Now showing items 1-6 of 6

    • Conference paper

      Culture of tilapia in saline water 

      WG Yap - In Fishlink 2001, 29-31 May 2001, 2001 - University of the Philippines Aquaculture Society, Inc.
    • Oral presentation

      Growth and productivity of juvenile banana prawns, Penaeus merguiensis in natural and laboratory systems. 

      DJ Staples, DJ Vance & DS Heales - In Y Taki, JH Primavera & JA Llobrera (Eds.), Proceedings of the First International Conference on the Culture of Penaeid Prawns/Shrimps, 4-7 December 1984, Iloilo City, Philippines, 1985 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Growth and survival of Penaeus merguiensis juveniles were measured over four years in the Norman River estuary, south-eastern Gulf of Carpentaria. Growth in carapace length for the first 8-9 weeks after settlement was essentially linear and averaged 1.2 mm/week in summer at 29.5°C and 0.45 mm/week in winter at 19.5°C. A comparison of different cohorts under varying temperatures and salinities indicated that growth was temperature- but not salinity-dependent. Survival of newly settled postlarvae varied seasonally and was highest in spring (October-November).

      In the laboratory, a study of moulting rate and moult increment at 15, 20, 25, 30 and 35°C demonstrated that the optimal temperature for growth was 25-30°C. Survival of juveniles was also highest at intermediate temperatures. Effects of salinity and food ration amounts are discussed.
    • Oral presentation

      Larval growth and survival optima for four species of penaeids from Australia, as indicated by their distribution and abundance in the field. 

      PC Rothlisberg & CJ Jackson - In Y Taki, JH Primavera & JA Llobrera (Eds.), Proceedings of the First International Conference on the Culture of Penaeid Prawns/Shrimps, 4-7 December 1984, Iloilo City, Philippines, 1985 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Prawn catches from tropical northern Australia are dominated by four species of prawns: Penaeus merguiensis, P. semisulcatus, P. esculentus and P. latisulcatus. Three of the species (P. merguiensis, P. semisulcatus and P. latisulcatus) are widespread throughout the Indo-Pacific, while P. esculentus is endemic to northern and eastern Australia. The species appear, however, to have well defined and limited distribution on a smaller scale. Surveys of the larvae in the Gulf of Carpentaria, northern Australia, have shown both spatial and temporal heterogeneity in the abundance of all four of these species.

      Assessing the temperatures and salinities in which the larvae were caught may be a realistic indicator of conditions suitable for reproduction, as well as growth and survival of the larvae. Means of these distributions may be deemed optima and ranges indicate tolerances.

      Most of the larvae of all four species are found in water above 26°C and 31 ppt. However, the mean temperatures and salinities vary significantly between species. P. merguiensis has the lowest salinity optimum (31.8 ppt) and the highest temperature optimum (29.0°C). the other three species are similar for both temperature and salinity optima. P. latisulcatus has the lowest temperature optimum of 27.4°C compared with P. semisulcatus at 27.9°C and P. esculentus at 28.5°C. The salinity optima for these three species are almost indentical at approximately 33.2 ppt.

      While the ranges of temperatures of all four species are similar (21.5-30.6°C), the ranges of salinities in which the lar-vae are found coincide with the size of the biogeographic distribution of the species. The three widespread species have large salinity ranges: P. merguiensis, 26.2-34.9 ppt P. semisulcatus, 27.8-34.9 ppt: and P. latisulcatus, 28.6-34.9 ppt. The Australian endemic, P. esculentus, has the smallest and highest range, 30.1-34.6 ppt. This apparent inability of P. esculentus to tolerate low salinity water may restrict dispersal during the larval stages.
    • Conference paper

      Larval survival and megalopa production of Scylla sp. at different salinities 

      FD Parado-Estepa & ET Quinitio - In CP Keenan & A Blackshaw (Eds.), Mud Crab Aquaculture and Biology. Proceedings of an International Scientific Forum, 21-24 April 1997, Darwin, Australia, 1999 - Australian Centre for International Agricultural Research
      Salinity tolerance was determined for each zoeal stage of Scylla sp. Larvae from ablated pond-grown females were abruptly transferred to salinities of 12, 16, 20, 24, 28 and 32 ppt. Spawning salinity or previous rearing salinity was 32 ppt, except for Z5 which were previously reared at 26 ppt. The mean median lethal time or LT50 values were compared between salinities. For Z1 and Z2, highest values were obtained at 20–32 ppt. Z3 had highest LT50 values at 20–24 ppt and Z4 at 24–32 ppt. For Z5, highest LT50 values were obtained at 20–32 ppt. Another batch of Z3 and Z4 were subjected to the same abrupt salinity transfers and reared to the megalopa stage. Significantly higher percentages of larvae metamorphosed to the megalopa stage at salinities of 20–28 ppt when transfer to test salinities was at Z3. When transfer was at Z4 or Z5, the highest percentage of larvae moulted to the megalopa stage at 24–28 ppt or at 28 ppt, respectively.
    • Conference paper

      Role of growth hormone in the adaptation to sea water of juveline brown trout, (Salmo trutta) 

      JME Almendras & P Punet - In CL Marte, GF Quinitio & AC Emata (Eds.), Proceedings of the Seminar-Workshop on Breeding and Seed Production of Cultured Finfishes in the Philippines, Tigbauan, Iloilo, Philippines, 4-5 May 1993, 1996 - Aquaculture Department, Southeast Asian Fisheries Development Center
      The first part of the study investigates the ability of ovine growth hormone (oGH) to enhance the hypo-osmoregulatory and growth performance of juvenile brown trout after exposure to sea water (SW). Three groups of fish were either intraperitoneally implanted with cholesterol pellet (sham) or with a cholesterol pellet containing 250 µg oGH (treated) or not implanted (control). While still in fresh water (FW), gill Na+/K+ATPase activity of the oGH-treated group was four times higher than that of sham and control groups. Exposure to SW resulted to dramatic increases in plasma electrolyte levels of the sham and control groups, whereas the oGH-treated group showed only minor perturbations in plasma electrolyte concentrations. Further increases in gill Na+/K+ ATPase activity were observed in the oGH-treated group after SW exposure, while in the sham and control, a lag time of seven days was needed before gill ATPase activity started to increase. Additionally, by the end of the experiment, oGH-treated fish were significantly larger than non-treated ones.

      The second part of the study examines the time course of changes in plasma GH levels and GH free binding sites and affinity of the organs involved in osmoregulation in juvenile brown trout kept in FW or exposed to SW. Plasma GH levels increased significantly one day after SW exposure, reaching a peak on the 14th day. Concomitantly, GH free binding sites in the gills and liver decreased significantly in trout exposed to SW but remained unchanged in trout kept in FW. Reduction in GH free binding sites in SW-exposed trout indicates occupation of the gill and liver GH receptor by GH during the course of SW adaptation which may point to a direct role of GH on gill and liver physiology during hypo-osmoregulation.

      The second part of the study examines the time course of changes in plasma GH levels and GH free binding sites and affinity of the organs involved in osmoregulation in juvenile brown trout kept in FW or exposed to SW. Plasma GH levels increased significantly one day after SW exposure, reaching a peak on the 14th day. Concomitantly, GH free binding sites in the gills and liver decreased significantly in trout exposed to SW but remained unchanged in trout kept in FW. Reduction in GH free binding sites in SW-exposed trout indicates occupation of the gill and liver GH receptor by GH during the course of SW adaptation which may point to a direct role of GH on gill and liver physiology during hypo-osmoregulation.
    • Conference paper

      Tilapia, carp and catfish 

      ZU Basiao - In F Lacanilao, RM Coloso & GF Quinitio (Eds.), Seminar-Workshop on Aquaculture Development in Southeast Asia and Prospects for Seafarming and Searanching; 19-23 August 1991; Iloilo City, Philippines., 1994 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Research activities on tilapia focused on Oreochromis niloticus and red tilapia. Experiments include developing new experimental and statistical procedures for strain evaluation, development of a stable reference strain, development of a high-yield red tilapia strain through introgressive hybridization, comparison of fish growth in different environments relevant to aquaculture, development of an index for routine monitoring of salinity tolerance of existing tilapia strains/experimental stocks, evaluation of nutritional requirements of red tilapia, and determination of heavy metal contents of tilapia in Laguna de Bay, Luzon, Philippines. Research on carp (Aristichthys nobilis) and catfish (Clarias macrocephalus) were focused on improvement of methods for induced spawning, development of seed production techniques, and nutritional requirement of bighead carp fry and broodstock.

      Research on carp (Aristichthys nobilis) and catfish (Clarias macrocephalus) were focused on improvement of methods for induced spawning, development of seed production techniques, and nutritional requirement of bighead carp fry and broodstock.