" Fishes are the most diverse group of vertebrates with 36,179 valid species, of which 45% of them are freshwater fishes. This freshwater fish diversity is extraordinary considering that they only occupy 0.02% of the aquatic habitat. However, their ecosystems have been under a strong human pressure which has intensified in the last decades. Nearly 83% of the freshwater habitats worldwide show some impact, which have resulted in the drastic decline in freshwater fish species. Among the most important threats are habitat loss, water pollution, and introduction of non-native species. Mexico harbors more than 600 species of which 264 are endemic (43%), and nearly 30% are threatened due to human impact. The conservation status for the Mexican ichthyofauna is worrying due to the recent assessment by the IUCN that showed that 165 species are classified under some category of threat. In the present chapter we describe the Global and Mexican freshwater diversity, and the major threats for their conservation. Additionally, we selected three ecoregions: (1) Cuatro Cienegas, (2) Lerma River, and (3) Grijalva River, based on both their diversity and contrasting differences in anthropic pressures, to assess the effect that the human footprint has had on its fish diversity and their threats. Our results showed that all sites had high percentages of threatened freshwater fish species, the Lerma River with 63.6%, Grijalva River with 59.8%, and Cuatro Cienegas with 42.9% threatened species. Regarding the human footprint on these ecoregions, Cuatro Cienegas showed the least human modification; however, 46.88% of the native fish and 18.75% of its threatened fish species occur in degraded sites. Grijalva and Lerma Rivers had a similar area and percentage of human modification, but for the Lerma River, 92% of native fish and 72.67% of its threatened fish species occur in degraded sites. Based on our results and analysis, we provide some recommendations for filling important research gaps and proposed conservation strategies for the freshwater fish fauna of Mexico "
Beltrán-López, Rosa Gabriela & Ana Berenice García-Andrade, C. Patricia Ornelas-García. 2023. "Mexican Freshwater Fishes in the Anthropocene". Mexican Fauna in the Anthropocene. (7):129–152. DOI: 10.1007/978-3-031-17277-9_7 (ffm01214) (abstract)