Environmental factors associated with fish assemblage patterns in a high gradient river of the Gulf of Mexico slope


  • Norman Mercado-Silva
  • John Lyons
  • Edmundo Díaz-Pardo
  • Saúl Navarrete
  • Altagracia Gutiérrez-Hernández



Palabras clave:

Veracruz, fish community, Mexican rivers, La Antigua River, ecological gradients


Using multivariate analyses of fish community and environmental data, we explored associations among
13 fish species and 9 ecological guilds and identified ecological gradients that explain patterns in the fish community
of the La Antigua River (Veracruz, Mexico). Altitude, distance to ocean, stream width, and water temperature were
the most important variables explaining community composition. Sites with high altitudes (> 1 393 m), cold water
(< 17ºC), located far from the ocean (> 100 km) and less than 5 m wide were dominated by non-native Onchorhynchus
mykiss. Many sites exclusively inhabited by native poeciliids were also narrow (< 2 m), but were located at intermediate
altitudes (1 039-1 400 m) and distances to the ocean (> 80 km, < 100 km) and had warmer water temperatures (> 20ºC).
Because 7 guilds were exclusive to a single species, results from the guild analysis were very similar to species-specific
analyses. Higher species and guild diversity were found in wider sites (> 5 m), sites with lower altitudes (< 600 m),
and sites closer to the ocean (< 71 km). Variables related to human influence did not explain trends found in the fish