Otolith chemical signatures of spottedtail goby Synechogobius ommaturus in coastal waters of China

This study explores the potential existence of local stocks of Synechogobius ommaturus using otolith chemical signatures. The concentrations of 10 elements （K, Ca, Na, Mg, St, Pb, Ba, Mn, Co, Zn） in the otoliths from eight stocks （Dandong, Dalian, Tianjin, Dongying, Weihai, Qingdao, Ganyu and Xiamen） ofS. ommaturus were measured by Inductively Coupled Plasma Mass Spectrometry and regressed against otolith weight. No significant correlation between otolith weight and concentrations of Na, Mg, Ca, Sr, Co, Ba, Zn and Pb were observed. Concentrations of K and Mn were correlated with otolith weight. Consequently, the residuals of the regressions were used instead of the original concentrations in subsequent analyses. Analysis of variance （ANOVA） showed no significant difference between males and females in otolith chemical signatures. Differences were found among the locations for K, Sr, Mn, Co, Ba, Pb, but not for Ca, Na, Mg and Zn. Residuals of the regressions of elemental concentrations against otolith weight that fitted the normal distribution and homogeneity were studied by discriminant analysis. The success of the discriminant function to predict the location of S. ommaturus capture ranged from 100% for Weihai and Xiamen stocks, to only 44.4% and 62.5% for Qingdao and Dandong stocks, respectively. The average prediction success was 80.3%.

Morphological Variation of Coilia Mystus （Clupeiformes： Engraulidae） in Three Chinese Estuaries

Truss network data were collected and investigated in order to clarify the morphological variation in populations of Coilia mystus from three Chinese estuaries. Nineteen morphometric measurements were made for each individual, and Burnaby＇s multivariate method was used to obtain size-adjusted shape data. The cluster analysis and discriminant analysis were used to discriminate morphological differences among populations. The results indicated that 1） the three populations were clustered into two distinct groups： the first group included Changiiang C. mystus and Zhujiang C. mystus, the last one included Minjiang C. mystus, and 2） discriminant analysis with selected 5 morphological parameters showed that the identification accuracy was between 98.7952% and 100%, and global identification accuracy was 99.2933%. Reproductive isolation and adaption to environmental condition are determinant factors for morphological variation between populations of C. mystus.

Comparative morphometrics of two populations of giant river catfish (Mystus seenghala) from the Indus river system

Giant river catfish (Mystus seenghala) from the Beas river were compared with a population in the Sutlej river of theIndus river system using 28 morphometric characters. Discriminant analyses and a univariate ANOVA were used toexplore these data. Allometric transformation of each measurement was done to eliminate correlations with size. Thestepwise discriminant analysis retained nine variables that significantly discriminated the Beas samples from theSutlej samples. Using these variables, 91.2% (original) and 89.0% (cross validated) of fish were classified into theircorrect samples. Misclassification was higher for the Sutlej samples (12.5%) than for the Beas samples (6.3%). Theresults of the discriminant analyses showed that variability in the Beas samples was more homogeneous andprovided a more characteristic picture of the group than the Sutlej samples. The univariate ANOVA revealed significantdifferences between the means of the two populations for 12 of the 28 transformed morphometric measurements.