Diet and feeding ecology of non-native fishes in lentic and lotic freshwater habitats

Abstract

The Paranapanema River is most frequently invaded by non-native fish from the Upper Paraná River Freshwater Ecoregion. To understand how the diet of non-native fishes varies based on habitat type, we studied 12 populations of 6 non-native fish species with the aim of verifying whether diet, niche breadth, or trophic guild vary between lentic and lotic habitats. Fish were sampled in both habitats in the Paranapanema River basin between August 2014 and March 2016. A permutational multivariate analysis of variance – PERMANOVA was applied so that the composition of fish diet could be compared between habitats. Levin’s standardized index was used to evaluate the trophic niche breadth of the species, revealing differences in the diets of Ossancora eigenmanni, Auchenipterus osteomystax and Trachelyopterus galeatus based on habitats. Seven trophic guilds were identified, and those for Serrasalmus marginatus, Loricariichthys platymetopon, and T. galeatus were the same (piscivores, detritivores, and omnivores, respectively) in both habitats. In contrast, the trophic guilds of O. eigenmanni, A. osteomystax, and Plagioscion squamosissimus varied between the habitats. Habitat-specific variability in the diet composition of the species and, for the most, the niche breadth in the lotic habitats increased; therefore, we conclude that this type of environment can provide access to a greater variety of food resources for non-native fishes.