摘要
利用电子探针微区分析技术,对2014年8月1日采自江西省余干县瑞洪镇信江(鄱阳湖水系五大河流之一)江段的刀鲚(Coilia nasus)的矢耳石进行了锶和钙的微化学分析研究。元素定量线分析表明,样品的锶钙比值(Sr/Ca×103)波动显著,不仅具有对应淡水生活的低值(Sr/Ca×103<3),而且出现了对应于海水生活的高值(3<Sr/Ca×103<7),显示出其典型的溯河洄游特征。耳石Sr含量的面分析结果与之相同,均具有对应淡水生活的低值(蓝色)区域和海水生活的高值(绿色)区域。这两种耳石微化学类型首次直观地证实,目前距长江河口约1000 km的信江中存在洄游型刀鲚。
The estuarine tapertail anchovy Coilia nasus （Clupeiformes, Engraulidae） is a highly commercial mi-gratory fish species in the Yangtze River. Because of adverse human activities such as overfishing, C. nasus pro-duction has sharply declined. Investigating the large-scale distribution of this fish is very important for evaluation of its resources and habitat. Previous evidence revealed the existence of anadromous C. nasus in Poyang Lake;this study was conducted to confirm whether there is also anadromous C. nasus in the Xinjiang River. An electron probe microanalyzer was applied to analyze Sr and Ca microchemistry patterns in otoliths of C. nasus collected from the Ruihong section of the Xinjiang River （the most distant branch of Poyang Lake, ~1000 km from the Yangtze River estuary） near Yugan County in Jiangxi Province. Line transect results clearly showed a complex Sr/Ca ratio （i.e., Sr/Ca×103） pattern, including low-ratio freshwater habitat （Sr/Ca×103〈3） and high-ratio seawater habitat （3〈Sr/Ca×103〈7）, which clearly demonstrates that the anchovies had experienced anadromous migration. These two microchemistry patterns verify, for the first time, the existence of anadromous C. nasus in the Xinjiang River. Home spawning is thought to be the main reason for such a long migratory for the anchovy in the Xinjiang River, resulting from natural selection for relatively stable spawning conditions. A 1000-km migratory distance reflects an extremely strong migration ability of C. nasus, which is a relatively small fish. The anchovies enter into the Xinjiang River to visit habitat required for spawning and early life stages, and there are likely spawning grounds of anadromous C. nasus in this river.
出处
《中国水产科学》
CAS
CSCD
北大核心
2015年第5期978-985,共8页
Journal of Fishery Sciences of China
基金
国家自然科学基金面上项目(31372533)
关键词
刀鲚
耳石
电子探针
信江
鄱阳湖
Coilia nasus
otolith
electron probe microanalyzer
Xinjiang River
Poyang Lake
