几种前处理方法所获刀鲚(Coilia nasus)耳石年轮的效果比较

The Comparison of Different Pre-treatment Methods for Acquiring Otolith Annuli of Coilia nasus

本研究较为系统地比较了刀鲚(Coilia nasus)耳石的几种碾磨方法及耳石酸蚀前处理所获刀鲚耳石年轮的效果。结果显示,耳石横截面碾磨法更易获取较为清晰的年轮,而矢状面碾磨法的效果不及前者,但后者在用于耳石微化学的研究中却更有优势。经5%EDTA处理过的耳石,比用1%HCl处理过的耳石,更容易获得较好的年轮效果。本研究还发现,刀鲚耳石年轮形成过程中的一些形态变化,与刀鲚生活史中的生境变化有关联性。

Estuarine tapertail anchovy Coilia nasus has been a highly popular and commercially valuable anadromous species in China the texture of which is delicate. Recently age estimation by otolith of this fish has become a hotspot in ecological research, which largely depends on efficient pre-treatment methods that generate clearer annual rings in the otolith of C. nasus. In this study we compared the effectiveness of several pre-treatment methods. The results showed that the transverse plane was clearer than the sagittal plane through the core; however, the latter was more suitable in some special analysis（especially microchemistry）. Etching with 5% EDTA produced a clearer surface than 1% HCl. Analysis on the rings in the sagittal planes after etching suggested that the morphological change in the otoliths was correlated with transition in the habitat during the lifetime. In conclusion, the transverse plane is suitable for determining the age, and the sagittal plane is optimal in microchemical analysis.