Monitoring trends in a long‐lived species such as lake sturgeon (Acipenser fulvescens) has it challenges. Targeting the correct life stage to monitor can provide different and contrasting results. Early life stages experience high variable mortality and are often not a good predictor of population trend. Juvenile lake sturgeon (i.e., 5–10 years) experience high survival and could be a good life stage to monitor for assessing population trends. A structured, randomized gillnetting program, Broad‐scale Monitoring, which was selective to juvenile lake sturgeon, was conducted over three cycles (i.e., 5 + years apart) in three contiguous Ottawa River reaches supporting lake sturgeon. In this study, we assessed spatiotemporal changes in juvenile lake sturgeon abundance among cycles, among and within the three river reaches. Density rasters based on catch records of lake sturgeon spatially were created using multilevel B‐splines. Spatial differences in abundance among cycles was determined by obtaining the difference between the rasters. Three cycles of Broad‐scale Monitoring sampled 334 lake sturgeon at a mean CPUE of 0.90 (0.12 SE) sturgeon • gang⁻¹ and a mean total length 673 mm (115 SD) from all three reaches. The relative abundance of juvenile lake sturgeon did not significantly vary among sample cycles, however, CPUE varied within reaches among cycles. There was a spatiotemporal change in density with a decrease in the lowest reach whereas juvenile lake sturgeon density increased the most in the upper reach. The approach used in this study has the potential to monitor spatiotemporal changes in juvenile lake sturgeon abundance populations and may prove effective when assessing rehabilitation or fisheries management efforts.

中文翻译：

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一条大河中幼稚湖st鱼丰度的时空变化

监测诸如st鱼（Acipenser fulvescens）等长寿物种的趋势）面临挑战。针对正确的生命阶段进行监控可以提供不同的对比结果。生命的早期阶段死亡率高，通常不能很好地预测人口趋势。幼年lake鱼（5-10年）存活率很高，可能是监测种群趋势的良好生活阶段。在三个连续的渥太华河支流reaches鱼河段进行了三个周期（即相隔5年以上）的结构化，随机刺刺计划“大范围监视”，该程序对少年lake鱼具有选择性。在这项研究中，我们评估了三个河段之间，周期之间和内部的幼稚湖st鱼丰度的时空变化。使用多层B样条在空间上基于st鱼的捕获记录来创建密度栅格。通过获取栅格之间的差异来确定周期之间的丰度空间差异。三个周期的大规模监测对334个湖st鱼进行了采样，平均CPUE为0.90（0.12 SE）urge鱼•帮派^-1，所有三个射程的平均总长度673 mm（115 SD）。幼稚湖st鱼的相对丰度在样品周期之间没有显着变化，但是，CPUE在周期之间的范围内变化。密度发生时空变化，最低河段减少，而幼湖lake鱼密度在上游增加最大。本研究中使用的方法具有监测幼稚湖st鱼丰度种群时空变化的潜力，并可能在评估恢复或渔业管理工作时证明是有效的。