Natural flow regimes are an essential component of healthy fluvial systems, but hydropower production alters flow components, disrupting natural processes and impacting species reliant on them. Establishing improved management of flow regimes requires a better understanding of how fish respond to altered flow components, such as flow magnitude. We recently conducted a systematic map to provide a summary of the existing literature base on the impacts of flow regime changes on direct outcomes of freshwater or estuarine fish productivity. Of those studies considering the impacts of flow magnitude changes due to hydropower, studies on fish abundance, biomass and diversity responses were identified as subtopics (i.e., knowledge clusters) that had sufficient coverage for further review. This systematic review proposes to estimate how fish abundance, biomass and diversity are affected by alterations in flow magnitude due to hydropower production. This systematic review will use evidence identified during a systematic map process. An updated English language search will be performed using six bibliographic databases, Google Scholar, and networking tools to include academic and grey literature published after 2016. Eligibility screening will be conducted at two stages: (1) title and abstract, and (2) full-text. We will include all studies that evaluate the impact of changes to (or manipulations of) flow magnitude due to hydropower on fish abundance, density, biomass, yield, species richness, composition or diversity indices. The focus of this review will be on the downstream fluvial effects of flow magnitude changes and include hydroelectric facilities where water moves via gravity or by active pumping. Any freshwater or estuarine fish species or species group in temperate regions will be considered. Included eligible studies will undergo a critical appraisal that will assess the internal study validity. We will extract information on study characteristics, intervention/exposure and comparator details, measured outcomes, and effect modifiers. A narrative synthesis will describe the quantity and characteristics of available evidence, and where sufficient numbers of similar studies are available, meta-analysis will be conducted to estimate an overall mean and variance of effect.

中文翻译：

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由于水力发电而引起的流量变化如何影响温带地区鱼类的丰度和多样性？系统的审查协议

自然流态是健康河流系统的重要组成部分，但是水力发电会改变流态，破坏自然过程并影响依赖它们的物种。建立对流态的改进管理需要更好地了解鱼类对变化的流分量（例如流大小）的反应。我们最近进行了系统的地图绘制，以总结现有文献的基础，该文献基于流动状态变化对淡水或河口鱼类生产力的直接结果的影响。在那些考虑水力发电流量变化影响的研究中，关于鱼类丰度，生物量和多样性响应的研究被确定为子主题（即知识群），具有足够的覆盖面，需要进一步审查。这项系统的评估建议估算鱼类的丰度，水力发电产生的流量变化会影响生物量和生物多样性。该系统评价将使用在系统地图过程中确定的证据。将使用六个书目数据库，Google Scholar和网络工具进行更新的英语搜索，以包括2016年以后出版的学术和灰色文献。资格筛选将分两个阶段进行：（1）标题和摘要，以及（2）全文-文本。我们将包括所有评估因水电而引起的流量变化（或操纵）变化对鱼类丰度，密度，生物量，产量，物种丰富度，组成或多样性指数的影响的研究。这次审查的重点将放在流量变化对下游的河流影响上，包括水通过重力或主动泵送而流动的水力发电设施。在温带地区将考虑任何淡水或河口鱼类物种或物种组。纳入的合格研究将接受评估，以评估内部研究的有效性。我们将提取有关研究特征，干预/暴露和比较者详细信息，测得的结果以及效果修饰符的信息。叙述性综合将描述可用证据的数量和特征，并且在有足够数量的相似研究可用的地方，将进行荟萃分析以估计总体均值和效应方差。在温带地区将考虑任何淡水或河口鱼类物种或物种组。纳入的合格研究将接受评估，以评估内部研究的有效性。我们将提取有关研究特征，干预/暴露和比较者详细信息，测得的结果以及效果修饰符的信息。叙述性综合将描述可用证据的数量和特征，并且在有足够数量的相似研究可用的地方，将进行荟萃分析以估计总体均值和效应方差。在温带地区将考虑任何淡水或河口鱼类物种或物种组。纳入的合格研究将接受评估，以评估内部研究的有效性。我们将提取有关研究特征，干预/接触和比较者详细信息，测得的结果以及效果修饰剂的信息。叙述性综合将描述可用证据的数量和特征，并且在有足够数量的相似研究可用的地方，将进行荟萃分析以估计总体均值和效应方差。