Identification of individuals born in different spawning seasons using otolith microstructure to reveal life history of <Emphasis Type="Italic">Neosalanx taihuensis</Emphasis>

Otolith microstructure was used to distinguish specimens of Neosalanx taihuensis born in spring and autumn. Increment width during the early life stage was significantly narrower for spring-born than autumn-born juveniles, and the frequency distributions of the width of the first 5 increments were distinctive and diagnostic. Otolith growth trajectories and frequency distribution of the first 5 increments of spring-spawning adults displayed similar patterns to spring-born juveniles. Otolith growth trajectories of autumn-spawning adults were intermediate between those of spring- and autumn-born juveniles, and the frequency distribution of the width of the first 5 increments showed two modes, one similar to spring-born juveniles and the other similar to autumn-born juveniles. Populations of N. taihuensis have previously been shown to be dominated by spring-spawning fish. Thus, the putative life history of N. taihuensis can be summarized as: (1) a small part of the spring-born fish mature and spawn in autumn of the year of their birth, (2) the majority of the spring-born cohort matures and spawns in spring of the next year, and (3) offspring of the autumn-born fish mature and spawn in autumn of the following year. This stock-structure information should be considered in fisheries management for this species.