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首页> 外文期刊>Canadian Journal of Zoology >Prey-size selection by brown trout (Salmo trutta L.) in a stream innorthern Spain
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Prey-size selection by brown trout (Salmo trutta L.) in a stream innorthern Spain

机译：西班牙北部一条河流中的褐鳟（Salmo trutta L.）选择猎物大小

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摘要

Brown trout in the River Negro in northern Spain preferentially ate larger aquatic prey items (found throughout the water column). A model based on size-dependent prey encounters was able to account for this trend and to generate accurate predictions of the consumption of aquatic prey of different sizes. In contrast, the same model failed to predict the size composition of terrestrial prey (restricted to the upper layers of the water column) eaten by the trout. Trout ignored the larger (more profitable) terrestrial prey, and the consumption of prey of a given size class was more dependent on their relative abundance than on their size. However, the smallest prey were rejected. We suggest that trout were switching, i.e., overexploiting the most abundant prey, because of perceptual limitations mediated by large differences in relative abundance of the different size classes of terrestrial prey. The size-frequency distributions of the available terrestrial prey were always greatly dominated (75-90%) by the two smallest size classes (1-2 and 2-3 mm long), prey over 4 mm long being extremely scarce, while size distributions of aquatic prey were less skewed. Overall, active choice guided by energetic; optimization criteria appeared to be of limited importance in determining the size composition of prey eaten by this population of brown trout Our results also indicate that the operating mechanisms of prey-size selection are probably not independent of the characteristics of the size-frequency distribution of the available prey.
机译：西班牙北部黑人河的褐鳟优先食用较大的水族猎物（遍布水柱）。基于与大小有关的猎物相遇的模型能够说明这一趋势，并能够准确预测不同大小的水产猎物的消费量。相反，同一模型无法预测鳟鱼吃掉的陆地猎物的大小组成（仅限于水柱的上层）。鳟鱼忽略了更大（更有利可图）的陆地猎物，给定大小等级的猎物的消费更多地取决于它们的相对丰度而不是其大小。但是，最小的猎物被拒绝了。我们建议鳟鱼正在转换，即过度利用最丰富的猎物，因为在感知上的限制是由不同大小类别的陆地猎物的相对丰度的巨大差异介导的。可用的陆地猎物的尺寸-频率分布始终被两个最小的尺寸类别（1-2和2-3毫米长）极大地控制（75-90％），超过4毫米长的猎物极为稀少，而尺寸分布水生猎物的偏斜程度较小。总的来说，积极的选择是在精力充沛的指导下进行的;优化标准似乎对于确定该褐鳟种群所吞食的猎物的大小组成具有有限的重要性。我们的结果还表明，选择猎物大小的操作机制可能与鱼的大小-频率分布特征无关。可用的猎物。

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