长江和闽江水系野生中华绒螯蟹及其养殖子一代形态特征比较

为鉴别长江与闽江野生水系中华绒螯蟹(Eriocheir sinensis)及其养殖子一代,运用基于地标点法的几何形态测量学方法研究两群体野生个体及其养殖子一代头胸甲的形态特征差异。先通过地标点法提取头胸甲上特征点的坐标值,然后进行相对扭曲主成分分析和判别分析来区分4群体头胸甲,最后利用薄板样条分析和网格变形将头胸甲形态变异矢量可视化。结果表明:长江和闽江水系野生个体被完全分为两块较集中的区域,而两野生群体养殖子一代频繁交叉出现,各组不能形成较集中区域;网格变形图显示各群体头胸甲的形态差异主要为额刺和侧刺长度;逐步判别分析中两野生群体的判别准确率均为100%,而两野生群体养殖子一代判别准确率为40%~60%,存在明显的错判风险;聚类分析先将两野生群体养殖子代聚为一类,然后与长江野生个体聚为独立的一支,最终与闽江野生个体相聚。综上,长江与闽江野生中华绒螯蟹形态特征差异较大,但这些形态特征差异在人工养殖一代后基本消失,因此形态学特征不能区分长江与闽江野生中华绒螯蟹养殖子一代。

Landmark-based morphometric identification of wild Chinese mitten crab and their pond-reared offspring originated from the Yangtze River and Minjiang River

Although morphology has been successfully used to distinguish wild Chinese mitten crabs(Eriocheir sinensis)from the Yangtze River and the Minjiang River,whether morphology could be used to identify the pond-reared offspring of these two wild E.sinensis populations still remains unclear.This study was undertaken to examine the morphological difference of wild E.sinensis(G0)from the Yangtze River(YZ)and Minjiang River(MJ)as well as their pond-reared offspring(G1).The results showed that:G0 populations were clearly divided into two independent groups by the first two principal components in the principal component analysis,but the plots were completely overlapped between two G1 populations;the grid distortion map showed that morphological differences of various populations are mainly manifested in the frontal and lateral spines of carapace;the discriminative accuracies of two G0 populations in the stepwise discriminant analysis both are 100%,but the discriminative accuracies of two G1 populations were 40%-60%with obvious misjudgment risk;cluster analysis showed that two G1 populations were clustered firstly and then were clustered with G0 of YZ population,while G0 of MJ population was formed into another distinct cluster.In summary,morphological differences between two wild E.sinensis populations disappeared after one generation of artificial culture,and morphology thus probably cannot be used to distinguish the pond-reared offspring of wild E.sinensis populations originated from the Yangtze River and Minjiang River.