本项目在前期研究基础上，拟从螅状体有性繁殖和无性繁殖两种补充途径研究大型致灾水母沙蜇底栖螅状体种群的最有效补充途径与机制。通过同步调查辽东湾沙蜇产卵亲体的时空分布和性腺成熟度、辅助以分子标记技术(如线粒体COI、ITS-5.8S rDNA)查清渤海沙蜇产卵群体的时空分布与移动特征；通过浮浪幼虫对不同附着基的偏好实验以及环境因子对浮浪幼虫变态附着率的影响实验，查清有性繁殖补充途径对螅状体种群补充的最适宜生境条件；通过对自然水域调查和繁育实验观察，从怀卵量-受精卵-8触手螅状体之间的数量转换率角度综合分析沙蜇的有性繁殖对螅状体种群的补充能力。首次通过野外螅状体挂板与室内同步模拟对照结合的方法，进行两代螅状体种群的周年生活史观察，阐明有性繁殖与无性繁殖对渤海沙蜇螅状体种群的相对贡献差异，本研究将进一步揭示沙蜇的暴发机理，为灾害预测及有效治理提供新思路。

Based on our preliminary research result, we will throughout this project, explore the recruitment modes of polyp population based on sexual and asexual reproduction, and blooming potential of the giant jellyfish Nemopilema nomurai in Bohai Sea: (1) Clarify the spatiotemporal distribution and pattern of horizontal migration of N. nomurai mature parent in Liaodong Bay using synchronously surveyed data on abundance and gonadal maturity, by means of molecular characteristics (COI and ITS-5.8S rDNA). (2) Find out the favorable conditions of metamorphosis for planula produced by sexual reproduction through experiments on substrate choice and settlement preferences, and on the effects of temperature, salinity and light on survival rate and adhesion rate. (3) Evaluate the capacity of the sexual reproduction recruitment of adult to polyp population basing on the fecundity data of natural mature medusa obtained from field investigation and on the conversion rate from fertilized eggs to developed polyps with 8-tentecle in laboratory. （4）Compare the capacity of sexual (mature medusa) and asexual reproduction (polyp) and estimate their relative contribution to the original polyp population through a two-year’s synchronous observation on the annual life cycle of two generations of polyp from N. nomurai population, combining field experiment with polyps attached on hanging polyethylene plates and laboratory experiment simulating natural condition in terms of temperature, salinity and light intensity, etc. The results of this study should be essentially used in clarifying the recruitment mode of polyp population based on sexual and asexual reproduction, and would help in determining the probability of future bloom development and in installing effective means and ways of countermeasures.