南海太阳长棘海星的早期发育过程

The early developmental process of Acanthaster solaris in the South China Sea

  • 摘要:
    目的 厘清珊瑚敌害生物长棘海星的早期发育过程,分析其暴发形成的机理。
    方法 针对在南海暴发的太阳长棘海星群体,以繁殖生物学手段开展人工培养实验,比较了不同饵料和附着基对太阳长棘海星浮游幼虫生长存活的影响。
    结果 采用1-甲基腺嘌呤催产剂可以有效促使太阳长棘海星排放配子,经人工授精后,在水温28 ℃和盐度33的天然珊瑚礁海水环境下,可孵化出一批羽腕幼虫。浮游幼虫期间投喂牟氏角毛藻,约12 d后虫体前端形成一对小臂,并发育为有腕幼虫,经2 d的变态期后,获得一批规格为 (445.88 ± 50.63) μm (平均值±标准差)的5腕幼虫,共410只。
    结论 在天然饵料和人工饵料的对比实验中发现,人工饵料并不能促使浮游幼虫发育为有腕幼虫,长棘海星的早期发育仍然需要投喂天然饵料。在有附着基和无附着基的变态对比实验中发现,珊瑚石可有效促进有腕幼虫的变态发育,有附着基变态率平均值为2.59%,显著高于无附着基的0.31%。
    意义 本研究人工繁育出一批太阳长棘海星子代群体,揭示了其早期发育过程,为长棘海星的调查监测、早期预警、减灾防控和灾害处置等工作提供基础资料,对南海岛礁生态安全具有推动作用。

     

    Abstract: Crown-of-thorns sea star (CoTS), a well-known coral predator, has triggered severe ecological disaster on coral reefs in the South China Sea. In order to clarify the early development process of this coral predator and better explain the formation process of CoTS outbreak, an artificial breeding was conducted for the outbreak population of Acanthaster solaris in the South China Sea with the method of reproductive biology. The result demonstrated 1-methyl-adenine was effectively induced to foster A. solaris to spawn. When under the temperature of 28 ℃ and salinity of 33 as the natural seawater of coral reefs, a batch of embryos completed incubation process and developed into bipinnaria larva. With feeding on Chaetoceros muelleri, two newly-formed arm protruded from the anteroventral part of the planktonic larva after 12 d post-fertilization, a feature designated as early branchiolaria larva. Upon two days metamorphosis, larva was successfully developed into 5-arms settled juvenile with totally 410 juveniles and the average size of (445.88 ± 50.63) μm (mean ± SD). It was found that in the comparison between artificial food and natural food, artificial food could not promote the conversion of planktic larvae into branchiolaria larvae and natural food was still needed for the planktic development. Notably, in the experiment of present or absent attached bases, coral stone can effectively promote the metamorphosis development of settled juveniles with the mean metamorphosis rate 2.59%, higher than that of no attached bases with the value only 0.31%. In this study, a number of progenies of A. solaris population were successfully bred in artificial breeding, revealing their early developmental process. The result here provided basic data for investigation, monitoring, early warning, disaster reduction, prevention and control, and disaster management of A. solaris, which finally fostered the ecological security of islands and reefs in the South China Sea.

     

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