Now showing items 1-7 of 7

    • Article

      Density dependent growth of the tropical abalone Haliotis asinina in cage culture 

      EC Capinpin Jr., JD Toledo, VC Encena II & M Doi - Aquaculture, 1999 - Elsevier
      The effects of different stocking densities on the growth, feed conversion ratio and survival of two size groups of the tropical abalone Haliotis asinina were determined. Three culture trials were conducted in net cages installed in a sheltered cove, Guimaras Province, Philippines. Trials 1 and 2 were conducted using 15–20 mm abalone juveniles for 150 days, while trial 3 was conducted using 35–40 mm abalone for 180 days. The animals were fed sufficient amounts of the red alga, Gracilariopsis bailinae (=G. heteroclada), throughout the experiment. There was an inverse relationship between growth (length and weight) and stocking density. Feed conversion ratio was not influenced by density, but was observed to be higher for larger animals. Survival was not significantly affected by density. Net cages are appropriate for culture of H. asinina. This study showed that H. asinina can reach commercial size of about 60 mm in one year. It also showed that growth of H. asinina can be sustained on a single-species diet. An economic analysis will be important in choosing the best stocking density for commercial production.
    • 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

      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.
    • Article

      Preliminary studies on the rearing of the red-spotted grouper, Epinephelus coioides larvae using copepod nauplii as initial food. 

      JD Toledo, SN Golez, M Doi, RS Bravo & S Hara - UPV Journal of Natural Sciences, 1996 - University of the Philippines in the Visayas
      One day old red-spotted grouper (Epinephelus coioides) larvae from SEAFDEC, Iloilo, were packed at 3.300 ind/L and transported to Dagupan, Pangasinan for larval rearing. Transport time was about 10 hours. More than 90% of the larvae were active after transport. These were reared in two 7-on tanks (Tanks 1 and 2) using Acartia nauplii and rotifers as a initial food and in one 10-ton tank (Tank 3) provided with rotifers only. Feeding incidence at the onset of feeding (Day 3) was higher (90-95%) in Tanks 1 and 2 than in tank 3 (85%). All larvae sampled from days 4 – 10 in Tanks 1 and 2 had food in the gut while feeding incidence in Tank 3 was variable (75-100%). Larvae in Tanks 1 and 2 showed consistently higher food electivity for Acartia nauplii than rotifers. Higher survival rates were observed in Day 13 in tanks provided with copepod nauplii (16-18%) than with the rotifers only (2%). Average total length on Day 13 was higher in copepod-fed larvae (4.5 ± 0.5 mm) than larvae fed with rotifers only (3.0 ± 0.3mm). All larvae fed with rotifers alone died on Day 15. A total of 675 larvae were harvested on Day 45 from Tanks 1 and 2. These results indicate the feasibility of transporting one day old E. coioides larvae for at least 10 h and of using copepod nauplii as food for the first feeding E. coioides larvae.
    • Article

      Seasonal availability of calanoid copepods (genus Acartia) in eastern Thailand using a light trap, as food organisms for marine fish larval rearing 

      A Ohno, T Singhagraiwan & M Doi - Asian Fisheries Science, 1996 - Asian Fisheries Society
      Zooplankton collected by the torch lighting method were investigated in a tropical coastal seawater pond in eastern Thailand. Copepods of the genus Acartia, such as A. sinjiensis, A. erythaea and A. pacifica, were predominant among the zooplankton collected. A. sinjiensis occurred almost throughout the year with a prolonged peak season from August to April. The highest abundance of adult A. sinjiensis aggregated under the light reached 35,700 individuals•l-1. The occurrence of A. erythaea and A. pacifica was intermittent with a short-term peak from March to April, during which their abundance was higher than A. sinjeinsis. The combination of water temperature and salinity was suggested to affect or regulate the biomass of these Acartia species. Among the Acartia species, A. sinjiensis seems to be the most important as a food organism available for marine fish larval rearing in eastern Thailand.
    • 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.
    • Conference paper

      Viability of milkfish eggs and larvae after simulated and actual transport 

      JD Toledo, M Doi & M Duray - In D MacKinlay & M Eldridge (Eds.), The Fish Egg: Its Biology and Culture Symposium Proceedings. International Congress on the Biology of Fishes, 14-18 July 1996, San Francisco State University, 1996 - American Fisheries Society, Physiology Section
      The viability of milkfish eggs and larvae after simulated and actual transport was investigated. Naturally-spawned milkfish eggs were collected and subjected to simulated or actual transport at early cleavage stage (stage 1), blastula (stage 2), gastrula (stage 3), "eyed" (stage 4), or newly-hatched larvae (stage 5). Replicate samples in aerated plastic jars served as controls. Mean hatching and survival rates and the percentage of newly-hatched larvae were significantly affected by the modes of transport and by the stage of embryonic development at transport. Eggs transported at the 'eyed' stage had higher viability compared to those transported at cleavage, blastula, or gastrula stages. There was no significant difference in the mean survival rate of the larvae after 26 days of rearing. However, the percentage of 45 day old larvae with apparent morphological abnormalities was lower in groups transported at stages 4 and 5. These observations indicate that milkfish eggs should be handled and transported during the late embryonic stages to minimize mortalities and the incidence of abnormalities in larvae.