Analysis of morphological differences between natural and cultured populations of Oplegnathus fasciatus

In order to effectively distinguish the natural population from the cultured population of Oplegnathus fasciatus, this study randomly selected 226 samples (126 from the natural population and 100 from the cultured population) and measured seven and thirty-six measurable traits by traditional morphometry and the truss network, respectively, and carried out difference analysis and stepwise discriminant analysis. The results of difference analysis showed that four of the six measurable traits (excluding body length) were extremely significantly different (P＜0.01), and two of them were significantly different (P＜0.05) according to traditional morphometry, while 31 of 36 measurable traits were extremely significantly different (P＜0.01) and five of them were significantly different (P＜0.05) according to the truss network. These results indicated that there were significant differences in the morphological characteristics between the natural and cultured populations, mainly in the head, trunk and pelvic fin. The results of stepwise discriminant analysis showed that the correct rate of discrimination were 97.8% and 94.7%, respectively, after cross-validation based on the traditional morphometry and truss network, and the correct rate of discrimination was 99.6% after cross-validation based on the comprehensive analysis combined with the two methods. The above results showed that it is feasible to discriminate the natural and cultured populations via morphological methods, and the results of the comprehensive discrimination can be more accurate when various morphologically measurable traits were combined.