Impacts of environmental variability on the growth and survival of larval sardine and anchovy in the Kuroshio and its extension

为了弄清日本沙丁鱼和日本凤尾鱼在黑潮及其延伸区的生长和生存过程，进行了幼体取样、耳石显微结构分析、环境条件观测和数值实验。在2006-2012年期间，幼虫密度年际波动，反映了各物种总种群丰度水平的波动。然而，空间分布显示出很大的变化，这与黑潮路径的结构有关。粒子追踪实验结果表明，黑潮路径的短期变化极大地改变了幼虫的运输和生长速度。两个物种的生长速率都与温度呈正相关，但以年份划分样本时，两者的生长速度存在显著差异。生存过程被认为是影响这些关系的重要因素。

In order to clarify growth and survival processes of Japanese sardine and Japanese anchovy in areas around the Kuroshio and its extension, larval sampling, otolith microstructure analyses, observations of environmental condition, and numerical experiments were conducted. During the period from 2006 to 2012, larval density fluctuated interannually, reflecting the fluctuations of the abundances of whole stock level of each species. However, spatial distribution showed large variations that were related to the structure of the path of the Kuroshio. The results of particle tracking experiments suggested that short-term variations of the path of the Kuroshio drastically changed the transport and growth rates of larvae. While the growth rates showed positive correlation with temperature for both of the two species, there were significant differences when the samples were divided by years. Survival processes were suggested to be the important factors affecting these relationships.