Now showing items 1-3 of 3

    • Conference paper

      Egg quality of grouper Epinephelus coioides fed different fatty acid sources 

      GF Quinitio, RM Coloso, NB Caberoy, JD Toledo & DM Reyes Jr. - 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
      Quality of eggs spawned by Epinephelus coioides fed fish by catch (control). Cod liver oil-enriched fish by catch (TFC), and commercial HUFA A-enriched fish by catch (TFS) was monitored. Monthly egg production, spawning frequency, fertilization rate, egg viability, and hatching rates of the control were significantly higher compared to TFS Egg production. Spawning frequency and hatching rate of TC and TFS were not significantly different. Results suggest that varying the species of fish by catch could provide the requirements of E. Coioides broodstock so as to provide quality eggs.
    • Article

      Induction of sex change in female Epinephelus coioides by social control. 

      GF Quinitio, NB Caberoy & DM Reyes Jr. - The Israeli Journal of Aquaculture-Bamidgeh, 1997 - Society of Israeli Aquaculture and Marine Biotechnology
      Mature female groupers (Epinephelus coioides) of different sizes were stocked in three floating net cages (2 fishes each) and in tanks (2-4 fishes) to induce sex change in the bigger female grouper after isolation from the original group. All the bigger fish (initial body weight 5.0-6.1 kg) in the floating net cages changed into males by the end of the experiment, while the smaller ones (initial body weight 4.5-5.2 kg) remained female. The fastest sex change was in cage 1 where the bigger fish had atretic oocytes one month after stocking and was milting after four months. In the other cages, milt production in the bigger fish was observed 6-10 months after stocking. In the tank-reared groupers, the biggest fish (initial body weight 6.4 kg) in the tank with four fishes was found to be milting about two months after stocking while the smaller fishes (initial body weight 3.4-4.0 kg) were still females. The fishes started to spawn two months later. In another tank that was stocked with two females, no sex change was observed in the bigger fish even 16 months after stocking. These results indicate that female groupers can be sexually changed into male by social control at the shortest period of four months in floating net cages and two months in tanks. However, there may be cases wherein sex change will not occur.
    • Article

      Sensitivity of grouper Epinephelus coioides eggs to handling stress at different stages of embryonic development 

      NB Caberoy & GF Quinitio - The Israeli Journal of Aquaculture-Bamidgeh, 1998 - Society of Israeli Aquaculture and Marine Biotechnology
      The sensitivity of grouper Epinephelus coioides eggs to handling stress at different stages of embryonic development was investigated. Naturally-spawned grouper eggs in floating net cages were collected and handled at the early cleavage, blastula, gastrula, neurula, and eyed stages. Egg viability, hatching rate and percentage of normal larvae were significantly higher (p<0.05) in eggs collected and stocked at the eyed stage than in all other stages. An increasing sensitivity to handling stress was observed in eggs from early cleavage to gastrula, as manifested by the decreasing percentage of viable eggs, hatched, and normal larvae. Sensitivity to handling stress decreased when development reached the neurula and eyed stages. Hatched larvae from eggs handled during the blastula and gastrula stages had high mortalities during the first 3-24 hours after stocking. The results of this study show that grouper E. coioides eggs are most sensitive to handling stress during the early cleavage to gastrula phases. The results imply that harvesting or collection of grouper eggs is best done after neurulation, when the embryo has already formed optic vesicles (eyed stage), to increase egg viability and the hatching rate. It will also minimize mortalities and the occurence of abnormal larvae.