Abstract
The objective of this study was to evaluate the effect of Oreochromis niloticus cage culture promoted variations in the δ13C and δ15N in Corbicula fluminea (Mollusca; Bivalvia) and in the sediment of an aquatic food web. Samples were taken before and after net cage installation in the Rosana Reservoir (Paranapanema River, PR-SP). Samples of specimens of the bivalve filterer C. fluminea and samples of sediment were collected using a modified Petersen grab. All samples were dried in an oven (60 °C) for 72 hours, macerated to obtain homogenous fine powders and sent for carbon (δ13C) and nitrogen (δ15N) isotopic value analysis in a mass spectrometer. There were significant differences in the δ13C and δ15N values of the invertebrate C. fluminea between the beginning and the end of the experiment. There were no differences between the δ13C and δ15N values of sediment. These results indicate that the installation of fish cage culture promoted impacts in the isotopic composition of the aquatic food web organisms, which could exert influence over the native species and the ecosystem.
Highlights
IntroductionSome reservoirs have been used for fish farming using net cages
In recent years, some reservoirs have been used for fish farming using net cages
There were no differences between the d13C values of sediment (Figure 2)
Summary
Some reservoirs have been used for fish farming using net cages. This activity has been growing on a large scale in Brazil (Agostinho et al, 2007). Several studies have shown that the installation of fish cage cultures promotes changes, of varying intensity, to the environment due to the eutrophication processes that they generate (Tundisi and Henry, 1986; Agostinho et al, 2007), causing variations in the quantity and availability of food in the ecosystem (Strictar-Pereira et al, 2010).
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