大型水母幼体生长的影响因子研究进展

21世纪以来,中国东、黄海,韩国西海岸以及日本海连年发生大型水母暴发现象,对海洋渔业的生产活动以及海洋生态系统带来巨大的影响。水母暴发形成机制非常复杂,解释其发生机理并有效预报是目前急待解决的问题。大型水母的生活史中有明显的世代交替现象,受精卵,浮浪幼虫,螅状体,足囊,横裂体到碟状体的幼体发育阶段属无性世代,幼蜇发育到成蜇阶段属有性世代。在早期生活史中,螅状体的足囊繁殖与横裂生殖是大型水母无性繁殖的重要方式,对其成体的数量形成至关重要。综述了国内外有关温度、盐度、光以及营养条件对大型水母早期发育阶段的影响研究进展,研究表明温度是影响螅状体发育以及足囊繁殖和横裂生殖的最主要的环境因子;盐度、光和营养条件在适温范围内,均对螅状体和横裂生殖有一定的影响,其上下限随水母种类和发育阶段有所变化。展望了大型水母早期幼体研究的发展趋势,如环境因子对不同种类的大型水母幼体生长机理的影响、多个环境因子对幼体的综合作用、动态的环境因子与大型水母幼体之间的关系等。

Research progress on the environmental factors on the larval growth of giant jellyfish

Since the beginning of this century, the giant jellyfish blooms which seriously damaged local fisheries and marine ecosystem, appeared in the Northern part of the East China Sea and the Yellow Sea, Western coastline of Korea and the Sea of Japan in successive years. Yet the environmental factors that control the sizes of jellyfish populations are not well understood due to the complexity of the mechanism of the giant jellyfish blooms. The giant jellyfish (Cnidaria) exhibit two types of reproduction, one is asexual reproduction, including fertilized eggs, planula, scyphistoma, podocyst, strobila and ephyra; the other is sexual reproduction, including medusa or jellyfish, typically solitary, pelagic. In the early life history, podocyst generation and strobilation which determined the number of medusa ultimately, were two important modes of asexual reproduction. The effects of temperature, salinity, light and nutrition on the larva of giant jellyfish, were reviewed and indicated that temperature is one of the main factors influencing the asexual reproduction. Factors including salinity, light and nutrition had a certain effect on the larval growth at the optimal value range of temperature, and the adaptive range of factors changed with the species and larval development. At last the article prospected the future study about the effects of environmental factors on different species larvae of giant jellyfish; the combined effects of environmental factors on the larval growth of giant jellyfish; and relation between the dynamic environmental factors and the larval growth.