Now showing items 1-7 of 7

    • Article

      The effect of background color and rotifer density on rotifer intake, growth and survival of the grouper (Epinephelus suillus) larvae 

      MN Duray, CB Estudillo & LG Alpasan - Aquaculture, 1996 - Elsevier
      Rotifer intake and early growth and survival of Epinephelus suillus larvae were determined in terms of rotifer visibility against the background color of rearing tanks and density. The larvae were stocked at 30 l−1 in 200-l fiberglass tanks with phytoplankton (green water). Larvae were fed rotifers at densities of 5, 10 and 20 ml−1. Growth and survival were comparable among larvae in both tan and black tanks with green water. Rotifer intake was significantly higher in larvae in tan tanks. In black tanks, the survival of larvae at Day 14 was enhanced by the high rotifer density of 20 ml−1. Rotifer intake and growth of larvae were similar at all densities.
    • Article

      Growth and survival of milkfish (Chanos chanos), seabass (Lates calcarifer) and rabbitfish (Siganus guttatus) larvae reared at the same density in different sized tanks 

      CB Estudillo, MN Duray & ET Marasigan - The Israeli Journal of Aquaculture-Bamidgeh, 1998 - Society of Israeli Aquaculture and Marine Biotechnology
      Growth and survival of the larvae of milkfish (Chanos chanos), seabass (Lates calcarifer) and rabbitfish (Siganus guttatus) in 40, 200 and 500 liter rearing tanks were evaluated at day 14. Milkfish larvae survived better (46%) in 500 l than in 200 l (7%) tanks. All larvae died on day 6 in the 40 l tanks. Growth was better in the 200 l tanks than in the 500 l tanks. The survival rate of the seabass larvae was significantly different in the 40 l (47%), 200 l (61%) and 500 l (75%) tanks, but growth was highest in the 40 l tanks. Rabbitfish larvae had the highest survival in 500 l tanks (7%) but the same growth in all tank sizes.

      The optimum tank size may vary for different fish species. However, small containers are more convenient to use because they require less manpower, are easily manipulated and more cost- effective.
    • Article

      Improved hatchery rearing of mangrove red snapper, Lutjanus argentimaculatus, in large tanks with small rotifer (Brachionus plicatilis) and Artemia 

      MN Duray, LG Alpasan & CB Estudillo - The Israeli Journal of Aquaculture-Bamidgeh, 1996 - Society of Israeli Aquaculture and Marine Biotechnology
      A hatchery rearing scheme for the red snapper, Lutjanus argentimaculatus, is described. The feeding regime consisted of Chlorella, Brachionus, Artemia and minced fish. The average survival rate at day 24 was 27% in 3-ton tanks but only 3% in 0.5-ton tanks. From an initial length of 2.15 mm at stocking, larvae grew to 8.2 mm on day 24 and 30.6 mm on day 55. Growth and survival were best when larvae were fed screened Brachionus (<90 μm) during the first 14 days. Larvae fed Artemia at 1, 2 and 3 per ml per day weighed similarly on day 35 but were longer at the higher feeding levels and survived better at the lower levels. Larvae fed Artemia at 2 per ml had a higher survival when the ration was given four times a day rather than 1-2 times a day.
    • Article

      Larval rearing of the grouper Epinephelus suillus under laboratory conditions 

      MN Duray, CB Estudillo & LG Alpasan - Aquaculture, 1997 - Elsevier
      A protocol for rearing orange-spotted rockcod, Epinephelus suillus in the hatchery is described. The feeding regime consisted of Chlorella, Brachionus, Artemia and minced fish. With this regime, survival rates at Day 24 were 19.8% in 3-ton tanks and only 7.4% in 0.5-ton tanks. From an initial length of 1.62 mm on Day 0, larvae grew to 10.94 mm on Day 24 and 51.4–65.1 mm on Day 60. Larval growth and survival rate were improved when larvae were fed screened (less than 90 μm) Brachionus during the first 2 weeks. Survival was even better among larvae fed Brachionus until Day 35. Artemia, at a density of 3 ml−1, given once daily to larvae in 24 ppt seawater improved growth and survival.
    • Conference paper

      Optimum stocking density and tank size for larval rearing of the grouper, Epinephelus coioides 

      MN Duray, CB Estudillo & LG Alpasan - In The Fourth Asian Fisheries Forum: Proceedings of the Fourth Asian Fisheries Forum, Beijing, 16-20 October 1995, 1997 - Asian Fisheries Society
      The effect of stocking of stocking density and tank size on early growth and survival of grouper, Epinephelus coioides (=suillus) larvae were determined. In one experiment, larvae were stocked in 500L tanks at densities of 5, 10, 20 and 30 per liter and fed rotifers at 15 ind/mL. After 21 d, larvae attained best growth (9.6 mm) and highest survival (32.2%) at 20/L. In another experiment, larvae were stocked at 30/L in 40 L, 200 L and 500 L circular fiberglass tanks. Survival was highest in 500 L (22.3%) and lowest in 40 L tanks (0.5%), but larvae in 200 L tanks were larger (8.2 mm total length, 1.5 mg dry weight) on day 21. Thus in small tanks, 20 larvae/L is the optimum stocking density. In larger tanks of 500 L, 30 larvae/L is feasible.
    • Article

      Salinity tolerance of larvae of the mangrove red snapper (Lutjanus argentimaculatus) during ontogeny 

      CB Estudillo, MN Duray, ET Marasigan & AC Emata - Aquaculture, 2000 - Elsevier
      Salinity tolerance and the effects of salinity on growth, condition factor and chloride cell (CC) densities were evaluated for Lutjanus argentimaculatus larvae during ontogeny. Tolerance of L. argentimaculatus larvae to abrupt changes of salinity from 32 ppt varied with age. Periods to 50% mortality (LT50) were significantly (P<0.05) longer for 0-day-old larvae than for 7-, 14- and 21-day-old larvae. Tolerance of abrupt salinity change increased remarkably, starting on day 28. Although abrupt transfer to test salinities caused substantial mortalities, L. argentimaculatus larvae, regardless of age (0-, 7-, 14-day-old), showed significantly longer LT50 when abruptly transferred to 8 and 16 ppt than for transfers to 24 and 40 ppt (P<0.05). Growth of L. argentimaculatus larvae at 16, 24, 32 (control) and 40 ppt was not significantly different either at the end of the first rearing phase (days 0–21) or second phase of rearing (days 22–50). Survival was significantly lowest at 40 ppt (4.3%) at the end of first phase of rearing (P<0.05). There were no significant differences in survival rates at the end of the second phase of rearing; however, the condition factor (K) of larvae reared at lower salinities was significantly higher than that of fish at 40 ppt (P<0.05). Gill epithelia of 42- and 50-day-old larvae showed increasing density of CC with increasing salinity.
    • Article

      Transport of hatchery-reared and wild grouper larvae, Epinephelus sp. 

      CB Estudillo & MN Duray - Aquaculture, 2003 - Elsevier
      Optimum packing conditions for the transport of hatchery-reared and wild grouper larvae were investigated under simulated condition or actual air transport. Simulation of transport motion was done through the use of an electric orbit shaker to identify the best packing conditions for the transport of grouper larvae at various ages. Simulated transport was conducted in hatchery-reared grouper larvae at day 35 (mean TL=14.73 mm), 45 (mean TL=15.23 mm) and 60 (mean TL=28.16 mm) at packing densities of 50, 100 and 200 larvae l−1 and at high (28 °C) or low (23 °C) temperatures. Packing density of 50 larvae l−1 was best for 45- and 60-day-old larvae 8 h transport at low temperature. However, packing density could be increased to a maximum of 100 larvae l−1 8 h transport at 23 °C with mortality rates ranging from 2.3% to 5.3%. The increase in total NH3 level was dependent on temperature, packing density and size of larvae. High packing density (100–200 larvae l−1) and temperature (28 °C) resulted in increased NH3 level and mortality rates during transport. In addition, regardless of the temperature, NH3 levels were consistently higher for 60-day-old larvae. Day-60 grouper larvae displayed strong resistance to handling/mechanical stress compared to 35-day-old larvae probably because most are already fully metamorphosed at this stage. Based on these results, a packing density of 50 larvae l−1, a temperature of 23 °C and larval age of 60 days were considered as the best transport conditions for hatchery-reared grouper larvae. When these transport conditions were used in experiment 2, for 26-day-old hormone-metamorphosed, 60-day-old naturally metamorphosed or 60-day-old pre-metamorphosing hatchery-reared grouper larvae, a 100% survival rate was attained in all treatments. Seven days of hormone (T3) treatment did not accelerate metamorphosis of wild-caught transparent grouper larvae (tinies) significantly. Survival rates of hormone-treated transparent tinies (H-tinies), untreated black tinies (B-tinies) and untreated transparent tinies (T-tinies) were also similar after 8–9 h air transport (experiment 3). The results of the current study suggest that T3 treatment did not affect the performance of hatchery-reared and wild-caught transparent tinies/larvae during transport. In addition, mass mortalities of these transported tinies during the nursery phase were associated with nutritional aspect and the sudden confinement of these undomesticated wild-caught grouper to small space rather than transport or hormone treatment effects.