Riverine environments have been threatened by anthropogenic perturbations worldwide, whereby their fish assemblages have been modified by habitat changes and nonendemic species invasions. We assessed changes in fish assemblages by comparing the species presence in historical and contemporary fish data in the Yellow River from 1965 to 2015. The temporal change in species assemblages was found with increased nonendemic species and fewer natives. Fish species richness of the river declined 35.4% over the past fifty years. Moreover, the decreased mean Bray–Curtis dissimilarity among reaches suggested that the fish assemblages of different reaches in the Yellow River were becoming more similar over time. However, temporal patterns of fish assemblages varied among reaches. In the upper Yellow River, higher species richness and more invasive species were found than those in the historical record, while the lower reaches experienced significant species loss. Dam constructions, exotic fish invasions, and flow reductions played the vital role in structuring the temporal fish assemblages in the Yellow River. It is suggested that river basins which experienced different types and levels of stressors by anthropogenic perturbations can produce varied effects on their temporal trends of species assemblages.

Length-weight (LWRs) and length-length relationships (LLRs) were estimated for four important endemic fish species representating two genera and one family from the upper Yellow River in the Tibetan Plateau, China. Three of the species are endemic to the Tibetan Plateau, and the fourth is endemic to the Yellow River. The b values of all species were within expected ranges, varying between 2.54 and 3.33. The LLRs were highly correlated. The data of the four species represent the first description of their length-weight and length-length relationships.

Summary Length–weight relationships (LWRs) were estimated for 15 fish species representating 15 genera and six families from the Hunan Hupingshan National Nature Reserve, China. Six species are endemic to China, one of which is also endemic to the Yangtze River. The b values of all species were within the expected ranges, varying between 2.68 and 3.26. Data of 11 species represent the first description of LWRs and nine species have new records of maximum length.

1. The valley of Cuatro Ciénegas in Coahuila, Mexico, has the highest degree of local endemism of any habitat in North America. Despite the arid desert climate, the basin harbours an extensive system of permanent streams, wetlands, and springfed pools, and is divided into two sub-basins by the central Sierra de San Marcos y Pinos.2. Microsatellite loci were surveyed to infer the genetic diversity and population structure of Gambusia marshi, a poeciliid fish endemic to the Cuatro Ciénegas basin and the Río Salado de Nadadores in north-east Mexico.3. Bayesian clustering analysis revealed four genetic populations within G. marshi and a major east-west division corresponding to the Sierra de San Marcos y Pinos.

Length‐weight (LWRs) and length–length relationships (LLRs) were estimated for three native and one non‐endemic fish species, representating three families and four genera from four sites in the Tibetan Plateau, China. Specimens were caught by a gill net (mesh size: 1‐inch), cast net (mesh size 1–2 cm; depth: 1–2 m) and a traditional shrimp coop during July 2006, and from July 2013 to August 2014. The LWRs b‐values of all fish species ranged from 2.63 to 3.29. All correlation coefficient values were higher than 0.95. Their LLRs were highly correlated.