光裸星虫与不同密度皱肋文蛤混养的生产性能及经济效益分析

Production performance and economic benefits analysis on mixed culture of Sipunculus nudus and Meretrix lyrata with different stocking densities

为提高光裸星虫(Sipunculus nudus)养殖的生产性能和经济效益,进行了光裸星虫与不同密度皱肋文蛤(Meretrix lyrata)的混养生产试验。试验以相同密度(25 ind/m^(2))的光裸星虫与不同密度的皱肋文蛤进行混养,皱肋文蛤的密度分别为150 ind/m^(2)(S1组)、200 ind/m^(2)(S2组)和250 ind/m^(2)(S3组),对照组为单养光裸星虫(C组,25 ind/m^(2))。结果显示,养殖300 d后,各组间光裸星虫和皱肋文蛤的存活率均无显著差异(P>0.05)。随着混养皱肋文蛤密度的增加,光裸星虫的终末体质量、增重率均呈下降趋势,其中S3组光裸星虫的终末体质量最小,增重率最低,分别比C组低了19.26%和22.24%。不同养殖密度对皱肋文蛤的终末壳长、终末体质量、增重率影响显著,其中S1组皱肋文蛤的终末壳长显著高于S3组(P<0.05),但与S2组差异不显著(P>0.05);S1组文蛤终末体质量、增重率显著高于S2组、S3组(P<0.05),其中S3组的终末体质量最小,增重率最低,分别比S1组低了28.99%和39.19%。随着皱肋文蛤放养密度的增加,光裸星虫的产量和产值均呈下降的趋势,而皱肋文蛤的产量和产值均呈先升后降的趋势,其中S1组经济效益最佳,比单养光裸星虫的对照组提高了35.88%。结果表明,光裸星虫与皱肋文蛤混养效益高于光裸星虫单养,但混养密度过高会导致产品规格小、毛利率和产出投入比降低。以毛利为评价指标,经多元回归分析显示,皱肋文蛤的最佳混养密度为157 ind/m^(2)。

This study was aimed to explore the production performance and economic efficiency of the mixed culture of Sipunculus nudus(25 ind/m^(2))and Meretrix lyrate with different stocking densities,i.e.,0 ind/m^(2)(the control),150 ind/m^(2)(group S1),200 ind/m^(2)(group S2)and 250 ind/m^(2)(group S3).The results showed that there was no significant difference in the survival rate of S.nudus and M.lyrate among the groups after 300 days of culture(P>0.05).The final body weight(FBW)and weight gain rate(WGR)of S.nudus decreased with stocking density increasing of M.lyrate and the lowest values were observed in group S3,which were 19.26%and 22.24%lower than the control group,respectively.Increasing density also had a significantly negative effect on growth parameters of M.lyrate,and the final shell length(FSL),FBW and WGR of M.lyrate in group S1 were 9.10%,28.99%and 39.19%higher than that in group S3 with significant differences(P<0.05).The yield and output of S.nudus showed a decreasing trend with stocking density increasing of M.lyrate,while the yield and output of M.lyrate showed a trend of increasing and then decreasing,among which the S1 group had the best economic benefits and was 35.88%higher than the control group.The mixed culture of two species obtained higher economic efficiencies than that of S.nudus alone,but too high density would lead to small animal size,lower gross profit rate and output-input ratio.Using gross profit as the evaluation index,multiple regression analysis showed that the optimal stocking density of M.lyrate was 157 ind/m^(2).