Channel catfish are important to the Mississippi River (i.e., ecologically, commercially, and recreationally). The dynamic rate functions (recruitment, growth, and mortality) of the population are important to proper management. However, different gears can produce varying estimates of these vital rates (e.g., size selectivity or age selectivity). We evaluated the effectiveness of three commonly used gear types for sampling channel catfish. Sampling was completed following United States Army Corps of Engineers' Long-Term Resource Monitoring (LTRM) element sampling protocol; pulsed direct current daytime electrofishing, baited 37 mm hoop nets (large hoop net), baited 18 mm hoop nets (small hoop net), and a tandem hoop net set that included one large and one small hoop net. A total of 65,222 channel catfish were collected from 1993 to 2017. Channel catfish catch rates were lowest using daytime electrofishing and large hoop nets, while tandem hoop nets and small hoop nets had higher catch per unit effort (CPUE). Furthermore, tandem hoop nets collected a broader size distribution of channel catfish in comparison to daytime electrofishing, large hoop nets, and small hoop nets. As such, we recommend that tandem hoop nets should be used to evaluate channel catfish populations in the Upper Mississippi River as well as other riverine systems.

中文翻译：

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密西西比河上游沟鲶的特定渔具捕获率和大小结构

鲶鱼对密西西比河很重要（即在生态、商业和娱乐方面）。人口的动态比率函数（招募、增长和死亡率）对于适当的管理很重要。然而，不同的齿轮可以对这些生命率产生不同的估计（例如，尺寸选择性或年龄选择性）。我们评估了三种常用渔具类型对沟鲶采样的有效性。采样是按照美国陆军工程兵团的长期资源监测 (LTRM) 元素采样协议完成的；脉冲直流日间电捕鱼、带饵的 37 毫米环网（大环网）、带饵的 18 毫米环网（小环网），以及包括一个大环网和一个小环网的串联环网组。从 1993 年到 2017 年，总共收集了 65,222 条鲶鱼。使用日间电捕鱼和大环网的沟鲶捕获率最低，而串联环网和小环网的单位努力捕获量 (CPUE) 更高。此外，与白天的电捕鱼、大箍网和小箍网相比，串联箍网收集了更广泛的沟鲶尺寸分布。因此，我们建议应使用串联箍网来评估密西西比河上游以及其他河流系统中的沟鲶种群。