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

作为利用耳石中的微量元素重建鱼类生活史的基础研究，对元素在耳石中的掺入进行了研究，考察了环境因素、性成熟和耳石生长速度对金鱼的影响。彩虹鲑鱼中分离的球囊也研究了CA通过球囊膜向耳石的转运。环境中的锶和钡以浓度依赖的方式结合到耳石中，并长期存在而不被动员。这种浓度依赖的掺入不是Al和Fe2的情况。锶在耳石中的掺入不是与锶的绝对量有关，而是与环境中的锶/钙比值高度相关。耳石的锶/钙比值与环境温度呈正相关。雌激素化降低了这一比例，在生长缓慢的耳石中比例很高。CA被细胞内转运到耳石处。在这种情况下，它通过受体控制的钙通道进入球囊细胞，并通过Ca^-lt；2&gt；-ATPase和/或Na^-Ca^&lt；2&gt；交换被泵到耳石一侧。这些结果表明，只有当我们仔细分析数据时，耳石中的微量元素才能为我们提供重建鱼类生活史的良好信息。

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.