基于耳石微化学的乌苏里白鲑生境履历分析

为了分析乌苏里白鲑(Coregonus ussuriensis Berg)的洄游生态类型及生境履历, 采用X射线电子探针微区分析技术(EPMA)研究了2013年12月、2014年1月黑龙江干流2尾和松花江干流2尾乌苏里白鲑矢耳石的锶(Sr)、钙(Ca)元素微化学特征。定量线分析结果显示, 乌苏里白鲑耳石锶钙比值(Sr/Ca×103)波动显著, 具有对应淡水生活的低值区(小于5), 而且还有对应咸水生活的高值区(大于10), 显示了乌苏里白鲑的溯河洄游履历; 耳石元素面分析结果也显示乌苏里白鲑的淡水-咸水洄游的特征。结合耳石年轮特征分析, 乌苏里白鲑具有年度(季节)洄游特征, 部分群体有规律在淡水-咸水中季节洄游, 不同个体在淡水、咸水之间停留时间存在较大差异。研究表明, 乌苏里白鲑伴随着季节性洄游特征, 具有江海或者淡水-河口之间洄游的履历。

MICROCHEMISTRY ANALYSIS OF OTOLITHS OF COREGONUS USSURIENSIS FROM THE HEILONG RIVER BASIN

Coregonus ussuriensis, one coldwater fish, is an important economic fishery species in the Heilong River basin. The resources of Coregonus ussuriensis have been seriously impacted by anthropogenic influences such as pollution, habitat degradation and overfishing. Knowing the characteristics of life history at the important stage helps to better protect the Coregonus ussuriensis. Otolith element fingerprint could objectively and specifically reflect the character of the water which fish experienced. The element Sr and Ca microchemistry patterns have been used to reflect the water type which the fish lived in. To study the characteristics of life history for Coregonus ussuriensis, an electron probe microanalyzer (EMPA) was used to analyze the element Sr and Ca microchemistry patterns in otoliths for Coregonus ussuriensis collected from Suibin and Jiejinkou section of the Heilong River main stream and Tangyuan section of the Songhua River main stream from December 2013 to January 2014. Results of line transect analysis indicated the value of Sr/Ca significantly fluctuated including a low ration (<5) responded to freshwater life and some high rations (>10) responded to seawater life, revealing they had experienced an anadromous migration. The results of X-ray mapping analysis of EMPA reflected the same feature of anadromous migration. The annual ring of otolith characters analysis showed the bright and dark belt in the otolith match with the low and high Sr/Ca ratio areas well. It revealed that Coregonus ussuriensis migrate seasonally. Some species migrate to seawater in summer and return back to freshwater in winter regularly, and other species may not have significant regularity. The time of in fresh water and sea water is inconsistent. This study first reported the migratory characteristics of Coregonus ussuriensis, which can provide an important basis for further study on the life history.