[Discriminant analysis of two Branchiostegus species in the East China Sea based on otoliths and shape morphology]

Population discrimination is the basis of fishery stock assessment. To effectively distinguish Branchiostegus japonicus and Branchiostegus albus in the East China Sea, we measured 28 morphometric characteristics of otolith and 55 morphometric characteristics of shape for 399 Branchiostegus samples (187 B. japonicus and 212 B. albus)collected by deep water drift net in 27°30'-30°00' N and 123°00'-126°30' E from August to October 2021. The data were then analyzed by the variance analysis and stepwise discriminant analysis (SDA). The otolith of the two Branchiostegus species was different in the anterior, posterior, ventral and dorsal sides, while the shape morpholo-gical differences were observed in the head, trunk and caudal areas. The SDA results showed that the discriminant accuracy based on otoliths and shape morphological parameters was 85.1% and 94.0%, respectively. The comprehensive discriminant accuracy was 98.0% based on those two morphological parameters. Our results suggest that otolith or shape morphology could effectively distinguish the two species of Branchiostegus, and that incorporating various morphological parameters could further increase the discrimination accuracy.