哥斯达黎加外海茎柔鱼耳石的微量元素

Trace elements in the statoliths of jumbo flying squid off the Costa Rica waters

  • 摘要: 实验通过激光剥蚀电感等离子质谱法分析哥斯达黎加外海茎柔鱼耳石的微量元素,了解其微量元素组成及其与表温关系,推测其不同生活史阶段的栖息环境。结果表明,茎柔鱼耳石含有54种元素,其中Ca、Na和Sr为主要元素。总体耳石Sr/Ca大于太平洋褶柔鱼、巴塔哥尼亚枪乌贼和黵乌贼。胚胎期耳石Sr/Ca最高,随着年龄增加而下降。Sr/Ca与表温呈反比例关系。不同孵化月份的茎柔鱼在不同生长阶段的耳石Sr/Ca差异不明显。Ba/Ca可看做茎柔鱼垂直移动的指标元素,茎柔鱼仔鱼至成鱼期耳石Ba/Ca呈“U”型变化,与其幼体生活在海水表层,成体生活在较深层海水相对应。茎柔鱼耳石Mg/Ca核心高外围低,可能与耳石生长率逐渐减小有关,Mg/Ca与表温呈正相关。此外,研究认为茎柔鱼胚胎期是以自身携带的卵黄囊为营养物质,此时耳石的微量元素与亲体的遗传因素相关,与外界水环境无关。

     

    Abstract: Jumbo flying squid,Dosidicus gigas,is the most important commercial fishery in east Pacific Ocean,and the statolith in statocyst is widely applied in the field of population identification,life history analysis and habitat environment.In this paper,we studied the trace element composition of statolith in Dosidicus gigas and its relationship with the corresponding sea surface temperature(SST)by laser ablation inductively coupled plasma mass spectrometry(LA-ICP-MS),then deduced the habitat in different life stages.The results showed that 54 kinds of elements were found in statolith of Dosidicus gigas,calcium(Ca),sodium(Na)and strontium(Sr)are the major elements.Sr/Ca ratio in total statolith is higher than that in Todarodes pacificus,Loligo gahiand Gonatus fabricii.Sr/Ca ratio is the highest in embryonic phase and declined by the age,and its relationship with SST shows a reciprocal ratio.There is no significant difference of Sr/Ca ratio between different hatching months in every life stage.Ba/Ca ratio shows a “U”form from larva to adult,this could be seen as the indicator of vertical movement with larva living in the surface and deep layer for adult.Nucleus is higher than peripheral zone in Mg/Ca ratio which presents positive correlation with SST,and this might be possible with the gradua decrease of growth rate in statolith.Meanwhile,this study also shows that Dosidicus gigasin embryonic phase used its own vitellicle as the nutrient substance,so the trace elements in this phase are related with genetic factor in parent rather than the water environment.

     

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