Feeding ecology of Pecos River fish assemblages

Authors: Chris Wilcut, Daniel Marquez, Jessica East, Allison Pease

Year: 2013 (xlv)

Abstract

In the Pecos River, fish assemblage structure changes along with considerable variation in physiography, water availability, salinity, and land use. The extent to which trophic resource use of fishes varies within the system is poorly understood. We examined the diets of fishes in twelve sites along the main stem of the Pecos River in New Mexico and Texas. We analyzed stomach contents in order to estimate the volume of prey items consumed by common Pecos fish species. Our analyses revealed differences in trophic resource use among species. Species such as Menidia beryllina consumed high proportions of aquatic insect larvae. Others were more omnivorous (e.g., Cyprinella lutrensis), consuming invertebrates as well as algae and detritus. Two non-native, coastal species, Fundulus grandis and Cyprinodon variegatus, had diets consisting largely of other fishes and detritus, respectively. Reaches with less degraded habitats supported greater fish species richness and the use of a more diverse array of prey items. A better understanding of the feeding ecology of Pecos River fishes is important for ecosystem management and restoration efforts.