【摘要】 1990年4—7月,在武汉东湖运用围圈的方法,研究了鲢(Hypophthalmichthys molitriac)、鳙(Aristichthys nobilis)对浮游动物群落结构的影响。观察表明:在鲢鳙混养的围圈中,原生动物和小型轮虫的数量较多,而甲壳动物和大型轮虫较少。在无鱼的围圈中,结果正好相反。就浮游动物平均生物量而论,无鱼的两个围圈(55.035mg/L和38.374mg/L)比鲢鳙混养的两个围圈(3.028mg/L和3.490mg/L)高得多。甲壳动物(无节幼体除外)的体长频度分布表明:在无鱼的围圈中,大型甲壳动物的频度比有鱼的围圈高得多。围圈实验表明:鲢鳙的摄食促进了浮游动物向小型化方向发展。更多还原

【Abstract】 The influence of silver carp (Hypophthalmichthys molitrix) and bighead (Aristichthys nobilis) on the zooplankton community structure in Donghu Lake, Wuhan was studied using enclosure method during April-July 1990.In the enclosures where silver carp and bighead were stocked ,the average densities of the Protozoa and some small-sized rotifers were high, while those of crustacean and large-sized rotifers were low. In the enclosures without fish,the results were opposite.The average biomass of zooplankton was much higher in the two enclosures without fish (55.035mg/L and 38.374mg/L) than in the two enclosures with fish (3.028mg/L and 3.490rag/L) during April-July 1990.The examination of the size-frequency distributions of the crustacean (copepod nauplius excluded)shows that the frequency of the large-sized crustacean was higher in the enclosures without fish than in the enclosures with fish.The enclosure experimental results show that the feeding of silver carp and bighead resulted in the dominance of small-sized zooplankton instead of large-sized ones.更多还原