The use of otolith shape to identify stocks of Konosirus punctatus

Konosirus punctatus is an important economic fish in the Northwest Pacific Ocean, especially along the coast of China, and an important substitute in the marine ecosystem. The aim of this study is to quantify the variation of sagittal shapes to discriminate the K. punctatus stocks between China coasts (Wei Hai, Yan Tai, Zhou Shan, Wen Zhou, Dong Ying, Hai Kou and Qing Dao) and Aomori (Am) in Japan by comparing the sagittal morphometric features. The sagitta variation of eight K. punctatus stocks was examined using nine shape indices (Roundness, Circularity, Form-factor, Rectangularity, Ellipticity, Radius ratio, Feret ratio, Aspect ratio and Surface density). Multiple comparisons on shape indices showed that three shape indices (Roundness, Feret ratio and Surface density) have significant differences between nine stocks. The comprehensive judgment accuracy rate is 54.5%. Based on the Fourier coefficient eight Fourier parameters can fit the shape of sagittal. The comprehensive judgment accuracy rate is 56.1%. The results showed that the otolith morphology was not significantly different between seven China stocks, while the China stocks showed a large sagittal morphological difference from the Japanese stock. It could be related to environmental factors and geographical conditions in various sea areas.