三峡库区不同鲢群体耳石微化学差异分析

MICROCHEMICAL DIFFERENCE ANALYSIS OF OTOLITH IN DIFFERENT SILVER CARP (HYPOPHTHALMICHTHYS MOLITRIX) POPULATIONS IN THE THREE GORGES RESERVOIR AREA

  • 摘要: 研究以三峡库区的鲢为研究对象, 通过分析不同群体耳石微化学(微量元素Sr:Ca、Ba:Ca等及稳定同位素δ13C、δ18O)的差异, 探讨鲢耳石微化学组成对栖息环境的指示性, 筛选导致差异的关键指标, 为开展鲢生境履历研究及野生群体和增殖放流群体的鉴别提供新的技术手段。基于耳石边缘区微量元素比值的分析结果表明三峡库区江津区、巴南区、丰都县、太平溪镇等4个样点鲢的判别成功率均值为83.6%, 单因素方差分析显示Li/Ca、Na/Ca、Co/Ca、Sr/Ca、Ba/Ca在4个样点之间存在显著的差异, 主坐标分析结果显示不同样点之间鲢耳石的微量元素比值存在显著差异, 第一成分贡献率较高的指标是Sr/Ca (35.3%)、Co/Ca (28.4%)、Ba/Ca (20.2%), 表明Sr/Ca、Co/Ca、Ba/Ca可以作为鲢生境履历重建研究的关键微量元素指标。基于耳石稳定同位素数据的单因素方差分析显示6个群体的δ13C和δ18O值均存在显著差异, δ13C和δ18O值双位图显示太平溪镇、万州区、丰都县聚为一组, 巴南区、北碚区原种场、巴南区原种场聚为一组, 表明巴南区采集的野外个体可能是来自增殖放流。综上所述, 耳石微量元素Sr/Ca、Co/Ca、Ba/Ca和稳定同位素δ13C、δ18O在不同鲢群体中存在显著差异, 可以作为鲢生境履历重建研究的关键指标, 其中δ13C和δ18O值分析可以有效实现野生群体和增殖放流群体的鉴别。

     

    Abstract: This study focused on silver carp (Hypophthalmichthys molitrix) from the Three Gorges Reservoir area. By analyzing the differences of otolith microchemistry (trace elements Sr﹕Ca, Ba﹕Ca, etc., and stable isotopes δ13C and δ18O) in different populations, the indicator of otolith microchemical composition of silver carp on habitat environment was discussed, and key indicators leading to differences were screened. It provides a new technique for the study of habitat resume reconstruction of silver carp and the identification of wild population and breeding/release populations. Based on the otolith microelement data, relevant statistical analysis was carried out, and the results of discriminant analysis showed that the average success rate of discriminant for four sample sites of silver carp in the Three Gorges Reservoir area was 83.6%. One-way analysis of variance showed that Li/Ca, Na/Ca, Co/Ca, Sr/Ca, and Ba/Ca had significant differences among the four sample populations. The results of principal coordinate analysis showed that there were significant differences in the ratio of trace elements in otoliths of silver carp among different sample sites, and the index with the highest contribution rate of the first component was Sr/Ca (35.3%), Co/Ca (28.4%), and Ba/Ca (20.2%), which indicated that Sr/Ca, Co/Ca, and Ba/Ca were more suitable to be used as the key indicators for the habitat resume reconstruction study of silver carp. Based on the otolith isotope data, relevant statistical analyses were also conducted. One-way analysis of variance showed significant differences in δ13C and δ18O values among 6 populations. The δ13C and δ18O bitmaps showed that Taipingxi, Wanzhou, and Fengdu were grouped together, while Banan, Beibei, and Banan original seed farms were grouped together, which indicated that the sampled individuals in Banan may be from breeding and release to a certain extent. In summary, otolith trace elements Sr/Ca, Co/Ca, Ba/Ca, as well as the stable isotopes δ13C and δ18O, exhibit significant differences among different silver carp populations, which can be used as key indicators for habitat resume reconstruction study of silver carp. Additionally, the analysis of δ13C and δ18O value effectively distinguishes between wild and breeding/release populations.

     

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