The age-0 abundance of eight sport fish species in the four mainstem Missouri River reservoirs in South Dakota was evaluated to estimate the influence of environmental and biological factors on age-0 species abundance. Datasets (at least ten consecutive years) from each reservoir were analysed to evaluate the effects of both monthly (i.e. gauge height, temperature and precipitation) and annual (i.e. cooling degree days and heating degree days, minimum, average, and maximum temperature, and average precipitation) environmental and biological factors. Biological factors including age-0 prey fish abundance (i.e. gizzard shad Dorosoma cepedianum [Leseuer] abundance), age-0 sport fish abundance and adult sport fish abundance were examined. Factors were included that are known to have impacts on abundance of age-0 sport fish in other systems. The abundance of all sport fish species was stable or increasing in all reservoirs, except for walleye Sander vitreus (Mitchell) and white bass Morone chrysops (Rafinesque) in Lewis and Clark Lake. Age-0 white crappie was the most supported model for explaining age-0 walleye abundance in Lewis and Clark Lake, and adult white crappie abundance was the most supported model parameter for explaining age-0 white bass abundance in the reservoir. Findings of the current study highlight the need for species-specific management of both environmental (i.e. flow manipulation) and biological factors (i.e. harvest limits for sport fish) to increase the abundance of age-0 sport fish. Due to the dynamic nature of aquatic systems, resulting requirements for management agencies are system-specific evaluations and management approaches.

中文翻译：

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影响密苏里河四个干流水库中 0 龄运动鱼丰度的因素

评估了南达科他州四个主要密苏里河水库中八种运动鱼类的 0 龄鱼种丰度，以估计环境和生物因素对 0 龄鱼种丰度的影响。分析来自每个水库的数据集（至少连续十年）以评估月度（即测量高度、温度和降水）和年度（即冷却度日和加热度日、最低、平均和最高温度）的影响，以及平均降水量）环境和生物因素。生物因素，包括年龄 0 猎物鱼类的丰度（即沙丁鱼Dorosoma cepedianum[Leseuer] 丰度）、0 龄运动鱼丰度和成年运动鱼丰度进行了检查。包括已知会影响其他系统中 0 岁运动鱼丰度的因素。所有水库中所有运动鱼类的丰度都保持稳定或增加，除了大眼砂光鱼(Mitchell) 和白鲈Morone chrysops(Rafinesque) 在刘易斯和克拉克湖。0 岁白克拉皮鱼是解释 Lewis 和克拉克湖 0 岁白鲈丰度的最受支持的模型，而成年白克拉皮鱼丰度是解释储层中 0 岁白鲈丰度的最受支持的模型参数。当前研究的结果强调需要对环境（即流量操纵）和生物因素（即运动鱼的捕捞限制）进行特定物种管理，以增加 0 龄运动鱼的丰度。由于水生系统的动态特性，因此对管理机构的要求是针对特定系统的评估和管理方法。