Habitat use by Astyanax taeniatus (Jenyns, 1842) (Characiformes: Characidae) in a coastal stream from Southeast Brazil

Abstract

The habitat use of a stream-dwelling Astyanax taeniatus from the State of Rio de Janeiro was investigated. We performed 12 h of underwater observation in a 200 m long stretch in the upper Roncador stream and quantified the following microhabitat descriptors: (i) water velocity, (ii) distance from the stream bank, (iii) substratum, and (iv) water column depth. Microhabitat selectivity was analyzed by comparing the microhabitat used by fish and the microhabitat available in the study site as well as by applying the Ivlev Electivity Index to the microhabitat use data. Differences in the use and availability of the various microhabitats revealed non-stochastic patterns of spatial occupation by A. taeniatus, which was selective for two of the four analyzed microhabitats. Our findings indicated that A. taeniatus is associated with habitats that have higher depths, low water velocity, and sand and bedrock substratum.O uso do micro-habitat por Astyanax taeniatus de riacho do estado do Rio de Janeiro foi investigado. Realizamos 12 h de observações subaquáticas em um trecho de 200 m do alto rio Roncador e quantificamos os seguintes descritores do microhabitat: (i) velocidade da água, (ii) distância da margem, (iii) substrato, e (iv) profundidade da coluna d'água. A seletividade do micro-habitat foi analisada pela comparação do micro-habitat usado pelos peixes e o micro-habitat disponível na área de estudo, bem como pelo Índice de Eletividade de Ivlev aplicado aos dados de uso do micro-habitat. As diferenças no uso e disponibilidade dos diferentes descritores do micro-habitat revelaram um padrão não aleatório para a ocupação especial por A. taeniatus que foi seletivo para dois dentre quatro descritores analisados. Nossos registros indicaram que A. taeniatus está associado à habitats com maior profundidade, baixa velocidade da água e substrato de areia e rocha.

Feeding strategy and morphology as indicators of habitat use and coexistence of two loricariid fishes from a Brazilian coastal stream

“…Depth measurements were taken with metric rulers and water flow with a digital flow meter (Global Water FP101). Substrate types were classified as mud, sand, gravel, boulder and bedrock following Manna et al (2014). Proportion of each substrate type were calculated using quadrats of 20 cm 2 in the same five points along each transect.…”

Effect of body size on microhabitat preferences in stream-dwelling fishes

“…Although intraspecific variability has recently received more attention in ecological studies (de Bello et al., ; Violle et al., ), differences among individuals are still poorly represented in studies of fish communities (Blanck & Lamouroux, ; Brandl & Bellwood, ; Goldstein & Meador, ), being restricted to marine species (Hammerschlag‐Peyer & Layman, ; Pratchett et al., ). In freshwater fish communities, most knowledge on microhabitat use is descriptive (Leal et al., ; Manna et al., ; Mazzoni et al., ) and limited to population dynamics, i.e., data of one species (Bourke et al., ; Greenberg, Bergman, & Eklöv, ; Johnson, Ross, Dropkin, & Redell, ). Furthermore, the high plasticity of stream fish was frequently approached (Manna, Rezende, & Mazzoni, ; Meyer, ; Svanbäck & Persson, ; Ward, Webster, & Hart, ), which highlighted the importance of measuring the variation in ecological traits at the intraspecific level in freshwater communities.…”

“…The position of each quadrat along the transects was established as follows: (i) on the right shore, 10 cm from the bank; (ii) in the first third of the channel; (iii) in the second third of the channel; (iv) on the left shore, 10 cm from the bank. Thus, the microhabitat parameters measured were the distance from the nearest stream bank, water velocity, stream width, substrate type, water column depth, aquatic and terrestrial plant cover for each quadrat (availability of microhabitat resources) and each individual fish (microhabitat use; Table ; Manna et al., ; Mazzoni et al., ).…”

“…However, morphology as a predictor of fish ecology is more commonly used to explain the variability in feeding habits (Albertson, ) and not habitat use. In addition, habitat use on a small scale (i.e., microhabitat) has been poorly studied in stream‐dwelling fish assemblages (Beyer, Copp, & Gozlan, ; Manna, Rezende, & Mazzoni, ; Mazzoni, Novaes, & Iglesias‐Rios, ). To shed light on the relationship between morphology and habitat use, it is important to understand that particular characteristics such as stream depth, determine the amount of space available in the water column (Boavida, Santos, Pinheiro, & Ferreira, ).…”

Eco‐morphological attributes and feeding habits in coexisting characins

“…Coexistence may also result in distinct morphological adaptations that reflect different ways of exploiting the available resources (Labropoulou & Eleftheriou, ; Russo et al , ; Nandi & Saikia, ). The Characidae is one of the most diverse groups of Neotropical fishes, with a variety of body forms and behavioural strategies related to the exploitation of different microhabitats and environmental conditions (Manna et al , , ; Marques et al , ).…”