Abstract This paper dealt with the predation of juvenile jellyfish Rhopilema esculentum [（21.1±0.4）mm in umbrella diameter] on flounder Paralichthys olivaceus larvae under laboratory conditions. The effects of temperature （15, 19, and 23 ℃）, light regime （light and dark）, and larval size [newly hatched larvae of （3.01±0.08）mm in total length and 5 days post-hatching larvae of （3.79±0.13）mm in total length] on the predation rate were examined at different larval densities. The juvenile jellyfishes were more active and preyed significantly more newly-hatched larvae at higher temperatures （19 and 23℃） than at 15℃. At all larval densities （10, 30, 50, 80ind/L）, the changes of light condition did not affect the predation rates of the juvenile jellyfish on the newly-hatched larvae. Light could not improve the ability of the newly-hatched larvae to avoid predation. The predation rate of the juvenile jellyfish on the 5 days post-hatching larvae was significantly lower than that of the newly-hatched larvae at the higher larval densities （50 and 80ind/L）, but showed no significant difference at the lower larval densities （10 and 30ind/L）. At the lower larval densities, the predation rates of the juvenile jellyfish on larvae were low, which could mask the effect significance that larval size had on the predation rates. The ability of the larvae to avoid predation by juvenile jellyfish was improved as they developed and grew. The larval size effect on the predation rate of the juvenile jellyfish was dependent on larval density.%利用实验生态学方法，研究温度（15、19和23℃）、光照（明和暗）、仔鱼大小[全长（3．01±0．08）mm初孵仔鱼和（3．79±0．13）mm孵化后5天仔鱼]对稚海蜇[伞径（21．1±0．4）mm]捕食褐牙鲆仔鱼的影响。结果表明，稚海蜇对初孵仔鱼的捕食率随着水温升高而显著升高。光照条件在各仔鱼密度（10，30，50和80ind／L）下均不显著影响稚海蜇对初孵仔鱼的捕食率，说明光条件并不显著改善稚海蜇捕食仔鱼的能力。在高仔鱼密度（50和80ind／L）下，稚海蜇对孵化后5天仔鱼的捕食率显著低于对初孵仔鱼的捕食率；但在低密度f10和30ind／L）下，稚海蜇对两个不同发育阶段仔鱼的捕食率之间无显著差异。在低仔鱼密度下，稚海蜇对仔鱼的捕食率较低，这会降低仔鱼个体大小对稚海蜇捕食率作用的显著性。这既表明仔鱼逃避被稚海蜇捕食的能力随其发育生长而提高，也反映了稚海蜇对不同个体大小仔鱼捕食作用受仔鱼密度制约。
展开▼
