The Northern Snakehead Channa argus, a species originating from Asia, was illegally introduced into ponds of Maryland in 2002. Later discovered in tidal freshwater of the Potomac River, the species has become successfully established in many Maryland rivers. The magnitude of impact on preferred prey of Northern Snakehead in North American ecosystems has not been widely studied, leaving unresolved whether there are deleterious effects owed to introduction. To add insight into potential impacts of Northern Snakeheads, we calibrated a published, temperature-dependent maximum consumption model using field data and informed its results with diet and prey preference data to compare consumption levels among prey species. The total annual maximum consumption estimated from the model for a population of 600 Northern Snakeheads, which is an abundance approximated from published population sizes in streams of the Potomac basin, amounted to consumption of 2,189 kg of fish for the population per year. We found no evidence of strong prey preferences and partitioned this consumption to relative proportions of some fishes preyed on by Northern Snakehead as 661 kg/year of sunfishes Lepomis spp., 522 kg/year of Yellow Perch Perca flavescens, 332 kg/year of Goldfish Carassius auratus, 250 kg/year of White Perch Morone americana, and 174 kg/year of Banded Killifish Fundulus diaphanus. Some of these coastal fishes comprise important recreational and commercial fisheries. The maximum consumption estimates modeled here are greater than would be observed naturally, and whether predation affects persistence of the prey species in the ecosystem will depend upon the resiliency of the prey population and its current population size, which are unknown. We conclude that, as indicated by earlier risk assessments, the Northern Snakehead is an important predator in Maryland ecosystems because it is opportunistic and is capable of consuming significant biomasses of several recreationally and commercially important fish species.

中文翻译：

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使用已发布的信息来预测马里兰州北蛇头的消耗量

The Northern Snakehead Channa argus2002 年，一种原产于亚洲的物种被非法引入马里兰州的池塘。后来在波托马克河的潮汐淡水中发现，该物种已在马里兰州的许多河流中成功定殖。对北美生态系统中北蛇头首选猎物的影响程度尚未得到广泛研究，因此尚未解决是否因引入而产生有害影响。为了深入了解北方蛇头的潜在影响，我们使用现场数据校准了一个已发布的、与温度相关的最大消费模型，并使用饮食和猎物偏好数据告知其结果，以比较猎物物种之间的消费水平。根据模型估计的 600 只北方蛇头种群的年度最大消费总量，这是根据波托马克盆地河流中公布的种群规模近似得出的丰度，相当于该种群每年消费 2,189 公斤鱼。我们没有发现强烈的猎物偏好的证据，并将这种消费划分为北方 Snakehead 捕食的一些鱼类的相对比例为 661 公斤/年的翻车鱼Lepomis spp.，522 kg/年 Yellow Perca Perca flavescens，332 kg/年 Goldfish Carassius auratus，250 kg/年 White Perch Morone americana和 174 kg/年 Banded Killifish Fundulus diaphanus. 其中一些沿海鱼类包括重要的休闲和商业渔业。这里模拟的最大消耗估计值比自然观察到的要大，捕食是否影响猎物物种在生态系统中的持久性将取决于猎物种群的弹性及其当前种群规模，这是未知的。我们得出的结论是，正如早期的风险评估所表明的那样，北蛇头是马里兰州生态系统中的重要捕食者，因为它是机会主义的，并且能够消耗几种重要的娱乐和商业鱼类的生物量。