培育密度及饵料种类对大竹蛏幼虫生长、存活及变态的影响

在水温为22.0~24.8℃、盐度为31~33、pH为8.10~8.50的条件下,研究了培育密度及饵料种类对大竹蛏Solen grandis幼虫生长、存活及变态的影响。结果表明：不同培育密度（5、10、20、40、80个/mL）下,幼虫的生长速度、存活率随着密度的增大而降低;40、80个/mL试验组幼虫不能发育至匍匐幼虫,即不能完成变态;5、10、20个/mL试验组幼虫的变态率随着密度的增大而减小,各阶段幼虫的发育时间随着培育密度的增大而延长。不同的饵料种类及投喂方式,即单独投喂（小球藻、塔胞藻、新月菱形藻、金藻、海洋红酵母）与混合投喂（金藻＋塔胞藻＋新月菱形藻）对幼虫的生长速度、存活率、变态率及幼虫各阶段发育时间的影响也不同,前期单独投喂金藻效果较好,以后混合投喂效果比较理想。研究结果表明,在大竹蛏苗种生产过程中,培育密度为10个/mL左右较为合理,且混合投喂比单独投喂效果更好。

Effects of stocking density and alga species on larval growth,survival and metamorphosis in bamboo clam Solen grandis

The impact of stocking density and alga species on larval growth,survival and metamorphosis in bamboo clam Solen grandis was investigated at water temperature of 22.0-24.8 ℃,a salinity of 31-33,and pH 8.10-8.50.The larval growth rate and survival were found to decrease with increase in stocking density（5,10,20,40,and 80 ind./mL）,no postlarvae being observed at 40 ind./mL and 80 ind./mL.The metamorphic rate was reduced with stocking density rising（5,10,and 20 ind./mL）,with longer developmental period.The better larval growth,survival,metamorphosis and shorter development period were observed in the bamboo clam fed only Chlorella saccharophila（Q）,Pyramimonas sp.（T）,Nitzschia closterium（X）,Isochrysis zhanjianggenesis（J）,or yeast（H） in the early rearing period.In the later rearing period,however,the clam fed the mixture of J,T,and X had better larval growth,survival,metamorphosis and shorter development period.The higher bamboo clam juvenile yield was found when the juveniles were fed the mixture of the algae at stocking density of 10 ind./mL in a hatchery.