海月水母在全球范围内大量暴发，严重危害海洋生态系统的健康以及鱼类资源的可持续利用。本文以卤虫无节幼体为饵料，初步研究了水母伞径和饵料密度对海月水母个体捕食率的影响以及海月水母的昼夜捕食节律。研究结果表明，海月水母的伞径对其捕食率的影响极显著（P〈0．01），在1—8cm范围内，随着伞径的增加个体捕食率线性增加，两者之间的关系式为Y=O．044x＋0．125（R2=0．9036）。饵料密度对海月水母捕食率的影响显著（P〈0．05），在0．25—26．11mgC／L范围内，随饵料密度的增加个体捕食率呈线性增加趋势，关系式为Y=0．508x（R2=0．958）。在饵料充足时，海月水母没有昼夜捕食节律。在高饵料密度下海月水母出现过剩捕食，但是捕食行为依然活跃。上述结果既为量化评估海月水母对浮游动物群体的捕食压力提供了基础参数，同时水母过剩捕食行为说明依据生物量和代谢率的推算结果可能低估自然海域水母队浮游动物的捕食压力。%The blooms ofAurelia aurita population greatly damage the health of marine ecosystem and the sustainabil- ity of fish resources utilization. To determine the effects of bell diameters and prey concentrations on the individual feeding rates of Aurelia sp.1, feeding rates of Aurelia sp. 1 on Artemia nauplius were studied in laboratory. Bell diameters signifi- cantly affected the individual feeding rates ofAurelia sp.1 （P〈0.01）. When medusa bell diameters were in the range of 1 to 8cm, the relationship between bell diameters and individual feeding rates was y = 0.044x ＋ 0.125 （R2 = 0.9036）. A signifi- cantly linear relationship was also found between the prey concentrations and individual feeding rates of the medusae （P〈0.05）. In the range of prey concentration, 0.25--26.1 l mgC/L, individual ingestion rates of Aurelia sp. 1 increased with the increase of the prey densities. The relationship was y = 0.508x （R2 = 0.958）. The medusae still fed actively, with even superfluous feeding at high prey concentration. The diel continuous feeding experiments indicated that there was no sig- nificant diurnal feeding rhythm in Aurelia sp. 1 when food resource was sufficient. The findings provided quantitative pa- rameters to evaluate the grazing impacts of Aurelia sp.1 on zooplankton communities. Also superfluous feeding indicated that the grazing impacts predicted by biomass and metabolism of jellyfish was underestimated.
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