积温与饵料量增加在沙蜇暴发形成中的作用机制

The rhizostome jellyfish Nemopilema nomurai, which is endemic to the East Asian Marginal Seas (i.e. the Bohai, Yellow, East China and Japan Seas), is unique both by its enormous body size and biomass. Frequent occurrences of jellyfish blooms can apparently be a threat to the fisheries sustainability of the East Asian Marginal Seas, one of the world’s most productive fisheries grounds. In preliminary studies, we have found the temperature and food regimes significantly improved the somatic growth and podocyst reproduction. In this experiment, a useful method of experimental ecology will be used to study the dynamic change of podocyst reproduction and explore the difference of relative contribution to polyps population quantity between the asexual reproduction and sexual reproduction in different accumulated temperature area which indicated the short and long-term effect of accumulated temperature and food regimes increasing on polyps and medusae population quantity at the key period. Results can be of value in understanding dynamic processes, of polyps populative structure and revealing the outbreak mechanism. Knowledge of the dynamic change of podocyst reproduction could prove beneficial to the abundance of scientific reference data for monitoring and controlling of Nemopilema nomurai bloom, and provide a scientific basis for emphasizing the key environmental monitoring period and strengthening early warning.

沙蜇(Nemopilema nomurai)是东亚水域大型致灾水母中个体最大、生物量最高、影响范围最广的种类，其暴发严重影响了海洋渔业生产，给沿岸各国的渔业经济带来巨大损失，已经成为一种新型的海洋生态灾害。我们在前期研究中发现水温与饵料量增加有利于沙蜇螅状体个体生长与无性繁殖，本项目拟采用模拟生态实验方法研究不同积温海区沙蜇足囊繁殖的周年动态变化过程，探究不同积温海区沙蜇无性繁殖与有性繁殖对其螅状体种群数量的相对贡献差异；阐明沙蜇暴发形成过程中能使积温起主要效应的关键时期；并在此基础上，针对关键时期研究积温与饵料量增加对沙蜇螅状体与水母体种群数量的短期与长期影响。研究结果对摸清沙蜇螅状体种群结构组成的季节动态变化、深入了解沙蜇生活史及揭示暴发机理具有非常重要的意义，也可为沙蜇暴发预警及有效治理提供科学准确的参考数据，同时可为暴发预警确定重点环境监测期提供科学依据。

沙蜇是东亚水域大型致灾水母代表种类，本项目采用室内模拟生态实验的方法，研究了春季不同升温条件对沙蜇螅状体横裂生殖的影响，定量和系统研究了水温和饵料量对沙蜇足囊繁殖及沙蜇幼水母生长的影响，明确了沙蜇浮浪幼虫的适温范围，采用逐个细观与宏观数量统计相结合的模拟生态实验方法，研究了高、低积温海区沙蜇螅状体种群的周年动态变化，推理了沙蜇螅状体种群在不同积温海区的数量变动差异模式图，证明了螅状体种群有能力在环境适宜的条件下通过自身足囊繁殖恢复种群数量，从底栖生态的角度分析了对沙蜇暴发起主要影响作用的关键生活史阶段，阐明了关键期的积温与饵料量增加在沙海蜇暴发形成中的作用机制，绘制了中国北部海区沙蜇周年生活史示意图。项目研究成果对摸清沙蜇螅状体种群结构组成和季节动态变化，深入了解沙蜇生活史及揭示暴发机理具有非常重要的意义，也可为沙蜇暴发预警及有效治理提供科学准确的参考数据，同时可为暴发预警确定重点环境监测期提供科学的基础资料。