Abstract
ABSTRACT This study evaluated gills and liver of Astyanax bifasciatus as histological biomarkers for biomonitoring of streams along areas with different land uses. The fish were collected by electrofishing in six streams in the basin of the lower Iguaçu River. The objective was to correlate the presence and degree of histopathological alterations of gills and liver with the environmental variables among streams along different land uses. The low frequency of histopathological alterations found in fish from the forest streams suggested normal organ functioning. In fish from the rural and urban streams, the histopathological alterations occurred were in higher frequency, indicated light to moderate damage in gills and liver of fish from the rural streams, and moderate to severe damage in liver of fish from urban streams. The histopathological alterations in gills (lamellar aneurysm) and livers (vascular congestion) verified in impacted streams were significantly more frequent and severe. It was possible to distinguish streams along different land uses, suggesting that these histopathological alterations can be used as biomarkers for biomonitoring studies. The health integrity of fish from streams in forest areas further reinforces the importance of maintaining preservation areas in basins under intensive land use.
Highlights
The watersheds in Brazil are characterized by an immense network of small water courses, with different physiographic characteristics, which promotes the occurrence of a high diversity of organisms (Nogueira et al, 2010)
The general structure of the gills of Astyanax bifasciatus is formed by branchial arches arranged laterally in an oropharyngeal cavity protected by the operculum, where gas exchange occurs
Lamellar aneurysm and mitochondria-rich cells (MRC) hyperplasia were frequent in fish of the rural and urban streams (Figs. 2c, h), followed by lamellar hyperplasia and mucous cells hyperplasia in fish from urban stream 2 (U2) (Figs. 2d, e, h)
Summary
The watersheds in Brazil are characterized by an immense network of small water courses, with different physiographic characteristics, which promotes the occurrence of a high diversity of organisms (Nogueira et al, 2010). Except for a few areas of the Amazon Region, all Brazilian basins are subjected to some of the main impacts on the freshwater ecosystems, considered global, such as habitat destruction, pollution, flow modification, and introduction of non-native species (Agostinho et al, 2005). In this scenario, the south and southeast regions, on the basis of higher densities of population and economic development, e170129[1]. An example of this situation is the Iguaçu River in Paraná State, considered the second most polluted river in Brazil (IBGE, 2015)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
