Validation of Daily Increment Formation in Otoliths of Larval Gymnocypris Selincuoensis

Gymnocypris selincuoensis (Cyprinidae: Schizothoracinae) is the only fish living in Lake Selincuo, a high-altitude lake (4,530 m) located in North Qinghai-Tibet Plateau, China. To determine the age of wild larval Gymnocypris selincuoensis, the timing of the first daily increment and the periodicity of increment formation was estimated in hatchery-reared yolk-sac larvae and wild-caught post-yolk-sac larvae marked with environmental stress. The first increment in both the sagitta and lapillus was formed on the first day after hatching and daily periodicity of increment formation was demonstrated in both stages of larval development.