Now showing items 1-5 of 5

    • Article

      Food selection of early grouper, Epinephelus coioides, larvae reared by the semi-intensive method 

      JD Toledo, SN Golez, M Doi & A Ohno - Suisan Zoshoku, 1997 - Japan Aquaculture Society
      The grouper, Epinephelus coioides, larvae were reared in outdoor tanks with nauplii of copepods and/or rotifers, Brachionus rotundiformis as food. Nauplii propagated in tanks consisted mainly of Pseudodiaptomus annandalei and Acartia tsuensis. Gut content was examined for a total of 953 larvae sampled from day 3 to day 10 (day of hatching being day 0) . Grouper larvae successfully started feeding on early stage nauplii even if their abundance was as low as ca. 100 ind./l and showed better survival and growth thereafter compared to those fed with rotifers only. Feeding incidence reached 100% on day 4 when nauplii were available and only on day 9 when rotifers were given alone. Selective feeding ability of larvae seemed to start from day 4 and the larvae thereafter preferred to feed on medium- and large-size nauplii than rotifers. Coastal calanoid copepods of the genera Pseudodiaptomus and Acartia could be reproduced in tanks and their nauplii can be used as food for marine fish larval rearing.
    • Article

      Population dynamics of the calanoid copepod, Acartia tsuensis in a brackish-water pond in the Philippines 

      MSN Golez, A Ohno, JD Toledo, Y Tanaka & T Ishimaru - Fisheries Science, 2002 - The Japanese Society of Fisheries Science
      The occurrence pattern and population dynamics of Acartia tsuensis were investigated in a brackish-water pond in Panay Island in central Philippines by implementing both bi-monthly and daily sampling schemes. A. tsuensis occurred in the pond during the dry season (November-April) when the salinity of the water is in the range of 14 ~ 40 ppt but was completely absent at lower salinities. An almost constant rate of development from the nauplius 2 through to copepodite 5 stages of A. tsuensis was observed both in the pond and in the laboratory. The generation time ranged from 5.9~11.3 days. Fecundity had a positive linear corelation with chlorophyll a. Salinity and chlorophyll a affect the stage duration, mortality, and fecundity of A. tsuensis in the pond.
    • Article

      Preliminary investigation of feeding performance of larvae of early red-spotted grouper, Epinephelus coioides, reared with mixed zooplankton 

      M Doi, JD Toledo, MSN Golez, M de los Santos & A Ohno - Hydrobiologia, 1997 - Springer Verlag
      Larvae of red-spotted grouper, Epinephelus coioides, were reared in outdoor tanks with nauplii of copepods (mainly Pseudodiaptomus annandalei and Acartia tsuensis) and/or rotifers, Brachionus rotundiformis. Grouper larvae successfully started feeding on early stage nauplii even though their abundance was as low as approximately 100 individuals l-1 and showed better survival and growth thereafter compared to those fed with rotifers only. Incidence of feeding reached 100% on day 4 when nauplii were available and only on day 9 when rotifers were given alone. Larvae seemed to be poor feeders at the onset of feeding, attempting to capture any food organisms in the tank water. Selective feeding ability of larvae started from day 4 and the larvae then preferred to feed on medium- and large-size nauplii rather than on rotifers as they grew. Larvae appeared to have a better chance at surviving in the presence of early stage nauplii, which were probably caught more easily than rotifers.
    • Book chapter

      Studies on the use of copepods in the semi-intensive seed production of grouper Epinephelus coioides 

      JD Toledo, MS Golez & A Ohno - In CS Lee, PJ O'Bryen & NH Marcus (Eds.), Copepods in Aquaculture, 2005 - Blackwell Publishing
      Previous studies by the authors have shown the feasibility of using copepods in the semi-intensive seed production of grouper Epinephelus coioides. Early-stage E. coioides larvae preferred to ingest copepod nauplii over rotifers, although their abundance is relatively low. Higher growth and survival were obtained in larvae provided with copepods than larvae fed with rotifers alone. In this study, the authors tested various fertilization techniques for the mass production of zooplankton in ponds. The zooplankton population increased from an initial density of 86–148 ind/L to 1,524–3,186 ind/L 9–12 days after flooding. Major zooplankton were identified as rotifers, copepods, including cyclopoid and harpacticoid spp., and cladocerans. The calanoid copepod Acartia tsuensis can be propagated in 1-ton tanks in mixed species of microalgae alone or in combination with baker’s yeast. Density of A. tsuensis increased from 60 ind/L at stocking to about 900 ind/L 3–5 days thereafter. A prototype collector for copepod eggs and nauplii was tested. The average daily numbers of eggs and nauplii collected varied (2,300–117,600), depending on the density of copepodids and adults in the holding container (1,000–8,000 ind/10-L container). Hatching rates of collected eggs ranged from 34 to 89%. Collected eggs may be stored at low temperature (4–10°C) for up to 7 days. Duration and viability of eggs stored at low temperature were highly affected by the presence of protozoans. A. tsuensis eggs survived freezing to –20°C (0.3–1.7%) only at the cleavage stage, suggesting the feasibility of cryopreservation. Use of pond grown zooplankton, particularly the calanoid copepods, for the seed production of grouper is discussed.
    • Article

      Use of copepod nauplii during early feeding stage of grouper Epinephelus coioides 

      JD Toledo, MS Golez, M Doi & A Ohno - Fisheries Science, 1999 - Japanese Society of Fisheries Science
      Newly-hatched Epinephelus coioides larvae were stocked in five 5-ton tanks at an initial density of 25, 000 ind/tank. Copepod nauplii were propagated in four of these tanks by inoculating various densities (20 to 80 ind/l) of mixed copepodids of Acartia tsuensis, Pseudodiaptomus spp., and Oithona sp. three days before stocking larvae. Rotifers were added in these tanks on Day 7 at an initial density of 5, 000 ind/l. Larvae in the remaining tank were fed rotifers (only) starting Day 2 at 5, 000 ind/l. The feeding incidence, gut content, growth, and survival of larvae were better in tanks with higher density of copepodids (60-80 ind/l). These indices were lowest in larvae given rotifers only. Total n-3 HUFA of copepods was 2 to 3 times higher than rotifers. High percentages of 22:6n-3 (DHA) were detected in the fatty acid composition of Pseudodiaptomus (13%) and Acartia (24%) with DHA/EPA (20:5n-3) values of 1.4 and 2.6, respectively. By providing nauplii of copepods at the early feeding stage, an average survival of 3.4% at harvest (Day 36) was obtained in a pilot scale grouper seed production trial in three 10-ton tanks.