The Taquari River as area of reproduction and recruitment of fish and its role in biodiversity maintenance of the Jurumirim Reservoir (Upper Rio Paranapanema, SP)

Abstract

The Neotropical aquatic environment has been historically impacted, with severe effects upon fish fauna. The dams made for the construction of power plant cause the interruption of migratory routes and, furthermore, alter the natural hydrological regime, interfering as well in the perception of the environmental triggers. Thus, these dams are considered one of the strongest impacting ways upon species that need to perform large migrations, which seriously affects their populations causing depletion of fish stock. However, some studies relate species migratory capacity with the use of tributaries of large dams as spawning sites, which relatively solves the inherent problem. Hence, the objective of this project is to evaluate the reproductive dynamic of the ichthyofauna of the Taquari River, one of the formers of Jurumirim dam. Absence of ichthyofaunistic data in this important tributary, a pilot survey showed that this tributary may be an important reproductive site of migratory fishes remaining of the impact of the dam and that are commonly explored by artisanal and sportive fishery. To attend this aim, samplings will be carried out in three stretches of the tributary (high, middle and low) and in the dam area (lentic stretch) during two reproductive cycles 2011/2012 e 2012/2013. The fishes will be collected with several equipment (gill nets, beach seine and sieve). In the same stretches it will be collected eggs, fishes larvae and juvenile in order to evaluate the occurrence of spawning and recruitment in this area. The size, weight, sex and gonadal maturation stage will be inferred from the fishes sampled. To interpret the data, some biological reproductive variables of fish assemblages, like reproductive index, populacional structure, abundance and presence/absence of eggs, larvae and juvenile of fishes. It is expected to generate basis for environmental management this important tributary of Paranapanema river focusing on the maintenance of fishing resources and defining its role in the migratory route alternative. (AU)