Now showing items 1-20 of 1447

    • Article

      Pond culture of sugpo, P. monodon (Fabricius) 

      JH Primavera & FD Apud - The Philippine Journal of Fisheries, 1976 - BFAR
      A resume is presented of the practical considerations involved in establishing a sugpo pond culture operation, as a guide to fish farmers, extension workers and others interested in producing marketable sugpo in the Philippines. In addition to outlining the general biology of P.monodon , information is given for pond preparation, stocking, transfer from nursery pond to rearing pond, rearing, harvesting, processing and transport. A large appendix deals with the control of pests, predators and diseases, fertilisation and supplementary feeding, and incorporates an illustrated manual of operations.
    • Article

      Effect of different stocking densities on survival and growth of sugpo (Penaeus monodon Fabricius) in a milkfish-rearing pond 

      JH Primavera, FD Apud & C Usigan - Philippine Journal of Science, 1976 - STII-DOST
      Employing a direct stocking monoculture method, postlarval P. monodon were stocked in 8 compartments of a shallow milkfish rearing pond at densities of 1, 2, 3 and 4/sq m with replicates. Feeding was exclusively natural (microbenthic lablab and plankton); Chanos fingerlings were later introduced to control excessive growth of lablab. Measurements of temperature, DO, pH, salinity and alkalinity were taken daily; stock sampling of length and weight was done every 30 days. Halfway through the culture period, the nylon net separating the compartments was accidentally lifted thereby invalidating data for 5 of the compartments. The prawns were harvested after 5.5 months. Survival was approximately the same for all stocking rates (51.76% at 4/sq m; 50.20% at 2/sq m; 42.54% at 1/sq m and 49.75% for the five remaining compartments treated as one). Growth rates are less conclusive due to the paucity of data. Effects of such physiochemical conditions as high and shallow depth are discussed.
    • Article

      Survival rates of different Penaeus monodon Fabricius postlarval stages 

      JH Primavera - Philippine Journal of Science, 1976 - National Science Development Board
      Four different postlarval stages (P11, P15 , P21, and P25) of P. monodon were stocked in suspension nets at the rate of 200 fry/sq m with 3 nets for each postlarval stage. Pond bottom was simulated by filling each net with a 15 cm layer of mud; dried twigs were provided for protection of the fry. Feeding with lablab and determination of temperature, dissolved oxygen, pH, salinity and alkalinity were regularly undertaken. Results show higher survival rates for P15 and P18 compared to the other stages.
    • Article

      A simple method of tagging prawns 

      LM Rodriguez - Natural and Applied Science Bulletin, 1976 - University of the Philippines
      The recognition of individual animals is crucial to many aspects of research. Prawns present unique difficulties in this respect since they molt regularly. Thus almost all tagging and marking methods developed for prawns so far have proven inadequate. Some are lost during molting; others cause injury to the prawns. A new and efficient method has been developed at the Igang Sea Farming Station of the Aquaculture Department.

      Brass tags measuring 5 mm by 20 mm and numbered consecutively are encircled around the eyestalk like a small bracelet. The prawn is gently held at the base of the carapace by the left hand while the right hand slips the brass tag over the eye. The tag is gently pressed around the eyestalk to prevent its slipping out. All tagging is done under water to avoid stress.
    • 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

      Larvae of decapod crustacea of the Philippines - I. The zoeal stages of a swimming crab, Charybdis cruciata (Herbst) reared in the laboratory 

      H Motoh & AC Villaluz - Nippon Suisan Gakkai Shi. Bulletin Of The Japanese Society Of Scientific Fisheries, 1976 - The Japanese Society of Scientific Fisheries
      Six zoeal stages of Charybdis cruciata (Herbst) which are reared in the laboratory, are described. The zoea has a rostral, a dorsal and a pair of laterial spines. There are a pair of lateral hooks on the 2nd and 3rd abdominal segments. The number of natatory hairs on the rirst and second maxillipeds increased by one pair at each molt, being 4, 6, 8, 10, 12 and 14, in the 1st to 6th zoea, respectively. The number of inner setae on the telson are 3+3 in stage 1; 4+4 in stages 2 and 3, 4+1+4 in stage 4, and 5+5 in stages 5 and 6. Spinal arrangement form proximal to distal segment of the endopodite of the first maxillipeds are 2-2-0-2-5 in stages 1-3 and 2-2-1-2-6 in stages 4-6 and that of the second maxillipeds are 1-1-4 in stages 1 and 2 and 1-1-5 in stages 3-6.
    • 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

      The larval stages of benizuwai-gani, Chinoecetes japonicus Rathbun reared in the laboratory 

      H Motoh - Nippon Suisan Gakkai Shi. Bulletin Of The Japanese Society Of Scientific Fisheries, 1976 - The Japanese Society of Fisheries Science
      This study deals with the larval stages of C. japonicus, and with the comparison with those of Zuwaigani, C. opilio. There are 2 zoneae and 1 megalopa. The larval stages of C. japonicus are morphologically similar to those of C. opilio excepting some characters as follows: (1) Chromatophores of Zoeae and megalopa are vermillion or crimson in C. japonicus and brown or reddish in C. opilio. (2) C. japonicus is generally bigger than C. opilio in zoeae and megalopa. (3) Length of postero-lateral spine on 3rd abdominal segment is>1.3times the length of the 4th abdominal segment in C. japonicus, but is shorter than (rarely equal to) that in C. opilio. (4) Ischiopodite of cheliped has no spine in C. japonicus, but it has a spine in C. opilio, in megalopa.
    • Article

      Induction of maturity and spawning in Penaeus monodon Fabricius, 1798, by unilateral eyestalk ablation (Decapoda, Natantia) 

      RG Wear & AC Santiago Jr. - Crustaceana, 1976 - Brill Academic Publishers
      Preliminary experiments carried out at the Aquaculture Department of the Southeast Asian Fisheries Development Centre in the Philippines have achieved success in the rearing of viable F1 postlarvae of Penaeus monodon from pond reared stocks. Unilateral eyestalk ablation was carried out on 100 female. 7 of these had successfully spawned at 23-months. Egg numbers up to 355,000 per female and successful hatch rates of up to 81% wee obtained. Bilaterally ablated female suffered total mortality by 196 days from eyestalk removal without 1 recorded spawning. Similarly, no spawnings were obtained from unablated controls. It is difficult to determine whether success can be solely attributed to unilateral ablation, or whether a fortuitous choice of experimental site played some major role. In any case, the data obtained are a valuable guide for future work aimed at propagating P.monodon commercially under fully controlled conditions.
    • Conference paper

      A preliminary report on the fauna of decapod crustacea in the mangrove and estuarine areas of Batan Bay, Panay Island, Philippines 

      H Motoh & NB Solis - In Proceedings of the International Workshop on Mangrove and Estuarine Area Development for the Indo-Pacific Region, Manila, Philippines, 14-19 November 1977, 1977 - Los Baños, Laguna, Philippines: Philippine Council for Agricultural and Resources Research
      In the Philippines, the total mangrove site for aquaculture development and others is about 576,000 hectares which constitute only 1.9 percent of the country's land resources. There are at present about 176,000 hectares of fishponds, representing 30.5 percent of the total mangrove resources in the country.

      Located in the northern part of Panay Island, 11°40' latitude and 122°30' longitude, Batan Bay has approximately 2,500 hectares with the average water depth of less than 5 meters during low tide. This bay consists of Port Batan, Banga Baylet and numerous tidal creeks. More than 80 percent of the coastal line in the bay is surrounded by mangrove areas and the rest is rocky or coconut forest. Shrimp fishing is considered an important fishery in Batan Bay. The main objectives of this survey are: 1) To know the species, particularly edible ones, of decapod crustaceae found in the mangrove and estuarine areas; 2) To know their ecology and life history; and 3) To provide the biological data available for protection or preservation of the mangrove area.
    • Article

      Population biology of the Japanese little-neck clam, Tapes philippinarum, in Kaneohe Bay, Oahu, Hawaiian Islands 

      WG Yap - Pacific Science, 1977 - University of Hawaii Press
      The Japanese little-neck clam, Tapes philippinarum, an introduced species in Kaneohe Bay, Oahu, Hawaiian Islands, has a thriving population only in a U5-hectare mud flat after heavy fishing triggered depletion in six other beds within the bay. Monthly gonad examination of the clams suggested that spawning occurs at a low level throughout the year with a peak from January to February. This observation is corroborated by the appearance of new recruits in the monthly sample from April to June and by their presence at low levels at other times of the year. Size-specific fecundity, determined indirectly from differences in the length: dry weight relationships of ripe and spent clams, ranges from 432,000 eggs in a 20-mm clam, increasing exponentially to 1.35 x 106 eggs in a 40-mm clam.

      Estimates of the population of clams 11 mm and larger, which were 3.09 x 106 in 1970 and 3.4 x 106 in 1972, show a growth of 5 percent per year during the 2-year period; monthly quantitative sampling showed no evidence of population growth after 1972. A survivorship curve obtained from the monthly samples gave a total instantaneous mortality of z = 0.2005. The age-specific mortality agrees with the age-frequency of the empty shells collected from the bed, with a correlation coefficient of 0.9345 with 4 d.f. The condition of the empty shells indicated that 57 percent of the mortality is attributable to crab predation, mainly by Thalamita crenata, which constitutes 70 percent of the experimental crab catch in the clam bed. Sixty percent of the broken shells were 19.5 to 30.4 mm in length; in experiments with predation by T. crenata, 96 percent of those eaten fell within the 14.5 to 30.4 mm size range. The difference between the lower limits of the size ranges can be attributed to the size structure of the clams during the survey period. The experimental population had an artificially maintained size structure. Experimental exclusion of predators over a limited area suggested that crab predation regulates clam size structure but not clam density.
    • Article

      Decapsulation of Artemia cysts: A simple technique for the improvement of the use of brine shrimp in aquaculture 

      P Sorgeloos, E Bossuyt, EM Laviña, M Baeza-Mesa & G Persoone - Aquaculture, 1977 - Elsevier
      Although it is a common practice in different disciplines of fundamental research on the brine shrimp, and despite the very interesting applications that it offers for the use of Artemia in aquaculture, the "decapsulation" technique, which removes the outer layer of the cyst shell of Artemia, is not known to shrimp and fish aquaculturists.

      The present paper describes the technology developed by the authors for the routine decapsulation of Artemia cysts. The advantages which result from the use of decapsulated cysts in aquacultural hatcheries are discussed.
    • Article

      Effects of furanace on zoeae and mysis of Penaeus monodon. 

      RQ Gacutan & AT Llobrera - Kalikasan, The Philippine Journal of Biology, 1977 - University of the Philippines at Los Baños
      The toxicity of the chemotherapeutant Furanace on Z2 and M1 of the jumbo tiger prawn Penaeus monodon was assayed for a period of 24 hr. The LD50 for Z2 was 1.6 mg per liter; for M1, 2.0 mg per liter.
    • Article

      Variation in the vertebral number of the milkfish Chanos chanos, collected from various localities 

      T Senta & S Kumagai - Bulletin- Faculty of Fisheries Nagasaki University, 1977 - The Faculty of Fisheries, Nagasaki University
      A total of 2497 milkfish fry were collected in 1976 from nine localities in six countries, viz. India, Thailand, Indonesia, Philippines, Taiwan and Tahiti. Vertebra counts ranged from 40 to 45. The general trend of geographical gradient in vertebral counts in the milkfish was observed to be lower in the west (or otherwise, along continents) and higher in the east (or around oceanic islands). Extremes in the means of vertebral counts by localities were seen in the samples from India with 43.08 and from Tahiti with 43.82. It was suggested that there may be at least four subpopulations among the milkfish throughout the tropical Indo-Pacific waters.
    • Article

      Successful spawning of cultured Penaeus monodon Fabricius after eyestalk ablation 

      AC Santiago Jr. - Aquaculture, 1977 - Elsevier
      Preliminary experiments resulted in successful spawning of captive stock of the prawn Penaeus monodon, or “sugpo”, to complete the life cycle and produce a viable F1 generation of larvae. Gonadal development was induced using eyestalk ablation techniques on sexually mature females. Removal of one eyestalk was found to be sufficient to induce gonadal development, whereas bilateral ablation indirectly resulted in high mortality of the treated females. By comparison, successful spawning had not occurred in unablated animals after 9 months.

      Fry hatched from wild adult stock and reared to 25-day postlarvae were further impounded in brackishwater experimental ponds and reared for 4 months. A transfer of 1 500 animals were then made to marine pens. After a further 10 months, 600 animals were selected for the experiment; healthy females were ablated unilaterally and placed with 100 males for a further 9 months. Of the remaining 400 specimens, 200 were used as controls and the remainder ablated bilaterally, Seven of the 23-month old females with one eyestalk removed had spawned successfully by January 27, 1976.

      Egg numbers, hatching rate and larval survival compared favorably with data obtained from females of oceanic origin. It is not known if the success of the experiment was entirely due to the effect of ablation or to the choice of a suitable environment. Work is continuing to induce gonadal development under more closely controlled conditions to overcome the inadequate and unreliable supply of spawners.
    • Article

      Mass production in concrete tanks of sugpo Penaeus monodon Fabricius spawners by eyestalk ablation 

      JH Primavera, E Borlongan & RA Posadas - Fisheries Research Journal of the Philippines, 1978 - Fisheries Research Society of the Philippines
      Two batches of 196 and 181 P. monodon females were ablated on one eyestalk in March and July 1977, respectively, and a control batch of 180 unablated females was stocked in July 1977. The females were stocked with males in 120-ton concrete tanks with partial flowthrough of water and fed salted mussel (Modiolus metcalfei ) at 15% body weight daily. Total number of spawnings was 82 for the March-ablated group, 3 for the July-ablated group and 4 for the July unablated group. Maturation and mortality in relation to the moult cycle and tank plus water conditions are discussed.
    • Article

      Ovarian rematuration of ablated sugpo prawn Penaeus monodon Fabricius 

      JH Primavera & E Borlongan - Annales de biologie animale, biochimie, biophysique, 1978 - Institut National de la Recherche Agronomique
      Spent Penaeus monodon females were tagged around one eyestalk with numbered brass tags, stocked in a concrete tank with males, and periodically examined for ovarian rematuration over a six-month period (February to August, 1977). The females were either artificially-induced (ablated spawners from concrete tanks and marine pens) or wild spawners. Most of the wild spawners were ablated after spawning; some remained unablated to serve as controls. Out of a total of 349 experimental females, 35 or 10 1% had a second spawning and 5 or 1 4% a third spawning; none of the 74 controls spawned subsequently. The average number of days for maturation and rematuration were: ablation to first spawning, 22 6 days; first spawning to second spawning (for females ablated before the first spawning), 11 days; first spawning to second spawning (for females ablated after the first spawning), 15 days; and second spawning to third spawning, 10 4 days. Fecundity of rematured spawners is comparable to that of first spawners; there is insufficient data on hatching rate and fry survival.
    • Article

      Observations on artificial fertilization of eggs and embryonic and larval development of milkfish, Chanos chanos (Forskal) 

      H Chaudhuri, JV Juario, JH Primavera, R Samson & R Mateo - Aquaculture, 1978 - Elsevier
      Hydrated eggs obtained from a female milkfish, Chanos chanos, were artificially fertilized with the milt collected from a male injected with acetone-dried pituitaries of salmon. The fertilized eggs (1.1–1.25 mm in diameter) developed normally in seawater in basins and petri dishes at a salinity of 30–34‰, and successfully hatched in 25–28.5 hours at a temperature of 26.4–29.9°C. The yolk was completely absorbed in about 2.5 days and during this period many postlarvae died. A few larvae were reared up to 5 days but all died on the 6th day. Attempts were made to feed the postlarvae with freshly hatched trochophore larvae of oysters obtained from eggs artificially fertilized in the laboratory.
    • Article

      The lancelets [Cephalochordata, Amphioxi] of Lucena Anchorage, Quezon, Philippines 

      NC Carandang - Kalikasan: The Philippine Journal of Biology, 1978 - University of the Philippines at Los Baños
      Two species of lancelets (amphioxi) are described from Philippine waters: Branchiostoma belcheri and Epigonichthys cultellus. The characters suited for numerical evaluation in both species were examined statistically.

      Epigonichthys cultellus is reported for the first time from the Philippines. The specimens examined differ by the presence of a dark band behind the rostrum and anterior to the first myotome, the greater number of myotomes in the preatrioporal region, and the numerous sense papillae on the buccal cirri.
    • 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.