Study On Otolith Shape, Taxonomy And Application For Fishes In China Sea

In addition, otoliths are widely used as indicators of fish age and growth at annually, daily and seasonal levels. Recent developments in the tools used for determining otolith's microconstituents have opened up possibilities of studying migrations and stock identity as well as using isotopes to reconstruct past life history of fishes, some good progress has made.The otolith form is species and group specific with the important value for fish taxonomy and systematics research, and some researchers have carried out the massive basic research in the field in recent years. Based on ten thousand otoliths collected from the recent research programms such as "908" special project of State Oceanic Administration of People's Republic of China, National Basic Research Program of China (973 program) (No.2005CB422306), etc., by bio-image analysis software and the mathematical means of Fourier analysis, some fields of fish otolith morphology:Otolith morphological characteristics and measurement methods, otolith morphological diversity, species and stocks identification, morphological changes of otolith growth were carried out. The main findings were as follows:(1)Based on otolith position and posture in the inner ear, in order to facilitate description of the otolith, we call the direction of the head as anterior, the direction of the tail as posterior, the direction of the back as dorsal, the direction of the belly as ventral. In the meanwhile, we give the distinction of the lateral and mesial surface of otolith. Rostrum and antirostrum are created by a nick in the anterior otolith region. Sulcus acusticus exists at mesial surface of otolith.Otoliths collected from 180 Species, belonging to 65 families and 13orders of fishes from China sea were descripted. Most species were from Perciformes, others were from Clupeiformes, Anguilliformes. Myctophiformes, Siluriformes, Gadiformes. Beloniformes, Mugiliformes, Scorpaeniformes and Pleuronectiformes, etc. Otolith shape, size, smoothness degree, sulcus acusticus, rostrum and antirostrum were descirpted in detail; and some measurement characteristic including otolith length, otolith width, perimeter, area, circularity, rectangularity and compactness were analyzed. The preliminary study result showed that the otolith form was species and families specific; sulcus acusticus shape, width, depth, trend etc, may be the important taxonomy characteristic for fishes.Cluster analysis showed that, the Relatives relationship among fishes based on otolith morphology was not entirely overlap with the traditional classification system of fishes. Based otolith form, a systemic taxonomy was designed for 65 families of fishes.(2)Morphological characteristics of otoliths of Japanese sea bass, Lateolabrax japonicus and Chinese sea bass, Lateolabrax maculates from Zhou Shan, Fu Zhou, Xia Men and Guang Xi of China had been compared using coefficient of difference, comparative analysis of Midff and cluster analysis. Significant differences in shape of sagittal otoliths and ralations of otolith weight and length were found between Lateolabrax japonicus and Lateolabrax maculates. Results indicated that the considerable geographical variation existed within stocks of Lateolabrax maculates in China shore. Three geological populations of Lateolabrax maculates:Zhoushan, Fuzhou-Xiamen and Guangxi had probolity of exsiting. Otolith shape was population specific for Lateolabrax maculates.(3)Morphology of otolith was applied to identify Scomberomorus niphonius stocks in Huanghai in this paper. The otoliths of them were collected in Lisi,Ganyu and Jiaonan waters and cluster-analyzed. No significant differences were found between three Lisi specimens and between Lisi and Jiaonan stocks, while siginificant differences were found between Ganyu and other two stocks for some measurments. The Euclidean distances for Lisi and other two stocks were 3.09 and 3.38, while those of the Ganyu and Jiaonan samples was 4.59. Therefore. Lisi and Jiaonan stocks had more relations than others. Otolith morphology has high effectivity for stock identification. (4)Differences in otolith shapes of two fishes:Apogonichthys lineatus and A. arafurae was investigated. A toal of 119 Apogonichthys lineatus and 57 Apogonichthys arafurae Specimens were collected from Beibu Gulf and Bohai Sea between 2006 and 2008 for this study. Otolith length, width, perimeter, area, rectangularity, circularity of the otoliths as well as some Fourier descriptors were analyzed. The results indicted that two kind of fish had the similar overall outline, the sulcus acusticus shape and the edge shape of otolith. Apogonichthys lineatus otolith was egg circle with the wider posterior part, and Apogonichthys arafurae otolith was slender with the narrow posterior part.(5)Monthly variation in otolith shapes of Chelidonichthys spinosus in the Qingdao coastal water was investigated from June to December 2002. A toal of 286 samples were collected from the fishing catches for this study. Otolith length, width, perimeter, area, rectangularity, circularity of the otoliths as well as some Fourier descriptors were analyzed. The results indicted that the otolith was round or quadrangular with a nick in the anterior part. All otolith measurements except for OL/OW (i.e. length, weight and area) were significantly correlated to standard length of the fish. Otolith shapes significantly differed with monthly growth of the fish. Multivariate analysis and canonical discriminant functions found that three phases in otolith shape development were compartmentalized in June, July to September and October to December, respectively.