饵料种类、规格、投喂量和养殖密度对脉红螺存活及生长的影响

Effects of Diet Species,Size,Weight and Stocking Density on Survival and Growth of Rock Shell Rapana venosa

在水温16~21℃下,将10个体质量(8.48±0.37)g的脉红螺Rapana venosa放于室外池塘中40 cm×30 cm×15 cm鲍养殖笼中,分别投喂壳长5.50~7.51 cm的栉孔扇贝Chlamys farreri、壳长(4.62±0.47)cm的紫贻贝Mytilus edulis和二种贝类等质量混合的饵料各480 g;在投喂量试验中,分别投喂240 g、480 g和700 g栉孔扇贝;饵料大小选择实验中,分别投喂480 g小个体、大个体和大小个体等质量混合的栉孔扇贝。在养殖密度试验中,分别投入5个脉红螺,折合2355.56 g/m^(3);10个,折合4711.11 g/m^(3);20个,折合9422.22 g/m^(3)。三组均投喂480 g栉孔扇贝,每组4个重复,饲养30 d,研究饵料种类、规格、投喂量和养殖密度对脉红螺生长及存活的影响。结果表明,各组间脉红螺成活率差异不显著(P>0.05);栉孔扇贝与紫贻贝混合投喂组脉红螺生长及获益显著较高(P<0.05),紫贻贝饵料系数显著较高(P<0.05);投喂大小混合规格的饵料脉红螺特定生长率、增重率和摄食率最高,但与小规格饵料组无显著差异(P>0.05);单笼投喂量700 g组,脉红螺摄食率显著高于其他两组(P<0.05);脉红螺养殖密度4711.11 g/m^(3)组饵料系数达到(2.70±0.35),显著高于其他两组(P<0.05)。以上结果表明,脉红螺是一种适宜投喂混合种类及混合规格饵料、需饵量大、耐高密度养殖的经济螺类。

Ten individuals of rock shell Rapana venosa with body weight of(8.48±0.37)g were reared in a 40 cm×30 cm×15 cm abalone breeding cage disposed in an outdoor pond,and fed Farrer’s scallop Chlamys farreri with shell length of 5.50~7.51 cm,blue mussel Mytilus edulis with shell length of(4.62±0.47)cm and two species of shellfish mixture at equal ratio at amount of 480 g per cage at water temperature of 16~21℃;in feeding quantity test,240 g,480 g and 700 g Farrer’s scallop were fed;in the diet size selection test,480 g of small individuals,large individuals and mixture of large and small Farrer’s scallop were fed,respectively;in the culture density of rock shell test,5 rock shell,equivalent to 2,355.56 g/m^(3);10 rock shell,equivalent to 4,711.11 g/m^(3);and 20 rock shell,equivalent to 9,422.22 g/m^(3) were reared in the cages,and all three groups were fed 480 g Farrer’s scallop.Each group had 4 replicates;the rock shell were reared for 30 days to probe into the effects of diet types,size,feeding amounts and stocking density on the growth and survival of rock shell.The results showed that there was significant better growth and economic benefits in the group fed the mixture of Farrer’s scallop and blue mussel(P<0.05),significant higher diet conversion efficient in the group fed blue mussel(P<0.05),without significant effect on survival rate of rock shell among each groups(P>0.05).The maximal specific growth rate,weigh growth rate and diet intake were observed in the group fed mixed size diets,without significant differences compared with the group fed small size diets(P>0.05).The rock shell fed 700 g diet per cage had significant higher diet intake in the groups(P<0.05).There was diet conversion efficient of(2.70±0.35)in the rock shell in 4,711.11 g/m^(3) group,significant higher than that in the other two groups(P<0.05).The findings suggest that rock shell is an economic snail which was suitable for mixed species and mixed size diets,and required high feeding level and high stocking density.