A Study on the Reconstruction of Fish Life History Using Trace Elements in Their Otoliths

作为利用耳石中微量元素重建鱼类生活史的基础性研究，本研究对金耳石中微量元素的掺入进行了研究，考察了环境因子、性成熟和耳石生长速率对金耳石的影响。利用离体虹鳟鱼囊研究了Ca跨囊膜向耳石的转运。周围环境中的Sr和Ba以浓度依赖的方式掺入耳石中，并保持很长一段时间而不动员。这种浓度依赖性的掺入与Al和Fe的情况不同。耳石中Sr的掺入量与环境中Sr/Ca比值而非Sr的绝对量有很高的相关性.耳石的Sr/Ca比值与环境温度呈正相关。雌激素处理降低了这一比例，并且在生长缓慢的耳石中这一比例较高. Ca在细胞内运输到耳石。结果表明，微量元素通过Ca ~（2+）-ATP酶和Na ~+-Ca ~（2+）交换作用进入囊状细胞，并被泵出到耳石侧。

As a fundamental study for the reconstruction of fish life history using trace elements in otoliths, the incorporation of the elements into otoliths have been studied.Effects of environmental factors, sex maturation, and otolith growth rate were examined in goldrish. Ca transport to otoliths across the saccular membrane was also examined using the isolated sacculus in rainbow trout.1. Sr and Ba in the ambient environment were incorporated into otoliths in a concentration-dependent way and remained for a long period without mobilization. Such concentration-dependent incorporation was not the case with Al and Fe.2. The incorporation of Sr into otolithe was highly correlated not with the absolute amount of Sr but with Sr/Ca ratios in the environment.3. The Sr/Ca ratio of otoliths showed a positive correlation with ambient temperature. The ratio was reduced by estrogenization and was high in slow-growing otoliths.4. Ca was intracellularly transported to otoliths. In this case, it entered saccular cells via receptor-operated Ca channels and pumped out to the otoliths side by Ca^<2+>-ATPase and/or Na^+-Ca^<2+> exchange.These results indicate that the trace elements of otoliths could provide us with excellent information to reconstruct the life history of fish only when we analyze the date with due caution.