The Physiological And Ecological Study On Innocuous Breeding Technique Development Of Epinephelus Malabaricus

The thesis studies the physiology and ecology of Epinephelus malabaricus in a series of small water condition examinations. In the studies of the optimal salinity , the optimal temperature of the farming water , the optimal feeding rate and the optimal content of protein in the artificial diet and additive of enzyme of Epinephelus malabaricus, the writer has made some research on the optimize mode of its innocuous breeding technique, summarized the result of the small water condition examinations. Then a medium dimension experiment was carried out. Adopting an artificially ecological breeding mode without changing water, we carried out the experiment in artificial marine water. In such a water the farmed creature could form an ecological balance with the phytoplankton,zooplankton and decomposed microbe in the button, so even in a high stocking density condition, we need not change water and use medication while the water still had a crude immune effect that never deteriorated. In small water condition examinations, we studied the optimal temperature of the farming water of Epinephelus malabaricus by setting five temperature scalars: 24℃,26℃,28℃,30℃and 32℃. The result indicated that at the feeding rate of 2%, the Epinephelus malabaricus grows fastest when temperature is 28℃. In the study on the optimal salinity of the farming water we set four scalars : 3‰,5‰,9‰and 15‰.The result showed that when the salinity is 9‰the Epinephelus malabaricus grows fastest. By setting four feeding rates of 2%,2.5%,3% and 3.5%, we got the result that the optimal feeding rate is 3%. Studying the optimal content of protein in the artificial diet, we set four amounts of protein. They were 48.23%,51.43%,54.09% and 56.22%. The result showed the most preferable content of protein is about 51.43%. To improve the artificial diet, we added some phytase and adjusted the fish meal and vegetal feedstuff content. There came the result that when the vegetal feedstuff content in artificial diet is 25%～38%, we get the best breeding effect by adding phytase. Finally we carried out a medium dimension experiment in two indoor concrete ponds whose areas were both 28M2. We bred 1100 fish in each pond( averaged length was 5cm,middleweight is 4.2g in one pond and in the other pond the average length was 3cm,middleweight was 1.6g ) with a stocking density of about 40 fish per square meter. After breeding for 4 months, the Epinephelus malabaricuses in the two ponds grew to a specification of 20cm long and weighed 120g on an average in the first pond. Those in the second pond averaged 19 cm long and 110g. The survival rates are 74.81% and 64.91%. The coefficients of feeding are 0.784 and 0.729. Studies of the basic physiology and ecology of Epinephelus malabaricus in this thesis have been rarely reported. The medium dimension experiment has gained a constructive effect. The result of the study has not only filled up this learning domain, but also has an active direction in the rearing of Epinephelus malabaricus and commercial fish farming.