Effects Of Stocking Density And Feeding Rate On The Unit Yield Of Litopenaeus Vannamei And Analysis Of Culture Models

Litopenaeus vannamei is one of the three major cultured shrimps in the world.In 1988 Litopenaeus vannamei is introduced in China from Hawaii,and Litopenaeus vannamei’s large-scale cultivation began in 2000.The development of Litopenaeus vannamei aquaculture industry is lagging behind,due to the special geographical location,backward culture technology in Xinjiang.This situation restricted the promotion of Litopenaeus vannamei culture,so it was necessary to carry out related research on Litopenaeus vannamei culture technology.In this study,by setting different gradient stocking density and feeding rate,the effects of stocking density and feeding rate on Litopenaeus vannamei’s unit yield are studied by using the method of regression analysis in this paper,in order to explore the regularity of stocking density and feeding rate of Litopenaeus vannamei’s Pond Aquaculture in Northern Xinjiang.Principal component analysis method is used to analyze the influence of indicators on Litopenaeus vannamei’s culture efficiency,and the good Litopenaeus vannamei’s culture mode is selected.The main results of this paper are as follows:（1）In the experiment of the effect of stocking density on the unit yield of Litopenaeus vannamei,the results showed that:（1）The average unit yield increased slowly with the increase of stocking density,the average body size,average survival rate and average feed coefficient changed little.（2）The relationship between unit yield Y and stocking density SD showed a quadratic curve Y=-0.055SD²+12.111SD-78.096（R²=0.9702）.The curve shows a trend that the Litopenaeus vannamei’s unit yield increases slowly with the increase of stocking density,The theoretical inflection point of zero growth is（110,588.61）.The F-test showed that the curve equation extremely significantly reflects the trend of Litopenaeus vannamei per unit yield with the stocking density（F=43.283,n=6,F>F0.01）.（3）This curve not only significantly reflects Litopenaeus vannamei’s unit yield increases with the increase of stocking density in the range of 21-79 ind/m²stocking density,but also significantly predicts Litopenaeus vannamei’s unit yield may increase with the increase of stocking density outside the range of upper limit79ind/m²in this experiment.（2）In the experiment on the effect of feeding rate on unit yield of Litopenaeus vannamei,the results showed that:The relationship between average unit yield Y and daily feeding rate DFR is a quadratic curve,y=-35173DFR²+4455.2DFR+140.62（R²=0.8397）.With the increase of feeding rate,the average unit yield of Litopenaeus vannamei increases and slows down.The dotted line E-F section shows that the average yield per unit area increases slowly with the increase of feeding rate,and the theoretical inflection point of zero growth is F（0.063,281.7）.the inflection point of the curve equation shows that the theoretical maximum daily feeding rate of Litopenaeus vannamei in northern Xinjiang is 6.3%.The F-test showed that the curve equation significantly reflected the trend of the change in unit yield of Litopenaeus vannamei with the daily feeding rate(F=9.828,n=7,F>F_0.05).（3）Principal component analysis of Litopenaeus vannamei culture model showed that:（1）The cumulative contribution rates of principal component 1 and principal component 2 were 83.711%.（2）Yield and cost had higher load values on principal component 1,indicating that principal component 1mainly reflected economic indicators.Stocking density,feeding level and ammonia nitrogen had higher load values on principal component 2,indicating that principal component 2 was the main reaction technical index.（3）Comprehensive analysis of various indicators.According to different aquaculture modes,the order from good to bad in each aquaculture pond is B6>B7>B5>B2>B8>B4>B3>B1>B9.The culture mode of pond B6（water surface 3.800 hm²+stocking density 53 ind/m²+feeding rate 2.1%and unit yield 333.33 kg/667m²）is the best.The research results of this paper confirm that the yield of Litopenaeus vannamei shows a gradually increasing and slower change with the increase of stocking density,and its theoretical maximum stocking density is 110ind/m².With the increase of daily feeding rate,the per unit yield showed a gradually increasing and slower change,and its theoretical maximum daily feeding rate was 6.3%.The technical index load value in the culture of Litopenaeus vannamei is less than the economic index,but the technical index is the basis and key of the culture,and determines the success or failure of the culture.The above results and conclusions filled the blank of the culture technology of Litopenaeus vannamei in Xinjiang,and also provided a theoretical basis for the culture of Litopenaeus vannamei.