摘要
20 0 0年 5月中、下旬对长江口南汇边滩泥螺种群进行了调查和统计分析 ,结果表明 :泥螺种群呈聚集型分布 ;泥螺种群密度分别为 2 1.2 /m2 和 32 .8/m2 ;生物量分别为 2 5.60g/m2 WW和4 4 .89g/m2 WW或 2 .0 5g/m2 DW和 3.4 9g/m2 DW ;平均壳高分别为 1.19cm和 1.34cm ,壳高日生长量为 98.7μm ,月生长率达 2 4 .9% ;种群分别以壳高 1.0 0～ 1.2 0cm ( 4 7.0 6% )和 1.2 0～ 1.4 0cm( 4 1.90 % )的种群占绝对优势 ;性成熟个体比例分别占 32 .4 %和 78.3% ,整个泥螺种群处于生长期向繁殖期过渡阶段。壳高 (H)与壳宽 (B)、湿重 (WW )、存水量 (F1)、相对存水量 (F2 )与WW之间回归方程分别为 :H =0 .180 4 3+1.2 750 B、WW =0 .4 4 75 H2 .512 8、F1=0 .760 2 WW -0 .4 661、F2 =34 .0 2 1 WW - 8.666,相关显著。平均肥满度 ( 0 )和鲜出肉率 (PF)分别为 2 99.2 7%和 62 .15% ,它们与 WW呈负相关 ,回归方程分别为 :0 =34 7.0 8- 38.11 WW和PF =10 5.74 -34 .72 WW ,前者相关性较差 ,后者显著。 2 0 0 0年 5月初泥螺旺发与水动力条件、营养盐累积及饵料密切相关 ;目前的人工捕捞水平不会导致泥螺资源种群的数量下降 ,反而有助于发挥泥螺种群的环境净化功能。
The \$Bullacta exarata\$ population in the Nanhui tidal flat of the south bank of the Yangtze Estuary were examined on May 13～14 and 27～28.The population was clump-distributed,but the contagiousness index was rather low.The density of the population was 21.2 and 32.8 individuals/m\+2 at two sampling dates,respectively,with the corresponding biomass being 25.6 and 44.89 g/m\+2 (wet weight) or 2.05 and 3.49 g/m\+2 (dry weight).The average shell length at two sampling dates was 1.19 and 1.34 cm,respectively.The daily growth of shell height and monthly growth rate were 98.7 μm and 24.9%,respectively.The snails with shell height ranging from 1.00～1.20 cm on May 14 and 1.20～1.40 cm on May 28 were the majotity in the population.Mature adults accounted for 32.4% and 78.3% individuals in the two sampling dates,respectively,indicating that the population was in a trasition period between growth and reproduction phases.The regression relationship between shell height(H) and shell width(B),between H and WW,between the rate and relative rate of water preservation (F1 and F2) and WW was:H=0.180 43+1.275 0*B,WW=0.447 5*H\+\{2.512 8\},F1=0.760 2*WW-0.466 1,F2= 34.021 *WW-8.666,respectively.The average obesity (O) and the percentage of fresh flesh (PF) are 299.27% and 62.15% with the regression equations being O=347.08-38.11*WW and PF=105.74-34.72*WW,respectively.The high population density of \$B.exarata\$ in May 2000 may be related closely with the hydrological conditions and the nutritional materials.The influence of the snail harvest was discussed in relation to the change of the snail population and its role in water purification.
出处
《长江流域资源与环境》
CAS
CSSCI
CSCD
北大核心
2001年第3期216-222,共7页
Resources and Environment in the Yangtze Basin
基金
河口海岸国家重点实验室1999年度开放基金
