Composition and Diversity of Ichthyofauna in natural and artificial lacustrine environments in Southeast Brazil

Reinaldo Jose Castro

Resumo


Aim: The composition and diversity of fish in two lentic environments, a lagoon connected to the river and an artificial reservoir were determined in the dry and rainy periods of 2015. We expected to find more diversity in the connected lagoon and greater abundance in the reservoir. Methods: Specimens were caught using gillnetting and creels for sampling and environmental parameters such as temperature, electrical conductivity, pH, dissolved oxygen and water transparency were measured during the periods. Results: 622 specimens were collected from the following orders: Characiformes, Siluriformes, Perciformes and Gymnotiformes, from 9 families, 13 genera and 17 species. Pimelodus maculatus was the most abundant species in the lagoon. Two species were caught from the reservoir, Geophagus brasiliensis and Hoplias malabaricus, the former being predominant. The dominant species in the studied environments corresponded to 45.34% of the total number of specimens. The ichthyofaunal composition from the lagoon showed a high richness of the order Characiformes (70.59%). Siluriformes and Gymnotiformes represented 11.76% each and the order Perciformes only 5.88% of the total number of species. In the shallow reservoir, there was an equivalent contribution of Perciformes and Characiformes. The diversity was higher in the lagoon (H' = 2.27) and lower in the reservoir (H' = 0.31). Significant differences (p<0.05) of diversity were found between the periods (dry and rainy) in the connected lagoon. The catch of fish was lower in the dry season (37.78%) than the rainy season (62.22%). The principal component analysis (PCA) separated the environments and periods by the difference in water electrical conductivity. The prevalence of species of the orders Characiformes and Siluriformes follows the pattern found for the ichthyofauna in the Neotropical region. Conclusions: The distinct pattern of diversity and abundance of the ichthyofauna from the studied environments proved the hypothesis that the environment connected to the river presents high diversity when compared to the reservoir. The presence of aquatic macrophytes of different species acts as a preponderant factor in structuring the fish community of the lagoon connected to the river.

Palavras-chave


Ichthyofauna; abundance; connected lagoon; shallow reservoir; river.

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