Diet, reproduction and population structure of the introduced Amazonian fish Cichla piquiti (Perciformes: Cichlidae) in the Cachoeira Dourada reservoir (Paranaíba River, central Brazil)

Tatiane Ferraz Luiz,Jorge Luiz Rodrigues Filho,André Moldenhauer Peret,Alberto Carvalho Peret,Marcela Roquetti Velludo

doi:10.15517/rbt.v0i0.3135

Abstract

The Blue Peacock Bass (Cichla piquiti), native to the Tocantins-Araguaia river basin of the Amazon system, was introduced into the basin of the Paranaíba River, Paraná River system. Cachoeira Dourada reservoir is one of a series of dams on the Paranaíba River in central Brazil, where this fish has become established. A study of its feeding spectrum, combined with information about its reproductive characteristics and population structure, would enable the current state of this species in the reservoir to be assessed and might provide useful data for the management of other species native to this habitat. This study showed that the peacock bass has no predators or natural competitors in the reservoir and that reproduces continuously, with high reproductive rates, and has a smaller median length at first maturity (L50) than other species of Cichla. Its successful establishment in habitats strongly affected by human activity should cause changes in the whole structure of the local fish communities. Nonetheless, in this reservoir, there appears to be some sharing of the functions of this species with native carnivorous fish, a situation that may be sustained by the presence of a wide variety of foraging fish.

Highlights

The introduction of non-native species into new habitats is the second biggest cause of species extinctions, the first being disappearance of the habitats themselves (Simberloff 2003)
The potential for a successful invasion is determined by the properties of the invading species, such as its tolerance of widely different environmental conditions, dispersion and fast colonization of the habitat, aggressiveness, competitiveness and high reproductive rate (Grime 1979), by its value to the fishing industry (Moyle et al.1986), and by the characteristics of the local species, namely their competitiveness and capacity to resist, and of the community being invaded (Sakai et al 2001)
The blue peacock fish is widely established in the reservoirs of the Paraná River basin in the Brazilian states of Minas Gerais and São Paulo, including the basin of the Paranaíba (Kullander & Ferreira 2006)

Summary

Introduction

The introduction of non-native species into new habitats is the second biggest cause of species extinctions, the first being disappearance of the habitats themselves (Simberloff 2003). The blue peacock bass (locally known as tucunaré), Cichla piquiti Kullander & Ferreira, 2006, occurs naturally in the drainage basin of the Tocantins and Araguaia Rivers (Kullander & Ferreira 2006) In these floodplain ecosystems, the trophic relations of fish communities are affected by a number of factors, such as the properties of the surrounding ecosystem, the feeding flexibility of the species and the effects of seasonal variation on the availability of food resources. The blue peacock fish is widely established in the reservoirs of the Paraná River basin in the Brazilian states of Minas Gerais and São Paulo, including the basin of the Paranaíba (Kullander & Ferreira 2006) Several dams in this system lead to changes in its physical, chemical and biological attributes, greatly modifying the biotic interactions and resulting in a simplified ecosystem (Agostinho & Zallewski 1995). A study of the feeding spectrum of Cichla piquiti in the Cachoeira Dourada reservoir on the Paranaíba River, along with the data on its reproductive features and population structure, would contribute towards an assessment of the current state of this cichlid in the habitat and provide information that could be used in the management of other exotic invaders

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Conclusion