日本鳀是一种广泛分布于太平洋西北部水域的小型中上层鱼类，同时也是海洋食物网的关键种，在海洋生态系统物质循环和能量流动中起着重要作用。在过度捕捞等人类活动及全球气候变化的双重影响下，我国日本鳀资源大幅衰退，并已呈现明显的小型化、低龄化趋势。查明日本鳀的种群遗传结构及环境适应的遗传机制，是制定有效保护和合理开发日本鳀生物资源策略的基础。然而，基于传统分子标记的研究对日本鳀种群遗传结构的解析存在较大争议，且在本地适应性方面鲜少涉及。群体基因组学为阐明日本鳀的种群遗传结构及本地适应性进化提供了新的契机。本项目拟采用简化基因组测序技术（RAD-seq）对我国渤、黄、东海日本鳀进行群体基因组学研究，精确解析我国日本鳀的种群遗传结构，阐明产卵群体与越冬场群体间的遗传关系并揭示其洄游路线；探讨不同地理种群对本地环境适应的遗传机制。相关研究结果将为我国日本鳀渔业资源的科学管理及可持续利用提供重要的科学依据。

Japanese anchovy, Engraulis japonicus, is a small pelagic fish distributed in subtropical to temperate waters of the western North Pacific. E. japonicus is a keystone species of marine food web and plays a critical role in the energy flow and nutrient recycling of marine ecosystem. Recently, the resource of E. japonicus has dramatically declined due to climate change as well as anthropogenic activities such as over-exploitation, and a shift towards maturation at smaller size and younger age has also been observed. Investigations of population genetic structure and local adaptation of E. japonicus can provide important information for establishing explicit management and conservation measures for this species. However, previous studies of population genetic structure based on traditional genetic markers obtained discrepant or even conflicting results, and few studies focused on the local adaptation for E. japonicus. Population genomics approaches provide revolutionary opportunities to characterize population structure and genetic mechanism for local adaptation in E. japonicus. By using restriction-site-associated DNA sequencing (RAD-seq), we plan to perform population genomics analyses on E. japonicus distributed in the Bohai Sea, Yellow Sea and East China Sea with two main objectives. First, population genetic structure of E. japonicus will be clarified and relationships between spawning and overwintering populations will be discussed, which will be used to estimate the migration routes of E. japonicus. Second, the genetic mechanism of adaptation to local environments for E. japonicus will be studied. These results will be useful for the management and sustainable utilization of this important fish species in China.