Journal of Fishery Sciences of China (中国水产科学) 2013/20:6 PP.1293-1302
We investigated the identification in sagittal otoliths using landmark-based geometric morphometrics method among four sympatric species of the genus Pennahia: truncatetail white croaker P.anea (n=49), bighead white croaker P.macrocephalus (n=50), pawak croaker P. pawak (n=49) and white croaker P.argentata (n=29).The specimens were collected off Beibu Gulf from April 2010 to October 2010. Landmark coordinate values were extracted after otolith digitized by image processing and processed by relative warp principal component (RW), thin plate spline analysis and grad distortion. The 12 RW were then identified using discrimination analysis to differentiate the otoliths of four Pennahia species. The result indicated that, the 1st, 2nd and 3rd RW accounted for 46.57%, 25.39% and 10.02% of the total variation respectively, of which TypeⅠlandmarks 6 and 7, TypeⅡlandmarks 5 and 8 had important contributions, and could explain the most variation. The most morphological variation were displayed in neck, head width pole, and tail of tadpole-shaped sulcus. The gradual discrimination analysis and cross validation indicated that P.anea, P.macrocephalus and P. pawak got average exactitude distinguish ratios of 81.6%~100%, while P.argentata 58.6%, indicating that it contained a potential risk by using the morphology of tadpole-shaped impression owned by Sciaenidae to discriminate the four congeneric Pennahia species. It is necessary to notice this problem in the related otolith morphology research and application in feeding ecology.