The Studies On High Density Cultivation Technology Optimization Of Danphniopsis Tibetana Sars

Daphniopsis tibetana Sars is a cladocera in low-medium saline lake. D. tibetana can be anutrition enrichment and high quality food for the marine larvae fishes, shrimps and crabs, andcan overcome the application limitation for Moina mongolica culture in northern seawater. Inorder to supply a kind of new live animal food for the marine larvae fishes, shrimps and crabs,studies on the optimization of culture conditions and population ecology of D. tibetana and therational use of D. tibetana has great theoretical and practical significance.This study intends to explore the optimization culture mode of D. tibetana, the mainresearch results are as follows:1. The population compensatory growth effect of D. tibetana following starvation.In this study, we evaluated how1d,3d,5d,7d,9d and11d of continuous starvation and0.5d,1d,1.5d and2d of intermittent starvation affected the population compensatory growtheffect of D. tibetana. After2-month experimental period, we found that starvation timesignificantly influenced population growth parameters, body length and the heart rate. Based onthese results, we suggest that1d of continuous starvation and0.5d of intermittent starvation areoptimal conditions for culturing D. tibetana, the age at first reproduction, intrinsic rate ofincrease(rm), reproduction frequency and average life span were16.3d,16.3d;0.136±0.003d-1,0.133±0.005d-1;426.3±8.04ind.,412.3±11.06ind.;54.5±1.60d,54.3±1.47d,respectively,significantly higher than others, body length and the heart rate were2.521mm,184/min, respectively, theresults indicated that D. tibetana had completely compensatory growth phenomenon; while3d,5d of continuous starvation and1d of intermittent starvation, rmwere0.118d-1,0.117d-1and0.077d-1, the population were still able to maintain growth, thereby, which had partiallycompensatory growth capacity, while the population had no compensatory capacity over7d ofcontinuous starvation and1.5d of intermittent starvation.2. The population dynamics and production of D.tibetana in large-scale culture condition.In this study, process parameters of the large-scale culture of D. tibetana in diluteseawater(S=18～20) had been conducted. Including the initial stock density, pure oxygen anddaily harvesting ratio. The results showed that initial stock density had a major influence onpopulation growth and daily production(P<0.05), under the different stock density culturecondition(200,550,900,1250ind./L), the highest density of D. tibetana population was9500±550.73ind./L in33d when the initial density was1250ind./L and the average dailyproduction was125.00±8.35g·m-3·d-1; comparison of pure oxygen and air, filling with pureoxygen could significantly improved the population density and daily production（P<0.05）, thehighest density of D. tibetana population was11600±560.45ind./L and the average daily production was156.82±8.49g·m-3·d-1when the initial stock density was1250ind./L; The dailyharvesting ratio significantly influenced population growth and daily production（P<0.05）andthe optimum harvesting ratio was at20%when the initial stock density was1250ind./L, thehighest density of D. tibetana population was12900±995.04ind./L and the average dailyproduction was176.52±15.08g·m-3·d-1.3. The effect of environmental factors on the induction and germination of D. tibetanaresting eggsEffects of the initial density (0.1,0.3,0.6,1.0and1.5ind./ml), variable temperature and sexration(day16,12,8℃,night8,6,4℃and sex ration6:0,5:1,4:2,3:3) on D. tibetana were studied,the result showed that the number of resting eggs were higher than the others when the initialdensity was0.6ind./ml, the reproduction of resting eggs and male of D. tibetana with thecooling had significant infuence, the number of the resting eggs were most and qualities werebest.The effect of germination rate of resting eggs on D. tibetana under salinity, photoperiod,temperature, preservation method were studieds, the results showed that the salinity ranged from8to20, the germination rate was declined with salinity increased,the optimum salinity was from12to16; the light was a necessary condition for the germination of resting eggs and which werenot germinated in dark, the highest germination rate was50%at12L:12D and which increasedwith temperature from12to20℃, the optimum temperature was20℃, C.muelleri was optimumfood for germination, the germination rate of resting eggs at-20℃were higher than at-4℃andshorten the germination time.