Effect Of Sand Sediment And Shelfters On Behavior, Growth And Survivorship Of Portunus Trituberculatus

Present study is designed to determine the effects of Sand, Shelters on circadian lurking frequencies and survival rate of Portunus trituberculatus, together with an analysis of the economic benefit involved. The primary results of these studies are listed below.1. Effect of different grain size sand on the lurking frequencies of Portunus trituberculatusThe parameters of circadian lurking frequencies and percent of lurking in daytime and night of juvenile Portunus trituberculatus with the body weight of 28.0±2.8g was investigated. The results showed that, There was a pronounced lurking peak displayed at about between 6:00 to 16:00 of the small crab, while there was a pronounced lurking valley displayed at about between 20:00 to 4:00. The lurking frequencies were highest at grain-size of 0.250～0.500mm group, which was 77.92%. The ratio of circadian lurking was highest at grain-size of 0.250～0.500mm group, which was 73.70%. but 18.23% at grain-size of 1.000～2.000mm group. These research results would provide theoretic basis for reconstrucing sand substrate of crab pond2. Effect of different shelter on the survival rate and economic benefit of Portunus trituberculatus cultured.The 90-day growth trial was conducted with three shelter treatments, which was glass reinforced plastics, plastic net and both of them, to investigate the effect on survival rate of Portunus trituberculatus, together with an analysis of the economic benefit involved. The results shows that, the survival rate in treatment groups was 13.00%, 12.50%,and 12.50%, respectively, which was higher than that of 8.25% in control groups significantly (p﹤0.05). Analysis of the economic benefit shows that, economic benefit was significantly (p﹤0.05) by different shelters, the highest was found at glass reinforced plastics group, which was 1500yuan.mu-1.3. Effect of different configuration of shelters on the survival rate and economic benefit of Portunus trituberculatus cultured.The 110-day growth trial was conducted to investigate the effect of the different configuration of shelters,together with an analysis of the economic benefit involved. The angle between two piece of glass reinforced plastics was 30°, 60°, 90°, 120°, and the angle between glass reinforced plastics and pond bottom was 30°,60°,90°. The results shows that, survival rate was affected significantly(p﹤0.05) by the configuration of shelters. Survival rate was highest at 30°,60°,90°group which angle was configurated with two piece of glass reinforced plastics. Survival rate was 12.67% , 12.83% , 14.50%. Analysis of the economic benefit shows that, economic benefit was affected significantly (p﹤0.05) by different configuratine of shelters,economic benefit was highest at 90°group which angle was configurated with two piece of glass reinforced plastics. It's 4600 yuan.mu-1.4. The earthen pond culture of the crab Portunus trituberculatus with the shelterAn application study of the shelter on production of Portunus trituberculatus, and analyse of economic benefit was performanced. The result shows that, survival rate was affected by shelters. Analysis of the economic benefit shows that, economic benefit was affected by different shelters, economic benefit was highest at a glass reinforced plastics pond, which was 6000yuan.mu-1.