盐度和饵料密度对栉孔扇贝稚贝滤水率的影响

Effects of salinities and microalgae densities on filtration rates of scallop Chlamys farreri spats

采用静水法研究了恒定温度(24±0.5℃)、饵料密度(3.0×104cell/ml)、不同盐度(20、25、30和35)和恒定温度(24℃±0.5℃)、盐度30、不同饵料密度梯度(3.0×104、4.5×104和6.0×104cell/ml)对栉孔扇贝稚贝(壳长1.177～2.017mm)滤水率的影响。结果表明,栉孔扇贝稚贝的滤水率(FRS)开始随着盐度的升高而升高,在25～30之间存在最大值,然后随盐度的升高而下降,与盐度(S)间的相关关系为FRS=-30.893S2+1691.5S-19610(r=0.847,以整体干重计算)或FRS=-0.022S2+1.2236S-14.522(r=0.928,以个体数量计),通过公式推算在盐度27.8时FRS达到最大值,为3.54L/g.dw.h(2.49×10-3L/h.ind);投饵密度(Q)对栉孔扇贝稚贝的滤水率(FRQ)有显著影响(P<0.05),二者之间的相关关系为FRQ=-0.0693Q2+0.6484Q-1.0835(r=0.722),其变化趋势亦呈现先升高后下降的抛物线趋势,推算金藻密度为4.7×104cell/ml时滤水率最大,为0.43×10-3L/h.ind。

At temperature 24±0.5 ℃, the filtration rates of scallop Chlamys farreri spats （1. 177-2. 017 mm in shell length） were determined at different salinities （20,25,30,35） when microalgae density was 3.0 × 10^4 cell/ml and different density of microalgae （Dicrateria zhanjiangensis） （3.0 × 10^4 cell/ml, 4.5 × 10^4 cell/ml, 6.0 × 10^ 4cell/ml） when salinity was 30, using static water method. The relationship between the filtration rate （ FRs ） and the salinity （S） can be expressed by FRs=-30.893S^2＋1 691.5S-196 10 （r=0.847） （calculated by whole dry weight）, FRs=-0. 022S^2＋1. 223 6S-14. 522 （ r= 0. 928, calculated by individual quantity） . We estimated that at the salinity of 27.8, the filtration rate reached the maximum value, 3.54L/g ·dw · h（2.49 × 10^-3 L/ h · ind）. The filtration rate of the scallop spats increased with the salinity when the salinity was lower than 27.8 and decreased when it was more than 27.8. Feeding rate had significant influence on the filtration rates of the scallop （P〈 0.05）. When fed with D. zhanjiang ensis at in the concentrations of 3.0× 10^4 cell/ml, 4.5 ×10^4 cell/ml, 6.0 ×10^4 cell/ml, the filtration rate of the scallop spats increased and then decreased in a parabolic trend. It was estimated that the highest filtration rate（0.43 × 10^-3 L/ h · ind） could be reached when the density was 4.7 × 10^4 cell/ml. The relationship between the filtration rate （FRQ） and the microalgae density （Q） was FRQ=-0. 069 3Q^2＋0. 648 4Q-1. 083 5（r = 0. 722）.