Historical documentation of ichthyofaunal diversity in Northern and Northeastern Mexico.

Authors: Erick González, Paola Pérez-Valtierra

Year: 2025

Abstract

The North and Northeastern regions of Mexico include the states of Sonora, Durango, Chihuahua, Coahuila, Nuevo León, and Tamaulipas. This area encompasses six biogeographic provinces, highlighting its ecological, economic, and energy-related significance, with a complex territorial and environmental dynamic. Its main economic activities are mining, manufacturing, commerce, and various urban services. The region features a diversity of water systems, including rivers, aquifers, lagoons, and wetlands, although many of these face pressures from overexploitation and climate change. It relies heavily on underground aquifers, especially in arid zones such as Chihuahua, Coahuila, and northern Nuevo León. These extreme environmental conditions—particularly the lower number of freshwater bodies compared to central and southern Mexico—result in a biodiversity that is generally distinct from the rest of the country, especially regarding freshwater ecosystems. The Ichthyological Collection of the Universidad Autónoma de Nuevo León has recorded 209 species in Northern Mexico between 1966 and 2019. These species are distributed across 90 genera, 38 families, and 21 orders. Among the northern states, Tamaulipas is represented by 59 species, making it the state with the highest species richness; however, it is important to note that many of these species were recorded in Laguna Madre, Tamaulipas, so their affinity is not exclusively freshwater. The second most species-rich state is Chihuahua, with 56 species, followed by Coahuila with 39. Sonora is represented by only three species, mainly because most of the species recorded in that state are marine. The most represented orders in the northern states are Cypriniformes (29.6%) and Cyprinodontiformes (26.7%). The most represented families are Leuciscidae (21.8%), Poeciliidae (14.6%) and Cyprinodontidae (8.7%). Since 2020, the region has experienced significant hydrological changes, which may affect the ichthyological biodiversity of its water bodies. This underscores the need for ongoing monitoring and the development of ecological studies that provide specific and updated information to support more effective management strategies under various future scenarios.