| 摘要: |
| 随着长江禁渔国策的持续实施，长江干流和沿线通江湖泊中刀鲚资源及其关键栖息地将有可能得到恢复. 为了确证长江禁渔后的2020年在鄱阳湖永修瓢头水域所采集到21尾刀鲚的洄游履历和资源类型，本研究采用电子探针微区分析技术（EPMA）对其耳石元素锶（Sr）和钙（Ca）的微化学特征进行了测定和分析. 结果显示，所有个体耳石的Sr/Ca比值变化较为复杂. 自耳石核心至边缘Sr/Ca值分别出现了对应淡水生境的低值（＜3）和对应河口半咸水或海水生境的中高值（＞3），最后边缘部分再次出现了对应洄游返回淡水生境的低Sr/Ca值（＜3）. Sr含量面分析图中也呈现出了相应的淡水-河口半咸水-海水-淡水的蓝色-黄绿色、红色-蓝色变化的图谱；证明上述个体均具有明显的江海洄游特征，为典型溯河洄游型刀鲚. 鄱阳湖永修瓢头水域是一处尚未曾正式报道过的洄游性刀鲚分布区. 根据性成熟度和摄食情况可将瓢头水域刀鲚分为产卵场群体和非产卵群体两类. 通过与鄱阳湖其他水域刀鲚情况的比较分析可以推定，两类刀鲚可能起源于鄱阳湖内两个不同区域的产卵场. 对于产卵场群体而言，瓢头水域可能更主要起到产卵场的作用；而对于非产卵群体来说，瓢头水域更多地起到洄游通道作用. 本研究可为了解长江禁渔对刀鲚资源和关键栖息地的恢复效果提供最新的基础信息. |
| 关键词: 刀鲚 耳石微化学 鄱阳湖 永修水域 长江禁渔 溯河洄游 |
| DOI： |
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| 基金项目:国家重点基础研究发展计划（973计划） |
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| Identification of key habitats of Coilia nasus in Poyang Lake based on otolith microchemical characteristics |
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Xiao Baiyi,Yang Jian,Jiang Tao,Liu Hongbo,Chen Xiubao
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Wuxi Fisheries College, Nanjing Agricultural University
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| Abstract: |
| With the continuous implementation of Yangtze River Fishing Ban policy, the Coilia nasus resources and their key habitats in the main stream of the Yangtze River and the lakes along the Yangtze River will be possibly restored. For confirmation of the migration history and resource ecomorphotype of 21 individuals of Coilia nasus collected in the Piaotou water area of Yongxiu County in the Poyang Lake in 2020 after enacting the fishing ban policy, the microchemical characteristics of strontium (Sr) and calcium (Ca) in their otoliths were measured and analyzed using the approach of electron probe microanalysis (EPMA). The changes in otolith Sr/Ca ratios of all individual were relatively complex. From the core to the edge of the otoliths, the Sr/Ca values appear sequentially at low values corresponding to freshwater habitats (<3) and at medium high values corresponding to estuarine brackish or seawater habitats (>3), and at low Sr/Ca values again corresponding to migration back to freshwater habitats (<3) respectively. The Sr content mapping analysis also showed the corresponding blue (freshwater) -yellow/green (estuary brackish water) color and red (seawater) –blue (freshwater) color maps, proving that the above individuals were all typical anadromous ecomorphotype C. nasus. The Piaotou water area of Yongxiu County in the Poyang Lake would be a distribution area of the ecomorphotype C. nasus that had not yet been reported. According to sexual maturity, the C. nasus from the Piaotou water could be divided into spawning group and non-spawning group, respectively. Through comparative analysis of the situation of C. nasus in other waters of the Poyang Lake, it can be inferred that the two fish groups might originate from different spawning grounds in the Poyang Lake. For C. nasus in non-spawning group, the Piaotou water seemed to mainly play the role of migratory channels while for those in spawning group the water might mainly play the role of spawning site. The present study can provide valuable basic information for understanding the restoration of C. nasus resources and key habitats in the Yangtze River benefited from the fishing ban in the Yangtze River. |
| Key words: Coilia nasus otolith microchemistry Poyang Lake fishing ban in the Yangtze River Yongxiu water anadromy |
