长江宜宾江段铜鱼属鱼类种间食物关系

Interspecies diet relationship of Coreius from Yinbin reach of Yangtze River,China

采用碳、氮稳定同位素技术对2012年4—5月长江宜宾江段铜鱼和圆口铜鱼的食物组成进行了分析,并利用多元统计分析方法探讨了铜鱼和圆口铜鱼种间食物关系,包括饵料相似性指数、重叠系数及2种鱼的摄食器官形态差异对食物组成的影响.结果表明:1)铜鱼的δ13C和δ15N变化范围分别为-21.15‰^-20.31‰和9.67‰~10.21‰,为偏动物性的杂食性鱼类;圆口铜鱼的δ13C和δ15N分别为-23.30‰^-21.18‰和7.40‰~9.21‰,相对铜鱼为偏植物性的杂食性鱼类,铜鱼和圆口铜鱼均与传统肠含物分析的结果存在一定的差异;2)两种鱼的食物相似性指数和食物重叠系数分别为78.7%和55.6%;3)主成分分析(PCA)表明,铜鱼和圆口铜鱼摄食器官形态特征存在一定的差异.长江宜宾江段铜鱼和圆口铜鱼种间竞争不激烈,作为向家坝蓄水前最后一次对长江宜宾江段铜鱼和圆口铜鱼食性及种间食物关系的调查,研究结果可为分析向家坝蓄水对宜宾江段鱼类营养结构的影响提供数据参考.

This study investigated the diet compositions of Coreius heterodon and C. guichenoti in Yibin reach of Yangtze River from April to May, 2012 by carbon and nitrogen stable isotopes tech- nique, and analyzed their diet relationship by the multivariate statistical technique, which covered the diet similarity index, overlap coefficient, and the influence of morphological differences in feed- ing organ between the two species on diet compositions. The results showed that, 1 ） the δ13C and δ15N of C. heterodon was from -21.15‰ to -20.31‰ and 9.67‰ to 10.21‰, respectively, which indicated that the fish had an omnivorous possessing carnivorous preference. The δ13C and δ15N of C. guichenoti was from -23.30‰ to -21.18‰ and 7.40%0 to 9.21‰, respectively, which had an omnivorous possessing phytophagous preference. There were some differences in the results between the stable isotopes and the traditional intestinal contents analysis. 2） The diet similarity index and the overlap coefficient was 78.7% and 55.6%, respectively. 3） The principal component analysis （PCA） result showed that the morphological characters of the feeding organs in the two fishes were different. In conclusion, the interspeeies competition was not intense between the C. heterodon and C. guichenoti, and as the last investigation of the diet composition and food relationship of the two species before the impoundment of the analyzing the influence of impoundment Xiangjiaba Reservoir, the results could provide reference for on the fish trophic structure in Yibin reach of Yangtze River.