Fish diversity in the cascade of reservoirs along the Paranapanema River, southeast Brazil

Fernando Mayer Pelicice,Valter M Azevedo-Santos,Angelo Antonio Agostinho,Marlene Sofia Arcifa,André Luiz Henríques Esguícero

doi:10.1590/1982-0224-20170150

Abstract

ABSTRACT The Paranapanema River is a major tributary of the upper Paraná river basin. Eleven hydropower dams regulate its main course, but no study has investigated fish diversity in these impoundments at the basin-scale. The present study investigated spatial patterns of richness, composition, and abundance of native (non-migratory and migratory) and non-native fishes in the cascade of reservoirs along the Paranapanema River. The study is based on data collected from 34 independent studies conducted in nine reservoirs (47 samples). The compilation recorded 161 species, being 111 native (14 migratory) and 50 non-native. Total richness ranged between 56 and 112 species/reservoir, with a mean of 72 (49.9 non-migratory, 8.1 migratory and 14 non-native). The number of non-migratory species showed no spatial trend along the cascade system, but migratory and non-native richness increased toward downstream reaches. We also observed spatial variation in species composition along the cascade system, but some non-native fishes were widely distributed. Migratory fishes showed low relative abundance (usually < 10%), while non-native species were common and more abundant, especially in reservoirs downstream. Our results revealed a high diversity of fishes in the cascade of impoundments, but indicated that migratory fishes are rare, while non-native species are common or dominant.

Highlights

Hydropower dams affect the functioning of main rivers in South America (Agostinho et al, 2016), resulting in a number of negative impacts on biodiversity, especially fishes (Pringle et al, 2000; Agostinho et al, 2007a)
Eleven hydropower dams regulate the main course of the Paranapanema River, creating a cascade of impoundments along the entire river system
This information is important to guide management and conservation plans, since the Paranapanema basin is severely disturbed by different human activities, demanding specific actions to preserve fish diversity and fishing stocks

Summary

Introduction

Hydropower dams affect the functioning of main rivers in South America (Agostinho et al, 2016), resulting in a number of negative impacts on biodiversity, especially fishes (Pringle et al, 2000; Agostinho et al, 2007a). Studies that investigated fish diversity in these reservoirs (e.g., Barrella, Petrere Jr., 2003; Hoffmann et al, 2005; Duke Energy, 2008; Orsi, Britton, 2014; Santos et al, 2017; Garcia et al, 2018) indicated that assemblages are composed primarily of smallsized sedentary species, in addition to several non-native fishes. These studies, focused on specific impoundments; no study has investigated the whole cascade system, in order to provide a more complete picture about taxonomic diversity and abundance patterns. This information is important to guide management and conservation plans, since the Paranapanema basin is severely disturbed by different human activities (e.g., dams, agriculture, urbanization, aquaculture), demanding specific actions to preserve fish diversity and fishing stocks

Methods

Results

Conclusion