Influence of environmental quality on the diet of Astyanax in a microbasin of central western Brazil

Abstract

ABSTRACT. This study analyzed physicochemical characteristics of the water, degradation of the surroundings and the influence of these factors on the diet of two fish species of Astyanax in Tarumã stream microbasin, central western Brazil. Fish were collected in eight sites between 2007 and 2010, using gillnets and sieves. Environmental variables were evaluated by a principal component analysis and the diet based on Spearman's correlation. The variables width, type of riparian vegetation, pH, conductivity, total dissolved solids, temperature, oxidation and reduction potential, presence of waste, and altitude have separated the sampling sites into two groups: 'less impacted' and 'more impacted'. The two characid species presented omnivorous habit, typical of disturbed environments. The consumption of food resources was different over the space: terrestrial plants and sediment were more important in the most impacted sites for both species. And specifically to Astyanax altiparanae the order of importance of the food was distinct between most and less impacted sites. These data indicated that the diet of these species is a suitable tool for analyzing the environmental quality of the studied sites.Keywords: environmental degradation, streams, ichthyofauna, food.Influência da qualidade ambiental na dieta de Astyanax em uma microbacia do CentroOeste do Brasil RESUMO. Este trabalho teve como objetivo analisar as características físico-químicas da água, degradação do entorno e a influência destes fatores na biologia alimentar de duas espécies de Astyanax na microbacia Touro-Tarumã, Centro-Oeste do Brasil. Os peixes foram coletados em oito locais, de 2007 a 2010, utilizando redes de espera e peneirões. As variáveis ambientais foram avaliadas por análise multivariada e a dieta pela correlação de Spearman. As variáveis ambientais largura, tipo de mata ciliar, pH, condutividade, sólidos totais dissolvidos, temperatura, potencial de oxidação e redução, presença de lixo e altitude permitiram diferenciar os locais de coleta em "mais impactados" e "menos impactados". As duas espécies de caracídeos estudadas apresentaram comportamento onívoro, que é típico de ambientes alterados. Os recursos alimentares consumidos pelas espécies diferiram espacialmente: vegetais terrestres e sedimento apresentaram maior importância nos locais mais impactados para as duas espécies. Especificamente para A. altiparanae a ordem de importância do alimento consumido diferiu entre os locais mais e menos impactados. Estes dados indicam que o estudo da dieta destas espécies mostrou-se uma ferramenta adequada para análise da qualidade ambiental destes locais.Palavras-chave: degradação ambiental, riachos, ictiofauna, alimentação.

Fourier transform-infrared photoacoustic spectroscopy applied in fish scales to access environmental integrity: A case study of Astyanax altiparanae species

“…Therefore, the availability of food depends on the condition of the environment in which the individual is inserted and this variation particularly occurs in species that have higher food plasticities, such as A. altiparanae [3,37]. Ibañez et al [20] stated that the morphology and chemical composition of fish scales can be adjusted by seasonal, location or habitat variability and also by availability and characteristics of food, leading to a differentiation of phenotypic characteristics.…”

“…This characteristic indicates that it can consume several food types, such as detritus/sediments, plants and insects. Souza and Lima-Junior [3] found in their study of the diet of A. altiparanae that food consumed by this species may differ based on the quality of the environment in which the species is inserted.…”

“…Because of their limited flow, they are strongly sensitive to anthropogenic actions [1,2]. In streams, the impacts of these actions lead to the loss of integrity in the ecosystem, which is commonly evaluated through water quality tests of the dissolved oxygen, pH, temperature, electrical conductivity and through the physical structure of the habitat [3]. However, in some cases, these parameters are not sufficient to evaluate the ecosystem integrity, indicating that the search for other biological indicators must be encouraged.…”

“…Among them, fishes are those of great interest, mainly because they bioaccumulate substances of the environment [5]. Different fish species (or their parts, such as scales) have been extensively explored at the literature as bioindicators [3,6]. It is well known that fish scales consist of different organic compounds, water and minerals, and they have two distinct faces: the so-called inside face, which is smooth, fibrillar and contains a higher concentration of collagen; and the outside face, which is bony and rough, and is composed of a single mineral phase of calcium deficient hydroxyapatite [7][8][9][10].…”

Ontogeny of feeding by Astyanax paris in streams of the Uruguay River Basin, Brazil

“…Protection of its habitats should consider not only the environmental quality of the streams, but also the integrity of adjacent riparian vegetation. The importance of riparian vegetation to fish diet is well recognized and documented for the allochthonous feeder Astyanax species (Gomiero and Braga, 2003;Borba et al, 2008;Ferreira et al, 2012;Souza and Lima-Junior, 2013;Silva et al, 2014;Leite et al, 2015). Conserving the streams is also important for those autochthonous feeders (Cavalheiro and Fialho, 2016).…”