摘要
以枝角类为饵料,分两阶段研究了饵料密度对2～30日龄(Days after-hatching,DAH)南方鲶仔稚鱼生长、成活、残食的影响.前期阶段:2～6DAH仔鱼,分为未投饵组和投饵组,投饵组的饵料密度设为250、500、1000、2000个/L;后期阶段:7～30DAH稚鱼,饵料密度设为250、500、1000、2000、4000个/L.结果表明:前期阶段,250个/L饵料密度组仔鱼生长最快,终体重为0.055g;未投饵组的仔鱼残食十分严重,残食率高达60%;500个/L饵料密度组的仔鱼成活率最高,达95.56%.后期阶段,2000个/L饵料密度组稚鱼生长最快,终体重为1.57g;250、500个/L饵料密度组稚鱼的残食较为严重,当饵料密度增加至2000个/L时,残食率下降至10.00%,成活率达到83.33%.随饵料密度的增加,两试验阶段仔稚鱼的特定生长率(Special growth rate,SGR)均呈先增加后降低的趋势,全长变异系数呈下降趋势.综合生长和成活两项指标,2～6DAH仔鱼的适宜饵料密度为500个/L,7～30DAH稚鱼的适宜饵料密度为2000个/L.饵料不足引发的严重残食,是南方鲶苗种成活率低的重要原因.适宜的饵料密度能够有效地控制残食.
The effects of prey density on the growth,survival and cannibalism of Silurus meridionali larvae and juveniles were investigated.Cladocera was used as prey and the experiment was separated for the early-stage and late-stage larvae and juveniles.Non-feeding and feeding groups were divided for early-stage experiment.The catfi shes of 2～6 days after-hatching （DAH） were reared at densities of 250,500,1 000,2 000 individuals per liter,and those of 7～30 DAH at the densities of 250,500,1 000,2 000,4 000 individuals per liter.For the early-stage ones,the best growth with fi nal weight of 0.055 g at the density of 250 individuals per liter and the highest survival of 95.56% at that of 500 individuals per liter were obtained.The highest cannibalism rate （60%） was observed in the non-feeding group,which was significantly higher than the feeding group.For late-stage ones,the juveniles of 7～30 DAH fed at the density of 2 000 individuals per liter showed the best growth （fi nal weight：1.57 g）.Compared with the higher cannibalism at the densities of of 250 and 500 individuals per liter,the cannibalism dropped to 10%,and survival increased to 83.33% at that of 2 000 individuals per liter.Special growth rate （SGR） increased with the increasing of prey densities from low to optimum,then decreased above the optimum prey density,and the coefficient of variation （CV） in total length had a degradative trend varying with the increasing of prey densities at each experimental stage.Based on the analysis of growth and survival against prey density,the densities of 500 individuals per liter during 2～6 DAH and 2 000 individuals per liter during 7～30 DAH are proved the most optimum for culturing S.meridionali larvae and juveniles.The cannibalism was the main cause of mortality,which was positively correlated to density and could be controlled by prey density during the larval and juvenile periods.Fig 2,Tab 2,Ref 27
出处
《应用与环境生物学报》
CAS
CSCD
北大核心
2010年第2期235-239,共5页
Chinese Journal of Applied and Environmental Biology
基金
国家科技支撑计划项目(No.2007BAD37B02)
湖北省"十一五"重大科技攻关项目(No.2006AA203A01)资助~~
关键词
南方鲶
仔稚鱼
饵料密度
生长
成活
残食
Silurus meridionalis
larvae and juvenile
prey density
growth
survival
cannibalism
