Paszkowski Cynthia A
Center for Limnology and Department of Zoology, University of Wisconsin-Madison, 53706, Madison, WI, USA.
Oecologia. 1985 May;66(2):271-279. doi: 10.1007/BF00379865.
The central mudminnow (Umbra limi) and yellow perch (Perca flavescens) are two species of fishes that commonly co-occur in small bog lakes in the Great Lakes region of North America. Both species are dietary generalists with a high degree of dietary overlap, and perch populations have been shown to have a strong negative effect on mudminnow populations. I compared the foraging rates of the two species in a series of laboratory experiments in which four foraging sites were simulated (open bottom substrate, water column, submerged aquatic macrophytes, and water surface). Fish were observed as they foraged singly, in monospecific pairs, and in mixed species pairs to evaluate the effects of intra- and interspecific competition on foraging success and the potential for resource partitioning based on foraging site. Single species trials showed that each species had similar foraging rates at each of the four sites. Across all sites combined, interspecific competition had a greater negative effect on the foraging success of mudminnows than did intraspecific competition. Conversely, intraspecific competition had a greater negative effect on the foraging success of perch than did interspecific competition. In mixed species trials perch took more food items from each of the four foraging sites than did mudminnows and caused shifts in site-use patterns of mudminnows. Differences in the foraging success of the two species reflected the superior ability of perch to discover the presence of food and to search rapidly for additional items, but were unrelated to handling times. These differences were linked to the species' foraging modes. The competitive superiority of perch, demonstrated in these experiments, could contribute to the negative impact of perch on mudminnow populations under natural conditions.
中部泥狗鱼（Umbra limi）和黄鲈（Perca flavescens）是北美洲五大湖地区小型沼泽湖泊中常见的两种鱼类。这两个物种都是食性广泛的物种，食性重叠程度很高，并且已表明鲈鱼种群对泥狗鱼种群有很强的负面影响。我在一系列实验室实验中比较了这两个物种的觅食率，实验模拟了四个觅食地点（底部开放基质、水柱、沉水水生植物和水面）。观察鱼类单独觅食、单物种配对觅食和混合物种配对觅食的情况，以评估种内和种间竞争对觅食成功率的影响以及基于觅食地点进行资源划分的可能性。单物种试验表明，每个物种在四个地点中的每个地点的觅食率相似。综合所有地点来看，种间竞争对泥狗鱼觅食成功率的负面影响比对种内竞争的影响更大。相反，种内竞争对鲈鱼觅食成功率的负面影响比对种间竞争的影响更大。在混合物种试验中，鲈鱼从四个觅食地点中的每个地点获取的食物比泥狗鱼多，并导致泥狗鱼的觅食地点使用模式发生变化。这两个物种觅食成功率的差异反映了鲈鱼发现食物存在并迅速寻找其他食物的能力更强，但与处理时间无关。这些差异与物种的觅食方式有关。在这些实验中表现出的鲈鱼的竞争优势，可能是导致自然条件下鲈鱼对泥狗鱼种群产生负面影响的原因。
