Data from: Global patterns and gaps in research on salinity tolerance of inland fishes

Freshwater salinization is an emerging threat impacting one-third of the world's freshwater bodies. However, the salinity tolerance of many inland fishes remains understudied, despite being a crucial factor in determining species distributions and fitness. We analyzed a global database of experimental salinity tolerance of inland fishes, compiled from 128 sources, to investigate geographical and taxonomic biases. Additionally, we examined how salinity tolerance relates to fish traits and how experimental data align with field-reported salinity levels..Experimental data on salinity tolerance was available for less than 1% of the world’s inland fishes, with data severely lacking from diverse tropical regions and orders such as Siluriformes. Most studies focused on relatively large and widely distributed species from North America, Europe and Oceania. Our results showed that fish salinity tolerance was strongly associated with fish habitat type, taxonomy, aspects of morphology, migratory behaviour and the experimental approach used (direct vs. gradual). Our results also showed significant, though sometimes weak relationships between field-reported salinity levels and experimental estimates. Overall, maximum salinities reported for habitats occupied by inland fishes were lower than experimentally-estimated tolerances.Improved understanding of fish salinity tolerance will be essential for assessing impacts of freshwater salinization and forecasting the invasion potential of non-native species.淡水盐化是一种新兴威胁，正影响着全球三分之一的淡水水体。然而，尽管盐度耐受度是决定物种分布与适合度的关键因素，目前对多数内陆鱼类的盐度耐受度研究仍十分匮乏。我们整合了来自128项来源的全球内陆鱼类实验盐度耐受度数据库，以探究其地理与分类学偏差。此外，我们还分析了盐度耐受度与鱼类性状的关联，以及实验数据与野外实测盐度水平的匹配程度。全球内陆鱼类中仅有不足1%的物种拥有盐度耐受度实验数据，且热带多样区域及鲇形目（Siluriformes）等类群的数据严重缺失。多数研究聚焦于北美、欧洲及大洋洲体型相对较大且分布广泛的物种。研究结果表明，鱼类盐度耐受度与鱼类栖息地类型、分类学地位、形态特征、洄游行为以及所采用的实验方法（直接法 vs 逐步法）密切相关。同时，野外实测盐度水平与实验估算值之间存在显著（尽管部分关联较弱）的相关性。总体而言，内陆鱼类栖息生境的最高盐度报告值低于实验测得的耐受上限。进一步加深对鱼类盐度耐受度的认知，对于评估淡水盐化的影响以及预测外来物种的入侵潜力至关重要。