commercial diet, a SEAFDEC formulated diet or lab-lab (natural food-based diet). Fish (31.2–263.0 g) were stocked in 12 units of 300-L fibreglass tanks filled with aerated seawater. The postprandial total ammonia-nitrogen (TAN) and phosphate (PO4-P) excretion of fish were estimated from changes in TAN and PO4-P concentrations in water for 24 h. Digestibility was determined from the nitrogen, phosphorus and Cr2O3 content of the diets, and pooled faeces after the fish had been fed diets marked with chromic oxide. TAN excretion rate (mg TAN kg−1 fish day−1) was significantly lowest (P < 0.05) in medium to very big fish fed the lab-lab diet (60.8–124.4) and highest in small and medium fish fed the SEAFDEC diet (333.3–331.6) and small fish fed the commercial diet (280.1). Regardless of size, fish fed lab-lab excreted (mg PO4-P kg−1 fish day−1) significantly lower PO4-P (36.2) but did not differ with fish fed the commercial diet (64.8). Excretion rates decreased exponentially as fish weight increased but positively increased with feed ration. Excretion pattern of milkfish revealed two peaks: the first peak occurred 6 h after feeding and the second peak at 18 h for TAN and 21 h for PO4-P, coinciding with the start of the daylight hours. TAN and PO4-P excretion accounted for 20.5–34.6% of total N consumed and 18.7–42.6% of P consumed respectively. Approximately 27.9–42.5% of N consumed and 47.2–58.5% of P consumed were lost as faeces. Total nutrient losses were lower using the lab-lab diet (0.31 g N and 0.14 g P kg−1 fish) compared with the formulated diets (0.47–0.48 g N and 0.17–0.19 g P kg−1 fish); the losses decreased per kg of fish as fish size increased. Results suggest that the diet and size of fish influence wastage of N and P to the environment with greater losses in small fish and when artificial diets are used. Such measurements will provide valuable information for the preparation of N and P budgets for milkfish in grow-out systems.
    • Article

      Nitrogen and phosphorus utilization in the cyanobacterium Microcystis aeruginosa isolated from Laguna de Bay, Philippines 

      SF Baldia, AD Evangelista, EV Aralar & AE Santiago - Journal of Applied Phycology, 2007 - Springer Verlag
      Phytoplankton supports fisheries and aquaculture production. Its vital role as food for aquatic animals, like mollusks, shrimp, and fish cannot be overemphasized. Because of its contribution as a food source for fish, the growth kinetics of Microcystis aeruginosa, a dominant cyanobacterium in the lake, was studied. The regular occurrence of M. aeruginosa is experienced during the months of May to July or from September to November in Laguna de Bay, the largest freshwater lake in the Philippines. M. aeruginosa was collected from Laguna de Bay, isolated, and established in axenic conditions. Data on the growth kinetic parameters for nitrate-nitrogen and phosphate-phosphorus utilization by M. aeruginosa gave the following values: half-saturation constant (Ks), 0.530 mg N. L−1 and 0.024 mg P. L−1 respectively; maximum growth rate (μmax), 0.671. d−1 and 0.668. d−1 respectively; maximum cell yield, 6.5 and 6.54 log, cells. ml−1 respectively; nutrient level for saturated growth yield, 8.71 mg N. L−1 and 0.22 mg P. L−1 respectively; and minimum cell quota (Q0), 2.82 pg N. cell−1 and 0.064 pg P. cell−1 respectively. The low Ks value and high maximum growth rate (μmax) for phosphorus by M. aeruginosa would suggest a high efficiency of phosphorus utilization. On the other hand, the high Ks value for nitrogen indicated a low rate of uptake for this nutrient.
    • Article

      Nitrogen stable isotopes reveal age-dependent dietary shift in the Japanese scallop Mizuhopecten yessoensis 

      FA Aya & I Kudo - Isotopes in Environmental and Health Studies, 2017 - Taylor & Francis
      Ontogenetic niche shifts in diet are a consequence of changes in body size or resource partitioning between age classes. To better resolve the feeding patterns of the Japanese scallop Mizuhopecten yessoensis, we examined the relative importance of age and size in the diet of this species using stable isotope ratios of carbon (δ13C) and nitrogen (δ15N) from 2006 to 2009. Contribution of food sources was quantified using an isotope mixing model by comparing the muscle tissue isotope ratios to those of suspended particulate organic matter (SPOM) and their zooplankton prey (e.g. micro- and meso-zooplankton). Unlike the δ13C values, which remained constant with age and size, muscle δ15N values were more positively correlated with age accounting for 69 % of variations than size with only 46 %. Increasing 15N values with age suggested that shifts in diet from SPOM to micro- and meso-zooplankton occurred during ontogeny in M. yessoensis. Results of the isotope mixing model indicated that SPOM contribution to scallop’s diet decreased from 68 to 8 % while those of zooplankton increased from 15 to 50 % with increasing age. This study concludes that age-related dietary shift explains the enrichment of 15N, as a result of predation on zooplankton by M. yessoensis.
    • Article

      Nodavirus infection in hatchery-reared orange-spotted grouper Epinephelus coioides: First record of viral nervous necrosis in the Philippines 

      Y Maeno, LD de la Peña & ER Cruz-Lacierda - Fish Pathology, 2002 - Japanese Society of Fish Pathology
      Mass mortality occurred in 34-day old larval orange-spotted grouper Epinephelus coioides reared at a hatchery in the Philippines with clinical signs such as anorexia and abnormal swimming behavior. Histopathology of moribund fish demonstrated marked vacuolation of the brain, spinal cord and retina. Cytopathic effects were observed in SSN-1 cells inoculated with the tissue filtrate of affected grouper. Electron microscopy revealed non-enveloped virus particles measuring 20 to 25 nm in diameter in the cytoplasm of degenerated SSN-1 cells. Piscine nodavirus (betanodavirus), the causative agent of viral nervous necrosis (VNN), was detected in the affected tissues and SSN-1 cells inoculated with the tissue filtrate of affected fish by RT-PCR. This is the first record of VNN in the Philippines.
    • Article

      Non-linearity in ecosystem services: temporal and spatial variability in coastal protection 

      EW Koch, EB Barbier, BR Silliman, DJ Reed, GME Perillo, SD Hacker, EF Granek, JH Primavera, N Muthiga, S Polasky, BS Halpern, CJ Kennedy, CV Kappel & E Wolanski - Frontiers in Ecology and the Environment, 2009 - Ecological Society of America
      Natural processes tend to vary over time and space, as well as between species. The ecosystem services these natural processes provide are therefore also highly variable. It is often assumed that ecosystem services are provided linearly (unvaryingly, at a steady rate), but natural processes are characterized by thresholds and limiting functions. In this paper, we describe the variability observed in wave attenuation provided by marshes, mangroves, seagrasses, and coral reefs and therefore also in coastal protection. We calculate the economic consequences of assuming coastal protection to be linear. We suggest that, in order to refine ecosystem-based management practices, it is essential that natural variability and cumulative effects be considered in the valuation of ecosystem services.
    • Article

      Note: larvae of decapod crustacea of the Philippines. II. Laboratory-hatched first zoea of box crab 

      H Motoh - The Philippine Agriculturist, 1976 - College of Agriculture and Central Experiment Station, University of the Philippines at Los Baños
      This is the first report in the world on the characters of the first zoea of Calappa philargius under laboratory conditions. The zoea has a rostral, a dorsal and a pair of lateral spines on the carapace. The average length of larvae from tip of rostral to tip of dorsal spine is 1.26 mm, width, including both lateral spines, 0.74 mm and that of distance between outer margins of eyes, 0.47 mm. There are a pair of lateral hooks on the second and third abdominal segments. There are four natatory hairs on the first and second maxillipeds. Spinal arrangements on the endopodites of the first and second maxillipeds from proximal to distal segment are 2-1-0-2-5 (or 4) and 1-1-4 (or 3), respectively. The number of inner setae on the telson is six (3+3).
    • Article

      Notes on Lagenidium from larvae of Penaeus monodon Fabricius. I. Isolation and culture in artificial media. 

      RQ Gacutan & MCL Baticados - Fisheries Research Journal of the Philippines, 1979 - Fisheries Research Society of the Philippines
      The fungus, tentatively identified as Lagenidium , which attacks the nauplii to postlarval stages of P. monodon , has recently been isolated and cultured from infected larvae under laboratory conditions, using several kinds of agars and broths. Growth of the colonies was found to be faster in the broths and in the Sabouraud agar ghan in the othr media. Observations were made on the variations in sizes of the vegetative and reproductive structures and on the manner of sporulation to form the basis of identification.
    • Article

      Notes on the completion of the life cycle of Penaeus japonicus in captivity in the Philippines 

      ET Quinitio, FD Parado-Estepa & E Coniza - Philippine Journal of Science, 1991 - Science and Technology Information Institute
      Penaeus japonicus nauplii from wild spawners were reared up to the early postlarval stage (PL20) in 12-t concrete tanks. A survival rate of 13-15% was obtained. Hatchery-reared postlarvae were restocked in concrete tanks for grow-out. After six months, survival rate was 49.3% with mean body weight of 20 g and carapace length of 21-33 mm. Ablated and unablated females were stocked together with males at 1:1 sex ratio in broodstock tanks. After three months, 11% of the ablated prawns spawned whereas 1.4% of unablated females spawned after five months. Nauplii from these spawnings were reared up to the adult stage thus completing the life cycle of J. japonicus in captivity.
    • Article

      Notes on the construction of 12 cu m ferrocement tank for prawn broodstock 

      RT Tolosa - Journal of Ferrocement, 1978 - International Ferrocement Information Center
      One of the important research studies at the Aquaculture Department of SEAFDEC is the maturation of Penaeus monodon females in captivity. Equal numbers of male and female prawns are stocked in tanks. Ovarian maturation is induced using the eyestalk ablation method.

      Initial successes in obtaining gravid female prawns by ablation in wooden and concrete tanks led to the attempt at mass production of spawners. This significant in view of the high cost of procuring prawn spawners from the wild and of their seasonal spawning.

      This paper is an offshoot of such an attempt. Its aim is to develop an economical, rational and easy method of constructing ferrocement tanks suitable for Penaeus monodon maturation.
    • Article

      Notes on the courtship and mating behavior in Penaeus monodon Fabricius (Decapoda, Natantia) 

      JH Primavera - Crustaceana, 1979 - Brill Academic Publishers
      Courtship and mating behavior in the sugpo or giant tiger prawn, Penaeus monodon Fabricius, are described. These are divided into three phases: parallel swimming of male and female; male turns ventral side up to female; and, male turns perpendicular to female, curves body around female and flicks both head and tail. Comparison with observations on P. japonicus and P. stylirostris is made.
    • Article

      Notes on the external sex characters of Chanos chanos (Forskal) spawners 

      H Chaudhuri, JV Juario, R Samson & LB Tiro - Fisheries Research Journal of the Philippines, 1976 - Fisheries Research Society of the Philippines
      In the present study, no visible differences between the sexes of C. chanos with reference to external features such as colouration, shape of head, snout and operculum, presence of tubercles or nasal pores, length, size and shape as well as any roughness in the various fins, could be found. However, the anal region of the mature milkfish (sabalo) exhibits discernible anatomical differences in the male and female. The male has two main openings visible externally: the anterior anus and the posterior urogenital opening at the tip of the urogenital papilla. The female has three main openings instead of two: the anteriormost anus, followed by the genital pore and the urinary pore located posterior to the genital pore at the tip of the urogenital papilla. Internal examinations were also made on both sexes. In ripe sabalo, it is easier to distinguish the sexes since milk oozes out of the urogenital pore by pressing the abdomen of the ripe male fish. Gravid females are identified by their distended abdomens.
    • Article

      Notes on the induced spawning, embryonic and larval development of the window-pane shell, Placuna placenta (Linnaeus, 1758), in the laboratory 

      JA Madrones-Ladja - Aquaculture, 1997 - Elsevier
      Intragonadal injection of 0.5 ml of a 2-mM serotonin solution or seawater irradiated by ultraviolet (UV) light (925–1395 mW h/l) induced spawning in male and female window-pane shell, Placuna placenta (Linnaeus, 1758). Generally, mature shells spawned 15–30 min after serotonin injection or 30–60 min after exposure to UV light-irradiated seawater. The average number of eggs released per female were 1.57 × 106 and 1.24 × 106, for serotonin and UV light-irradiated seawater, respectively. The method using UV light-irradiated seawater is simpler to perform than serotonin injection into the gonads and can be applied to both individual- and mass-spawning experiments. Spawned eggs averaged 56 ± 5 μm in diameter and fertilization was 100% successful. After fertilization, the polar body formed after 15 min and trochophores were observed actively moving in 325 min. Embryonic development was completed in less than 6 h. Straight-hinged veligers with mean shell length (SL) of 84 ± 18 μm appeared in the cultures 18–20 h after fertilization. Fed daily with microalgae Isoschrysis galbana (Parke), the larvae developed to early umbo on the second day of culture when SL was 103 ± 17 μm, while late-umbonal veligers of SL 145 ± 21 μm appeared on the seventh day. Crawling pediveligers were observed on day 9 when SL reached 205 ± 15 μm. Newly metamorphosed larvae appeared on the 14th day when SL of 238 ± 9 μm was reached. The survival rate at metamorphosis was 13%. The duration of the planktonic larval stages of P. placenta was about 14 d.