Canadian Journal of Fisheries and Aquatic Sciences, Ahead of Print.
Stream habitat changes affecting primary consumers often indirectly impact secondary consumers such as fishes. Blooms of the benthic algae Didymosphenia geminata (Didymo) are known to affect stream macroinvertebrates, but the potential indirect trophic impacts on fish consumers are poorly understood. In streams of the Kootenai River basin, we quantified the diet, condition, and growth rate of species of trout, char, and sculpin. In 2018, macroinvertebrate taxa composition was different between a stream with Didymo and a stream without, but trout diets, energy demand, and growth rates were similar. Trout abundance was higher in the stream with Didymo, but the amount of drifting invertebrates was higher in the stream without. In 2019, we surveyed 28 streams with a gradient of coverage. Didymo abundance was correlated only with the percentage of aquatic invertebrates in trout diets and was not related to diets of char or sculpin or condition of any species. Thus, we found no evidence for a trophic link between Didymo blooms and the condition or growth of trout, char, or sculpin in mountainous headwater streams.

中文翻译：

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硅藻生态系统工程师（Didymosphenia geminata）对流食网的影响：对本地鱼类的影响

《加拿大渔业和水生科学杂志》，印刷前。
影响主要消费者的河流栖息地变化通常间接影响鱼类等次要消费者。底栖藻类Didymosphenia geminata（Didymo）的花开会影响溪流无脊椎动物，但对鱼类消费者的潜在间接营养影响却知之甚少。在库特奈河流域的溪流中，我们对鳟鱼，炭黑和杜鹃鱼的饮食，状况和生长速率进行了量化。在2018年，有Didymo的溪流和没有Didymo的溪流之间的大型无脊椎动物类群组成有所不同，但鳟鱼的饮食，能量需求和增长率相似。戴迪莫河中鳟鱼的丰度较高，而没有狄迪莫河中的无脊椎动物的漂移量较高。在2019年，我们以覆盖率梯度调查了28个流。Didymo的丰度仅与鳟鱼日粮中水生无脊椎动物的百分比相关，而与炭黑或杜鹃的饮食或任何物种的状况无关。因此，我们发现没有证据表明迪迪莫水华与山区源头水域中鳟鱼，炭黑或杜鹃的状况或生长之间存在营养联系。