Functional assessment approaches can identify indicators of environmental change and ecological response in estuaries. This study used a 24-year coastal fisheries dataset (1993–2016) and environmental data to evaluate fish assemblage changes in Galveston Bay, Texas (USA) in response to environmental parameters and freshwater inflows, drought, and flood. Functional classification categorized 107 fish species into eleven functional groups to determine if estuarine species serve as suitable indicators of environmental condition. Nonmetric multidimensional scaling (nMDS), distance-based linear models, and graphing techniques using annual departures from period averages determined relationships between functional group abundance, freshwater inflows, and environmental parameters. Results show that estuarine-resident carnivore, estuarine-resident omnivore, marine migrant carnivore, and marine straggler carnivore functional groups exhibit highest species richness (mean = 21 species) and abundance (mean = 48,411 individuals) compared with other functional groups (mean species richness = 3; mean abundance = 1143 individuals). Declines in abundance of functional groups occurred during a 2011–2014 drought, with rebounds in 2015–2016. Relationships between inflows, salinity, and functional group abundance were evident in upper Galveston Bay, diminishing with increasing distance from major freshwater sources. Functional abundance in lower parts of the bay was decoupled from inflows and salinity changes. Findings support the conclusion that estuarine-resident and marine functional groups have limited potential to serve as bioindicators, while freshwater migrant carnivores are potential bioindicators for upper portions of the estuary. Functional methodologies provide insight into effects of environmental change on estuarine ecosystems and serve as management tools to assess changes in fish assemblages.

功能评估方法可以确定河口环境变化和生态响应的指标。这项研究使用了一个为期24年的沿海渔业数据集（1993-2016年）和环境数据来评估美国得克萨斯州加尔维斯顿湾的鱼类组成变化，以响应环境参数和淡水流入，干旱和洪水的影响。功能分类将107种鱼类分为11个功能组，以确定河口物种是否可作为环境状况的合适指标。非度量多维标度（nMDS），基于距离的线性模型以及使用距周期平均值的年度偏离的绘图技术确定了功能组含量，淡水流入量和环境参数之间的关系。结果表明，河口居民食肉动物 与其他功能组（平均物种丰富度= 3；平均丰富度= 1143个人）相比，居住在河口的杂食动物，海洋迁徙食肉动物和海洋随行食肉动物功能组的物种丰富度最高（平均= 21种），并且物种丰富度（平均= 48,411个个体）。 ）。在2011-2014年的干旱期间，功能人群的数量下降，而在2015-2016年则出现反弹。在加尔维斯顿湾上游，流入量，盐度和官能团丰度之间的关系很明显，并随着与主要淡水源距离的增加而减小。海湾下部的功能丰富度与流入量和盐度变化不相关。研究结果支持这样的结论，即居住在河口的地区和海洋功能团体具有作为生物指示剂的潜力有限，淡水迁徙食肉动物是河口上部的潜在生物指标。功能方法学可洞察环境变化对河口生态系统的影响，并用作评估鱼类组合变化的管理工具。