Establishment and range expansion of non-native species in novel habitats depend on their energetic requirements and food availability. Knowledge of growth and metabolic rates of non-native fishes at various food levels is particularly critical to inform models that assess their invasion potential. We compared growth rates, body condition and metabolic rates of juvenile blue catfish (Ictalurus furcatus), an invasive species in many lakes, coastal rivers and estuaries throughout the Eastern USA, at three ration levels: ad libitum (3.5% of fish body mass/d), two-third ad libitum and one-third ad libitum. All fish survived the entire duration of the experiment (4 months) regardless of ration level. Blue catfish exhibited routine metabolic rates similar to those of other benthic fishes but below the more active species. Mean growth rates were lower at reduced ration levels, but we found no evidence of ration size effect on body condition or metabolic rates. Blue catfish therefore appear to have mechanisms that enable them to survive low rates of food intake for long periods, indicating the potential of this invasive species to become established in habitats with low prey availability.

中文翻译：

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食物限制对非本地蓝鲶鱼生长、身体状况和代谢率的影响

非本地物种在新栖息地的建立和范围扩大取决于它们的能量需求和食物供应。了解非本地鱼类在不同食物水平下的生长和代谢率对于评估其入侵潜力的模型尤其重要。我们比较了幼年蓝鲶鱼（叉鲶鱼）的生长速度、身体状况和代谢率，这是美国东部许多湖泊、沿海河流和河口的入侵物种，在三种配给水平：随意采食（鱼体重的 3.5%/ d)、三分之二随意采食和三分之一随意采食。无论配给水平如何，所有鱼在整个实验期间（4 个月）都存活下来。蓝鲶鱼的常规代谢率与其他底栖鱼类相似，但低于较活跃的物种。日粮水平减少时，平均生长率较低，但我们没有发现日粮大小对身体状况或代谢率有影响的证据。因此，蓝鲶鱼似乎具有使它们能够在低食物摄入率下长时间生存的机制，这表明这种入侵物种有可能在猎物可用性低的栖息地中定居。