| Coilia nasus (CN) was a diadromous fish with high economic value in China. Little information so far has been available on the morphological characteristics and element bioaccumulation of C. nasus among different geological populations. In the present study morphological measures were made with different populations of Coilia nasus (CN), which were collected from Lvsi (LS) and Dasha fishing ground (DS) of the Yellow Sea, Chongming island (CM) of the Yangtze River estuary, Wuhu section in the Yangtze River (WH), Zhoushan Islands (ZS) in the Qiangtang River estuary, and Dongying section in the Yellow River (HH). Furthermore, concentrations of19major and trace elements were determined by ICP-MS by muscle samples of Coilia nasus which were collected from LS, DS, CM, WH, and Coilia nasus taihuensis from Yingxingtan of Taihu Lake. Several multivariate statistical analyses were used to determinate characteristics in different geographical populations.Fourteen morphological traits (e.g., total length, standard length, eye diameter) and20truss network characters were measured with different populations of C. nasus from LS and DS, CM, WH, ZS and HH water areas. Results of multivariate statistical analyses indicated that the sexual size dimorphism was not significant in C. nasus, and there were not significantly differences between male and female individuals except the relative fatness and several traits correlating to the relative fatness. Interestedly, cephalic traits of LSCN, DSCN, CMCN and WHCN were similar, while those of ZSCN and HHCN were relatively unique. The intergraded morphological features of former four populations (i.e., LSCN, DSCN, CMCN and WHCN) were significantly different from the remaining two populations (i.e., ZSCN and HHCN), suggesting that the latter might be relatively independent and weak connectivity of the former populations. Furthermore, the results of this study suggested that C. nasus studied may probably migrate back to their natal river to spawn from oceanic feeding grounds.The concentrations of major and trace element Na, Mg, Al, K, Ca, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Sr, Mo, Ag, Cd, Ba, and Pb in muscle of C. nasus were determined by means of an Agilent7500ce inductively coupled plasma mass spectrometer (ICP-MS). Fe, Mn, Cr, Co, Ni, Cu, Ag, Cd, and Pb were not detected in any muscle sample of five geographic populations. Concentrations of all detected elements had no significant differences between male and female individuals (P<0.05) by Kruskal-Wallis H Test. Zn had the highest concentration among all detected elements in muscle tissues. Several heavy metals (e.g. Cr, Co, Ni, Pb) were not detected, which pose potential health risks to all living organisms. The level of As was also far lower than the corresponding national and international residual limits. In addition, many of the elemental contents were positively correlated with each other. It is noteworthy that different geographical populations of C. nasus could have distinct specialist properties of elements from each other, and LSCN and CNT were relatively unique on principal component1and2, respectively. Furthermore, these five populations could be identified obviously by Discriminant Analysis with a high correct identification rate above80%.In summary, the present study not only revealed morphological characteristics and bioaccumulation properties of elements of different geographical C. nasus populations, but also made the reasonable interpretation of the characteristics and properties. Furthermore, the present study provided many new insights in the habitat, migration and connectivity of C. nasus populations at different water areas, based on data obtained in this study and the habit of migration of C. nasus in previous literatures. |
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