Endangered and endemic Razorback Suckers Xyrauchen texanus of the Colorado River basin largely spawn in main-stem rivers and reservoirs. While documenting other native fish use of two intermittent tributaries of the Gunnison River, Colorado, USA, we detected PIT-tagged Razorback Suckers during the 2015–2019 spawning seasons (April–June) and captured reproductively ready individuals. Because the species is rarely documented in small tributaries, we highlight this occurrence. Prior to 2019, up to 30 individual Razorback Suckers were detected annually in Roubideau Creek, a tributary to the Gunnison River near Delta, Colorado. In 2019, use increased as we detected 110 individual Razorback Suckers in Roubideau Creek, and, for the first time, we handled or detected seven in Cottonwood Creek. These fish represented multiple age-classes of hatchery-reared fish repatriated to the Gunnison River to aid recovery. We collected and identified 1,171 larval catostomids from Cottonwood Creek, but none were Razorback Suckers, and even though ripe adults were collected, it remains unclear if reproduction occurred. We suspect that high runoff in 2019 drove increased use of the system. Presence of Razorback Suckers in five consecutive years indicated that intermittent tributaries might be of greater importance than previously thought for this species, and these streams warrant further investigation and protection.

中文翻译：

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Razorback Sucker 在间歇性科罗拉多支流中产卵

濒危和地方性的剃刀背吸盘Xyrauchen texanus科罗拉多河流域的大部分产卵于干流和水库。在记录美国科罗拉多州甘尼森河两条间歇性支流的其他本地鱼类使用的同时，我们在 2015-2019 产卵季节（4 月至 6 月）检测到了带有 PIT 标记的 Razorback Suckers，并捕获了准备好繁殖的个体。由于该物种很少在小支流中记录，我们强调了这一事件。在 2019 年之前，每年在科罗拉多州三角洲附近甘尼森河的一条支流鲁比多溪中发现多达 30 只剃刀背吸盘。2019 年，我们在 Roubideau Creek 检测到 110 只 Razorback Suckers，因此使用量有所增加，并且我们首次在 Cottonwood Creek 处理或检测到 7 只。这些鱼代表了被遣返到甘尼森河以帮助恢复的孵化场养殖的多个年龄级别的鱼。我们从 Cottonwood Creek 收集并鉴定了 1,171 只幼虫 catostomids，但没有一个是 Razorback Suckers，即使收集到成熟的成虫，仍不清楚是否发生了繁殖。我们怀疑 2019 年的高径流推动了该系统的使用增加。Razorback Suckers 连续五年的出现表明，间歇性支流可能比以前认为的更重要，这些河流值得进一步调查和保护。