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In this study, it was examined the reproductive biology of Astyanax. altiparanae, in streams with different levels of environmental disturbance in the Ivinhema river basin (Mato Grosso do Sul State, Brazil). Samplings were conducted between July 2001 and November 2011, at 101 sites, using sieves, seining nets, gill nets and electrofishing. Streams were classified into three levels of environmental integrity. We analyzed 735 specimens, 410 females and 325 males. Females predominated in impacted streams and both sexes presented nearly the same pattern of length distribution in the three levels of environmental integrity. Females reached gonadal maturity with greater lengths (L 50 = 55.67mm) in altered and impacted streams and had higher reproductive activity between October and December. The species showed higher Condition Factor and higher reproductive intensity in the impacted streams. Our results evidenced that in impacted sites the species exhibited a good ability to allocate a significant portion of its energy to reproduction, probably due to the greater supply of food.

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The streams and rivers of the Upper Paraná River Basin have been seriously affected by impacts of high population density around the basin area. Fishes are widely used as models to assess the health of aquatic ecosystems, being considered as bioindicators of environmental pollution. In this context, our objective was to assess the potential genotoxic and mutagenic effects of the polluted water in three native fish species (Astyanax lacustris, Hypostomus ancistroides, and Rhamdia quelen) from Tarumã Microbasin, Upper Paraná River, Brazil. We also investigated the concentration of metals in water and in fish muscle to verify bioavailability and bioaccumulation of metals. For both less impacted sites (LI) and impacted sites (IMP) of the microbasin, the concentrations of metals were above the maximum limit allowed by Brazilian legislation (Resolution CONAMA 357/2005), except for Pb, total Cr, and Cu at LI sites and total Cr at IMP sites. A. lacustris showed a higher frequency of micronuclei (MN) at IMP sites compared with LI sites (p < 0.0001). We found no significant differences in MN frequency between site classes for H. ancistroides and R. quelen (p > 0.05). There were no significant differences between site classes regarding to nuclear abnormalities in erythrocytes frequencies (p > 0.05). A. lacustris from IMP sites had higher concentrations of Pb, Cu, Fe, Zn, and Ni in muscle tissue (p < 0.05), whereas H. ancistroides from IMP sites had higher concentration of Cr, Cu, and Ni (p < 0.0001) and R. quelen showed higher concentration of Cd, Fe, and Ni at these sites (p < 0.0001). So, the chosen biomarkers are able to identify the environmental risk of the water pollution.

In the present study, we evaluated the effects of biological factors, lifestyle factors, and environmental conditions on the induction of DNA damage in exfoliated cells of the oral mucosa. Age, sex, medication use, and environmental conditions were analyzed in individuals residing in the cities of Caarapó and Itaporã. The individuals were assessed by a questionnaire, and oral mucosa cells were collected and subjected to mutagenicity analysis. We observed no statistical differences in DNA damage related to sex. However, the mutagenic effect was found to be proportional to age, with higher frequencies of DNA damage observed in individuals between the ages of 46 and 65 years. In addition, higher frequencies of DNA damage were found in individuals who continuously used medication and for prolonged periods, and greater DNA damage was observed in individuals who used antihypertensive drugs than those who took antidepressants. In terms of environmental conditions, Caarapó residents had a significantly higher frequency of DNA damage than that of residents from Itaporã. Based on the analysis of land use and occupation, this result can be attributed to the smaller fraction of forest fragments and the higher proportion of buildings in Caarapó than Itaporã. We concluded that age, continued medication use, and environmental conditions can lead to greater DNA damage.

ABSTRACT. This study aimed at analyzing the influence of different levels of environmental integrity of streams of the Ivinhema river basin (Mato Grosso do Sul State, Brazil) on the diet of A. altiparanae. Samplings were performed from July 2001 to November 2011 at 101 sites, using sieves, seining and gill nets, and electrofishing. Streams were classified into three levels of environmental integrity. We analyzed 664 stomachs with the methods of frequency of occurrence and volumetric analysis index, combined in the Importance Index (AI). The species was omnivorous, with predominance of allochthonous resources. At the least impacted sites, the most representative resource was allochthonous plant material; and in the altered sites in the rainy period the most consumed item was allochthonous arthropods. On the other hand, at the most impacted sites in the dry period there was a lower consumption of allochthonous plant material and allochthonous arthropods, compared with other levels of environmental integrity considered, with higher consumption of autochthonous arthropods. The results evidenced that in the least impacted sites there was greater contribution from allochthonous resources, probably because these environments show a more preserved riparian forest.

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