Now showing items 1-7 of 7

    • Article

      Culturing seahorse (Hippocampus barbouri) in illuminated cages with supplementary Acetes feeding 

      LMB Garcia, GV Hilomen-Garcia & RLM Calibara - The Israeli Journal of Aquaculture-Bamidgeh, 2010 - The Society of Israeli Aquaculture and Marine Biotechnology (SIAMB)
      Juvenile Hippocampus barbouri were grown in illuminated cages with or without supplemental daytime feeding of thawed Acetes (a planktonic marine crustacean), or in non-illuminated cages with Acetes feeding, as a supplement to light-attracted zooplankton prey. After ten weeks, seahorses in illuminated cages fed Acetes had the highest mean body weight (2.24 g) and length (8.20 cm), but these did not significantly differ from seahorses in unfed illuminated cages (1.88 g; 7.25 cm), which did not significantly differ from those in fed non-illuminated cages (0.88 g; 6.32 cm). In all treatments, the mean instantaneous growth rate in body weight declined progressively throughout the test but the instantaneous growth rate in stretched length did not vary. Mean survival (76-100%) of seahorses in fed non-illuminated cages and in unfed illuminated cages did not vary significantly over the test period. The mean survival of seahorses in fed illuminated cages was lowest (54%), but did not significantly differ from the other treatments. Juvenile H. barbouri grown in illuminated cages had better growth than those in non-illuminated cages, but survival was reduced when seahorses in illuminated cages were fed Acetes.
    • Article

      Diet composition and feeding periodicity of the seahorse Hippocampus barbouri reared in illuminated sea cages 

      LMB Garcia, GV Hilomen-Garcia, FT Celino, TT Gonzales & RJ Maliao - Aquaculture, 2012 - Elsevier
      The zooplankton prey composition and feeding periodicity of juvenile and adult seahorses Hippocampus barbouri reared in illuminated and non-illuminated sea cages were compared. Mean frequency of occurrence (%FO), prey composition (%N), and gut fullness of seahorses were calculated from analyses of gut contents. Compared with juvenile seahorses, adults consumed more variety of prey consisting of copepods, larvae of decapods, polychaetes and fish, and euphausid shrimps. Calanoid copedods were found in the gut of more juvenile (%FO = 47) and adult (%FO = 64) seahorses in illuminated cages but harpacticoid copepods were ingested by more juvenile fish (%FO = 50) in non-illuminated cages. Decapod larvae (%N = 66) in illuminated cages dominated the diet of juvenile seahorses, whereas in non-illuminated cages harpacticoid copepods (%N = 59) did. Calanoid copepods and decapod larvae (%N = 91–97) comprised the bulk of ingested prey among adult seahorses in all experimental cages. The gut of caged seahorses was generally full during daytime but declined in the evening, becoming almost empty at midnight, particularly among juveniles. Cage illumination commencing at midnight increased the number of filled guts at dawn (0400 h) among juvenile and adult seahorses. Unlike adult seahorses over a 24-h period, the overall incidence of filled guts among juveniles was not different between those in non-illuminated and illuminated cages. These results provide an alternative to growing caged H. barbouri on cultured live food, particularly copepods attracted by night illumination.
    • Article

      Economic assessment of commercial hatchery production of milkfish (Chanos chanos Forsskal) fry 

      LMB Garcia, RF Agbayani, MN Duray, GV Hilomen-Garcia, AC Emata & CL Marte - Journal of Applied Ichthyology, 1999 - John Wiley and Sons
      The economic viabilities of two types of commercial hatchery milkfish (Chanos chanos) fry operations were assessed and compared. Based on the actual cost of input, the physical facilities, and the potential production yields, four commercial hatcheries previously used for shrimp (Penaeus monodon fry production were classified as either largeor smallscale operations. Cost-return analysis revealed high profits for both types of operation. The return on investment (54-61 %) and the payback period ( approximately 1.5 years) were comparable between the two types, although a large-scale operation (476 %) had double the working capital return of a small-scale hatchery (221 %). Benefit-cost analysis over a 5-year period also revealed positive and above-baseline discounted economic indicators [net current value = 0.2-2.2 million Philippine Pesos (1 US Dollar = 25 Philippine Pesos); internal rate of return = 88-107 %]. The net benefit-cost ratio of a large-scale operation (2.0) was higher than that of a small-scale hatchery (1.4), suggesting a slight edge in the investment viability of a large-scale hatchery. Compared with a large-scale operation, a small-scale hatchery was more sensitive to changes in the acquisition price of eggs or newly-hatched larvae and in the price of selling hatchery fry. Both types of operation are viable nonetheless when the acquisition cost is P6000 per million eggs or larvae and hatchery fry are sold at P0.50 each. Together, profit and investment in milkfish hatchery fry production appear viable, making milkfish an alternative commodity for production in many abandoned shrimp hatcheries. The limited availability of spawned eggs and larvae for rearing and the quality of hatchery fry are issues requiring urgent attention.
    • Article

      Feeding selectivity of the seahorse, Hippocampus kuda (Bleeker), juveniles under laboratory conditions 

      FT Celino, GV Hilomen-Garcia & AGC del Norte-Campos - Aquaculture Research, 2012 - Blackwell Publishing Ltd
      This study examined the feeding selectivity of Hippocampus kuda juveniles under captive conditions and evaluates different food organisms that could be used to improve hatchery-rearing of this species. Newly born H. kuda were reared for 10 days in 60-L capacity tanks and fed rotifers (Brachionus rotundiformis), zooplankton (mostly Pseudodiaptomus annandalei and Acartia tsuensis) alone or both food sources. The size and amount of food ingested increased as seahorses grew. Selective feeding of seahorses appeared to change as they develop, preferring copepod adults over nauplii and rotifers. A. tsuensis was highly selected by juveniles over P. annandalei. Specific growth rate in terms of body weight (SGR-BW, 15% day–1) was the highest and mortality rate (9% at day 10) the lowest in seahorses fed a mixed food sources. Slowest growth rate (0.3% day–1) and highest mortality rate (60% at day 7) were observed in seahorses fed rotifers alone. These results indicate that copepods are suitable food for seahorse juveniles, but a mixture of food organisms in the rearing tank environment enhances survivorship and growth of H. kuda, thus potentially providing a source of cultured rather than wild specimens for characterizing the life history of this threatened species.
    • Article

      Grow-out of juvenile seahorse Hippocampus kuda (Bleeker; Teleostei: Syngnathidae) in illuminated sea cages 

      LMB Garcia & GV Hilomen-Garcia - Aquaculture Research, 2009 - Blackwell Publishing
      This paper examines the feasibility of rearing 10–15-day- and 0.7–1.5-month-old seahorse Hippocampus kuda in illuminated sea cages to continue existing hatchery protocols to mass produce H. kuda for trade and enhance depleted wild stocks in their natural habitats. Thawed Acetes (a planktonic crustacean abundant in inshore seas) was fed to juvenile seahorses in lighted and unlighted sea cages while one group in lighted cages was not fed Acetes. After 10–12 weeks of rearing, both mean body weight and stretch height increased in all treatment groups, with lighted cage-reared seahorses fed Acetes being heavier (2 g) and longer (8 cm) than the other two treatment groups. Although instantaneous growth rates declined during the rearing period, these were generally higher among Acetes-fed seahorses in lighted cages (0.02–0.07) compared with those in the unlighted cages with Acetes and lighted cages without Acetes feeding. Mean survivorship in all groups ranged from 9% to 74% after the trials, but mean survivorship of juveniles in lighted cages with Acetes feeding (9–74%) was consistently lower than the two treatment groups as a likely result of crustacean and piscine predators being attracted by light and the odour of leftover Acetes in the lighted cages. These results demonstrate that light-attracted zooplankton prey supplemented by Acetes feeding may provide essential nutrients for the growth of H. kuda juveniles in illuminated sea cages. With further improvement in the grow-out protocol, it may provide a possible alternative livelihood to seahorse fishers and sufficient seed to re-populate depleted wild stocks of H. kuda.
    • Article

      Morphological abnormalities in hatchery-bred milkfish (Chanos chanos Forsskal) fry and juveniles 

      GV Hilomen-Garcia - Aquaculture, 1997 - Elsevier
      Morphological abnormality has been observed in hatchery-bred milkfish juveniles. To characterize and quantify the occurrence of these anomalies, hatchery-bred milkfish juveniles from commercial nursery ponds were sampled, and the development of abnormalities in tank-reared fry and juveniles was monitored. Small specimens were cleared and stained using a KOH-alizarin technique for osteological examination. The occurrence of gross abnormalities in hatchery-bred milkfish juveniles reared in commercial ponds was highly variable (3–26%). These abnormalities were predominantly a cleft on the branchiostegal membrane (CBM) and a deformed operculum (DOp), which was mostly folded. CBM was commonly associated with a deformity or the partial to total absence of its supporting branchiostegal rays (DABr). DOp and DABr, but not CBM, were first detected during the early juvenile stage. Reference samples of wild fry did not develop similar proportions of abnormalities when reared in tanks, indicating that these abnormalities are predetermined or induced before the fry stage. Slow growth and development were observed in fish with opercular and branchiostegal abnormalities. A high mortality rate (70%) of abnormal fish was also observed after handling and transfer of stock. These results demonstrate that morphological abnormalities such as CBM and DOp do not only affect the appearance of milkfish but also interfere with its growth and survival.
    • Article

      Sensitivity of fertilized milkfish (Chanos chanos Forsskal) eggs to mechanical shock and simulated transport 

      GV Hilomen-Garcia - Aquaculture, 1998 - Elsevier
      Naturally-spawned milkfish eggs are routinely subjected to physical manipulation during collection and transport. To avoid unnecessary mortalities, sensitivity of milkfish eggs to mechanical shock was determined at different times after fertilization. Shock sensitivity was assessed in terms of egg mortality within 8 h after a free fall over calibrated heights. The LD50 and LD10 (drop height resulting in 50% and 10% mortality) were estimated for 11 stages of embryonic development. The corresponding force (F) imparted to eggs on impact after a free fall was also computed. LD10 estimates (cm) and their corresponding F (erg per egg) showed that shock sensitivity of milkfish eggs was high during cleavage until the early segmentation stage, rapidly declined as segmentation proceeded until the head and tail started to separate from the yolk, but returned to high levels when the embryo begun twitching and the heart beating until near-hatching. To determine the sublethal effects of mechanical shock, C-shaped embryos were subjected to a free fall over varying heights and transported to a hatchery for further incubation and hatching. The effects of varying periods of simulated transport (mobile or stationary periods) were also examined. At C-shaped embryo stage, neither mechanical shock (F, 13–127 erg per egg) nor prolonged shaking (3–9 h) simulating mobile periods of egg transport affected hatching rate, larval mortality, and incidence of deformed larvae. Exposure to still water (unshaken) simulating stationary periods of egg transport, however, tended to lower hatching rate and significantly increased the incidence of deformed larvae and the combined mortalities and deformed larvae. These results indicate that the sensitivity of milkfish eggs to mechanical shock varies during incubation and that C-shaped embryos may be manipulated or transported with minimum risk of injury. Some recommendations are given regarding proper handling and transport of fertilized eggs.