长江口中华鲟幼鱼的食物组成及摄食习性

分析了2004年5-9月长江口水域中华鲟幼鱼的食物组成及摄食的月份变化.结果表明:长江口中华鲟幼鱼以底栖小型鱼类、多毛类和端足类为主要食物,兼食虾类、蟹类及瓣鳃类等小型底栖动物.幼鱼的摄食率和摄食强度较高,且摄食强度存在着月份变化.主要饵料生物组成有明显的月变化,且食物个体有逐渐增大的趋势,其中5月主食多毛类和蟹类,6月主食鱼类和端足类,7月为鱼类和多毛类,8月样本较少且为空胃,9月为鱼类和虾类.与历史资料进行比较发现,曾是幼鱼重要饵料的鲬类所占比例极小,其质量百分比仅占1.81%;而以前未曾记录的虾虎鱼类在食物中所占比例较高, 其质量百分比达50.54%;等足类以前也未曾记录,其出现频率达10.07%.

Diet composition and feeding habits of juvenile Acipenser sinensis in Yangtze River estuary

This paper dealt with the diet composition and monthly variation in feeding habits of juvenile Acipenser sinensis accidentally caught along with other fish in Yangtze River estuary from May to September, 2004. The results showed that the juvenile A. sinensis mainly fed on demersal fish, polychaeta and amphipoda, as well as some small-sized benthic invertebrates including shrimp, crab and bivalve. The feeding rate and intensity were higher, and the feeding intensity varied monthly. The main food items also varied monthly, and changed from small-sized to relative largesized species. The main diet composition included polychaeta and crab in May, fish and amphipoda in June, fish and polychaeta in July, empty stomach in August, and fish and shrimp in September. In the diet, the proportion of Platycephalidae, an important prey of juvenile A. sinensis in the past, was very low, only accounting for 1.81% of the total food by mass, while that of Gobiidae and Isopoda, which had not been recorded in the diet, was higher, accounting for 50.54% and 10, 07% of the total, respectively.