【摘要】 在保安湖一围栏区 ( 3.3hm2 )周年采样 ,共获得可供食性分析用的二龄河蟹 36 2只 (壳宽 1.99— 6 .2 4cm)。胃含物分析表明 ,河蟹为杂食性 ,兼具肉食性倾向 ,以底层群落为食 ,食谱极为复杂 ,包括水生大型植物、藻类 ( 47个属 )、原生动物、轮虫、节肢动物、环节动物、软体动物、鱼类和颗粒碎屑 ,各大类食物的出现频率分别为 87.3%、82 %、0 .3%、0 .6 %、48.2 %、2 8.2 %、0 .3%、2 8.7%、88.7%。而不可分辨物在食物团中较为常见 ,出现频率达 46 .1%。植物性饵料 (大型植物 +藻类 )出现频率为 87.7% ,动物性饵料出现频率 89.8% ;食物团完全由动物性饵料组成的占5 .8% ,完全由大型植物组成的占 5 .3 % ,完全由藻类组成的占 0 .3%。T 检验表明二龄雌、雄蟹在食性方面不存在显著差异。细胞计数表明 ,胃含物中大型植物在数量上比藻类多 2个数量级。作者最后讨论了在河蟹食性分析中的一些难点问题。更多还原

【Abstract】 Gastric mills of 362 specimens of the 2-year-old Chinese mitten crab, Eriocheir sinensis, which contained recognizable food items, in Lake Bao’an were examined. The crab specimens sampled were preserved immediately in 8% formalin and analyzed within 20 days, except specimens in April, May and June which were observed immediately after the crabs were captured. In the laboratory, carapace width (cw) were measured using caliper, and sex recorded. The gastric mills were dissected out, and the food contents of each individual were flushed into a 5 ml plastic tube with 5% formalin and stirred lightly using tweezers to break up and then examined under a binocular microscope at 160× to 600×. All food items were identified to the lowest possible taxonomic level and later sorted into fourteem dietary categories: macrophytes, algae (Cyanophyta, Chlorophyta, Euglenophyta, Bacillariophyta, Xanthophyta), arthropods, oligochaetes, fishes, protozoan, rotifer, gastropods, detritus and the unidentified animal tissue. The results showed that the crab is omnivorous, with tendency for carnivory, feeding on members of benthic communities. The food items’ percent frequency of occurrence was 87.3% (macrophytes), 82%(algae, including 47 genera), 48.2%(arthropods), 28.2%(oligochaetes), 28.7%(fish), 0.3%(protozoans), 0.6%(rotifers), 0.3%(gastropods) and 88.7%(detritus). Unidentified animal tissues were often observed, with an occurrence frequency of 46.1%. In total, the frequency of occurrence of plants (macrophytes+algae) is 87.7% and animals 89.8%. However, 5.8% of the gastric mills was filled only by animals, 5.3% by macrophytes and 0.3% by algae. T-test showed there was no significant difference in food habits between sexes (p>0.05). Correlation analysis indicated that there was no ontogenetic diet shift in the 2-year-old crab. The ratio of cell number of macrophytes to algae was about 118—219:1. Finally, some difficult questions in studying food habits of the crab were discussed.更多还原