Ecologia e conservação de peixes da bacia do Rio Guareí, São Paulo, Brasil
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Data
2020-02-27
Autores
Azevedo-Santos, Valter Monteiro de [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
A bacia do Rio Guareí está situada dentro do sistema do Paranapanema (alto Paraná), em São Paulo, sudeste do Brasil. O primeiro estudo ictiológico dentro do seu perímetro, considerando peixes não fossilizados, ocorreu na década de 2000. Posteriormente, outros, poucos, ocorreram na região. Assim, esta tese foi idealizada com base nos déficits de estudos sobre peixes, e consequentemente de conhecimento, da bacia do Rio Guareí. O objetivo principal deste trabalho foi investigar a composição, a distribuição, a ecologia, e avaliar aspectos sobre a conservação da ictiofauna da bacia do Rio Guareí. O Capítulo 1 traz um levantamento — provavelmente o mais completo até agora — das espécies de peixes que foram encontradas no sistema. Foram capturadas um total de 50 espécies, a maioria nativa. Contudo, com base nos outros capítulos, a riqueza aumentou para 52 espécies; as quais foram inseridas em uma chave de identificação no Capítulo 1. No Capítulo 2, avaliou-se, sob abordagem espacial e funcional, a predação de piranhas sobre as espécies de peixes do Rio Guareí. Foram encontradas diferenças nas mutilações ao longo do corpo d’água. Além disso, peixes com os mais variados traços foram atacados. O Capítulo 3, assim como o anterior, tem como foco apenas o Rio Guareí. Foram amostrados três sítios e capturado um total de 19 táxons, considerando a identificação máxima (que foi de classe até espécie). Houve a captura de larvas de Prochilodus lineatus (migrador de longa distância), mas em baixas densidades — quando comparada com outros táxons. Por outro lado, não houve diferenças nas densidades de larvas e ovos ao longo do corpo d’água. Além disso, não foram obtidas diferenças na estrutura das larvas. Contudo, a análise da estrutura deve ser considerada com ressalva, basicamente porque foi realizada utilizando apenas famílias — dada as limitações na determinação de larvas ao nível de espécies. Ainda, são feitas avaliações sobre o papel do Rio Guareí na manutenção das populações, ou mesmo comunidades de peixes, do reservatório de qual é tributário (i.e., Jurumirim). No Capítulo 4, registra-se o primeiro caso de albinismo para espécie Cambeva guareiensis. Por fim, o Capítulo 5 traz relatos de organismos associados a peixes dos estudos anteriores. O conhecimento da ictiofauna da região, como aqui apresentado, tem implicações importantes para conservação e para realização de novos trabalhos científicos, de inúmeros escopos, na bacia do Rio Guareí.
The Guareí River basin is located within the Paranapanema system (upper Paraná), in São Paulo, southeastern Brazil. The first ichthyological study within its perimeter, considering non-fossilized fish, took place in the 2000s. Since then, a few others have been carried out in the region. Thus, this thesis was conceived based on the shortfalls of studies on fish and, consequently, of knowledge of the Guareí River basin. The main objective of the work was to investigate the composition, distribution, ecology, and to evaluate aspects of the conservation of the ichthyofauna from the Guareí River basin. Chapter 1 provides a survey — probably the most complete up to now — of the species of fish found in the system. Collections resulted in a total of 50 species, most of them native. However, based on the other chapters, the richness increased to 52 species; these are included in an identification key in Chapter 1. In Chapter 2, using a spatial and functional approach, the predation of piranhas on fish species of the Guareí River is evaluated. Differences were found in mutilations along the waterbody. In addition, fish with the most varied traits were attacked. Chapter 3, as the previous one, focuses only on the Guareí River. Three sites were sampled and a total of 19 taxa were captured, considering the maximum level of identification (from class to species). Larvae of Prochilodus lineatus (long-distance migrator) were collected, but at low densities when compared to other taxa. No differences in the densities of larvae and eggs along the waterbody were found. In addition, no differences in the structure of larvae were obtained. However, the analysis of the structure must be considered tentative, basically because it was performed using only families given the limitations in determining larvae at the species level. In addition, evaluations were performed on the role of the Guareí River in maintaining the fish populations, or even communities, of the Jurumirim reservoir. In Chapter 4, the first case of albinism for Cambeva guareiensis is registered. Lastly, 14 Chapter 5 provides reports of organisms associated with fish of previous studies. The knowledge of the ichthyofauna of the region, as presented herein, has important implications for conservation and for carrying out new scientific works, of wide-ranging scope, in the Guareí River basin.
The Guareí River basin is located within the Paranapanema system (upper Paraná), in São Paulo, southeastern Brazil. The first ichthyological study within its perimeter, considering non-fossilized fish, took place in the 2000s. Since then, a few others have been carried out in the region. Thus, this thesis was conceived based on the shortfalls of studies on fish and, consequently, of knowledge of the Guareí River basin. The main objective of the work was to investigate the composition, distribution, ecology, and to evaluate aspects of the conservation of the ichthyofauna from the Guareí River basin. Chapter 1 provides a survey — probably the most complete up to now — of the species of fish found in the system. Collections resulted in a total of 50 species, most of them native. However, based on the other chapters, the richness increased to 52 species; these are included in an identification key in Chapter 1. In Chapter 2, using a spatial and functional approach, the predation of piranhas on fish species of the Guareí River is evaluated. Differences were found in mutilations along the waterbody. In addition, fish with the most varied traits were attacked. Chapter 3, as the previous one, focuses only on the Guareí River. Three sites were sampled and a total of 19 taxa were captured, considering the maximum level of identification (from class to species). Larvae of Prochilodus lineatus (long-distance migrator) were collected, but at low densities when compared to other taxa. No differences in the densities of larvae and eggs along the waterbody were found. In addition, no differences in the structure of larvae were obtained. However, the analysis of the structure must be considered tentative, basically because it was performed using only families given the limitations in determining larvae at the species level. In addition, evaluations were performed on the role of the Guareí River in maintaining the fish populations, or even communities, of the Jurumirim reservoir. In Chapter 4, the first case of albinism for Cambeva guareiensis is registered. Lastly, 14 Chapter 5 provides reports of organisms associated with fish of previous studies. The knowledge of the ichthyofauna of the region, as presented herein, has important implications for conservation and for carrying out new scientific works, of wide-ranging scope, in the Guareí River basin.
Descrição
Palavras-chave
Bacia do Rio Paranapanema, Ictiofauna, Ictioplâncton, Neotrópico, Riachos