| The larval rearing of Epinephelus coioide in this paper was conducted by timely and quantitatively adding shrimp-slices and effective microbes into the ponds, and those microbes can breakdown the shrimp slices, excreta, residues of animal and plant in the water. In the ponds, we could also find the existence of plankton, which ate microbe; Adding rotifers and copepods can use microbe and single cell algae; The groupers can use rotifers and copepods an so on. During the rearing period, it was significant to test the sun illumination, water temperature, its salinity, pH, ammonia nitrogen, nitrate nitrogen, nitrite nitrogen, labile phosphorus, total phosphorus and so on. These factors were essential, and especially their change attached great importance to the rearing of them. The measurement of plankton and their food ability on bacteria, and rearing ability towards phytoplankton, and the larval food and growth upon them was of equal important during the rearing period. The results suggested that:1. The change and factors of the feeding affected the physical and chemical factors in the water. In rearing periods, the water temperature shall be within the range of 26.2-30.2℃,salinity of 31-32,sunlight of 208-4540lux,DO of 6.86-7.99 mg/L. The pH was gradually lowing down, as the onwarding of the rearing period, and finally stabilized. At the same time, its pH was within the range of 7.43-8.08.As rearing went on, the content of NH3-N,NO2-N,NO3-N would increase accordingly, and three of them had the similar trending in their change. The nitrogen in the water was the main source for the shrimp slices, bait remains and excrements. The changing range of tri-nitrogen was NH3-N,0.07-1.83 mg/L,NO3-N,0.6-4.9 mg/L,NO2-N,and 0.005-0.576 mg/L, the highest value of non-ionic ammonia was 0.10mg/L, no poisoned sign for the larva; the content of (PO43-) and total phosphorus increased as the rearing went on. The (PO43-) was within the range of 0.04-1.15 mg/L,total phosphorus 0.28-1.59 mg/L. During the process, the shrimp slices and Effective Microorganisms had great influence upon the factors of the water. The former were split up into organic acid by the latter, which reduced the pH in the water. The content of tri-nitrogen and total phosphorus increased. Meanwhile, the EM accelerated the decomposing process of the shrimp slices, remains and excrement, which reduced the pH. Through the speeding up in the transformation from ammonia nitrogen to nitrate was to reduce the content. Due to the reason that, the microbe used nitrate to reduce nitrate nitrogen, while the EM could effectively reduced the labile phosphorus in the water, but finally failed to reduce total phosphorus. Hereby, discuss the shrimps slices and the EM that maintain the water's quality in a relatively stable way as a mechanism.2. Adopted the methodology of original positioning experimental ecolo-gism, to study the phenomenon of the larva on their bacterial productivity. The fact betrayed that during this period, the three elements increased their volume as the time went by. The same time of sampling, and different handling of G1, G2, G3 had different averaged volumes, namely,491.64μgC·dm-3,809.72μgC·dm-3,1200.14μgC·dm-3, that was G1 |
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