额尔齐斯河东方欧鳊食性研究

通过分析额尔齐斯河东方欧鳊(Abramis brama)的食物组成、摄食强度和摄食策略,探究其在摄食形态学上的适应性,进一步补充和完善东方欧鳊生物学基础资料,为其人工增养殖提供技术支持。2014年5月至2015年6月,采用三层流刺网、定置刺网和围网,在额尔齐斯河中国段下游分季节连续采集东方欧鳊样本152尾。通过对鱼类样本进行测定、分析和处理,分别对东方欧鳊的摄食强度以及食物组成和摄食策略进行了研究。结果表明,152尾东方欧鳊样品的空肠率为30.92%。根据数量百分比分析,藻类在东方欧鳊食物组成中占绝对优势(99.82%),其中硅藻门的比例最高(73.09%);通过重量百分比、相对重要性指数百分比以及优势度指数指标分析,在每年的5-6月,额尔齐斯河东方欧鳊主要摄食水生昆虫幼体,以摇蚊幼虫为主,藻类在食物组成中的比重极小;Amundsen图示法表明,此时东方欧鳊为偏动物食性的广食性鱼类,且不同个体间食物组成存在一定差异。东方欧鳊的摄食消化器官形态与其食性相适应。

Study on Feeding Habits of Abramis brama in the Irtysh River

Feeding habit is an important component of fish ecology. Analysis of food composition for different fish species provides information on predation and competition and is useful for evaluating the ecological status and function of a species within the fish community. The analysis also provides a theoretical basis for rational utilization of bait resources and estimating fishing yields. In this study, we analyzed the food composition, feeding intensity and strategies of Abramis brama (bream) in the Irtysh River. A. brama is the primary economic fish species in the local area and study results supplement the biological data and provide theoretical and technical support for artificial propagation and breeding of the species. During the study, 152 A. brama were collected from the lower Irtysh River from May 2014 to June 2015. The body length and weight of all specimens were measured, the degree of intestine filling was ranked from 0 - 5. Among the 152 fish examined, filling degree rank was 0 in 47 fish (30.92%) and above 3 in 31 fish (20.39%). Food composition was analyzed in fish with a filling degree rank above 3 and the dominant food of A. brama, calculated as percent by number (PN) of organisms consumed, was algae (99.82%) with Bacillariophyta being most of ten consumed (73.09%). Based on the weight percentage (PW), percentage of relative importance index (PIRI) and dominance index (IP), aquatic insect larvae (especially Chironomidae) was the most important prey. The Amundsen figure analysis indicates that A. brama is euryphagous, with a bias towards to aquatic insect larvae. Food composition displayed little difference among individuals and A. brama feeding and digestive organs were found to be well adapted to observed feeding habits.