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Given the importance of fish movement to the dynamics and maintenance of stream dwelling fish communities from the Atlantic Forest, we analysed patterns of fish movement in a coastal stream from Southeastern Brazil, using mark-recapture technique. Displacement distance of each species were presented and discussed considering seasonal (rainy and dry) and body size patterns. We marked 10 species along the stream and recaptured 440 (34.6%) of the 1,270 marked fishes. The species with significant number of upstream moving individuals were Astyanax janeiroensis, Characidium interruptum, Astyanax hastatus, Parotocinclus maculicauda and Awaous tajasica. Only Pimelodella lateristriga presented significant differences between resident and moving individuals. Characidium interruptum and A. tajasica demonstrated greater downstream and upstream movement, respectively, moving up to 2,100 m. Even after controlling for species identity we found no significant correlation between fish length and individual displacement distance. Fishes moved longer distances during the rainy season, in accordance to the breeding season. Patterns of fish movement were in agreement to life-history traits of many of the studied species and can be reflecting specific behaviour and morphologies. RESUMO Considerando-se a importância do movimento de peixes para a dinâmica e manutenção das comunidades de peixes de riachos da mata Atlântica, nós analisamos os padrões de movimento de peixes de um riacho costeiro do sudeste do Brasil, usando a técnica da marcação e recaptura. Avaliamos a distância do deslocamento de cada espécie e também se os padrões de movimento apresentavam alguma relação com a estação do ano (chuva e seca) e o tamanho do corpo. Marcamos 10 espécies ao longo do riacho e recapturamos 400 (34.6%) dos 1.270 peixes marcados. As espécies com número significativo de indivíduos se movendo para cima foram Astyanax janeiroensis, Characidium interruptum, Astyanax hastatus, Parotocinclus maculicauda e Awaous tajasica. Apenas Pimelodella lateristriga apresentou diferenças significativas entre os indivíduos residentes e em movimento. Characidium interruptum e A. tajasica foram as espécies com maior movimento tanto para baixo como para cima, respectivamente, se movendo até mais de 2.100 m. Mesmo após controlar a identidade das espécies, não registramos correlação significativa entre o comprimento e a distância individual do deslocamento. Registramos maiores densidades de peixes se movendo para montante durante a época de chuvas, em coincidência com a estação reprodutiva. Os padrões de movimento registrados estão de acordo com os componentes da história de vida de várias das espécies estudadas, e podem estar refletindo componentes morfológicos e comportamentais específicos.

The identification of mechanisms of spatial-temporal variation, obtained from the quantification of natural populations, is a central topic of ecological research. Despite its importance to life-history theory, as well as to conservation and management of natural populations, no studies concerning movement patterns and home range of small stream-dwelling fishes from Brazilian rain forests are known. In the present study we aimed to describe the longitudinal pattern of long distance movement as well as local patterns of short movement (daily home-range) of fishes from a Mata Atlântica stream from Southeast Brazil. We gathered information about movement dynamic in order to discuss the relationship between swimming ability, fish morphology and home range. Long distance movement data were obtained in a mark-recapture experiment held in the field between June and September - 2008, on five sites along the Ubatiba stream. For this study, we had one day to mark fishes, on June-19, and 14 events for recapture. Considering the ten species that inhabit the study area, our study showed that four species: Astyanax janeiroensis, Astyanax hastatus, Parotocinclus maculicauda and Pimelodella lateristriga, moved at least 6 000m in 60 days. The other six species did not present long distance movements, as they were recaptured in the same site 90 days after being marked. For short distance study, movement data were obtained in one mark-recapture experiment held in a 100m long site subdivided into five 20m stretches where fishes were marked with different elastomer colours. We marked 583 specimens that after recapture showed two groups of different movement patterns. The first group was called “Long Movement Group” and the second one was called “Short Movement Group”. The Long Movement Group showed, on average, 89.8% of moving fishes and 10.2% of non moving fishes, against 21.3% and 78.7%, respectively, for the Short Movement Group. It was concluded that fish movement could explain the previously mentioned community stability, and that it is correlated to specific morphological attributes.A pesar de su importancia en la investigación ecológica, no se conocen estudios sobre patrones de movimiento y del ámbito de hogar de peces que habitan pequeños ríos de los bosques tropicales brasileños. El objetivo del presente estudio fue describir los patrones de movimiento de larga y corta distancia de peces de un arroyo de la Mata Atlântica (22°60” S - 42°48” W). Los datos de los movimientos de larga distancia se obtuvieron mediante un experimento de marcación-recaptura realizado en cinco sitios distribuidos a lo largo de 10km del río Ubatiba. Considerando las diez especies que habitan el área de estudio, observamos que cuatro se movieron por lo menos 6 000m en 60 días. Las otras seis especies no presentaron movimientos de larga distancia. Para los estudios de corta distancia se obtuvieron datos de marcación-recaptura en un sitio de muestreo con 100m de longitud subdividido en cinco tramos de río con 20m. Los especímenes recapturados presentaron dos grupos con patrones distintos de movimiento; un grupo con mayor movimiento y otro grupo de poco movimiento. Concluímos que el movimiento de los peces podría explicar la estabilidad de la comunidad previamente mencionada, y que está correlacionado a los atributos morfológicos específicos.

Length–length and length–weight relationships was estimated for 48 fish species collected in 30 neotropical reservoirs located in the State of Parana ´, Brazil. Significant relations were found for all species. The values of the parameter slope (b) in the length–weight relationship ranged from 2.49 to 3.46 for grouped sexes, and from 2.66 to 3.15 for separated sexes. Differences between sexes (indication of sexual dimorphism) were verified for 20 species. Males exhibited greater lengths than females for Astyanax janeiroensis, Bryconamericus iheringii, Geophagus brasiliensis, Glanidium ribeiroi and Hypostomus derbyi, whereas females attained greater lengths than males for the other 15 species examined in this study.

Aspects of the reproductive biology of Astyanax janeiroensis in the Ubatiba river in Maricá, RJ, Brazil were evaluated in order to ascertain whether the strategy adopted by the species is causally related to environmental variables. Specimens were collected on a monthly basis from October 1994 to September 1995, through electrofishing. The Sex ratio was not significantly different from the expected frequency of 1:1 (G = 1.29; p > 0.50); nonetheless, considering three standard length classes, significantly larger numbers of females were recorded for the higher SL class (G = 11.07; p < 0.01). Size at first maturation showed no significant differences between sexes. Length-weight ratio analyses showed negative allometry for males and isometry, for females. Length structure was significantly different between sexes, suggesting that females are larger than males (D = 0.027, p < 0.01). Reproductive specimens were recorded during nine months of the annual cycle. Seasonal variations of reproductive specimens belonging to two different standard length classes displayed an asynchronous behavior, with larger specimens having a longer reproductive period and smaller ones reproducing for fewer months during the annual cycle. High values of fecundity (F), varying from 3169 to 18714 oocytes, were recorded for fish of 9.1 and 10.2 cm lengths, respectively. The correlation between weight and number of oocytes/unit of weight was positive, indicating that larger specimens produced more eggs.

– In this study, we explored patterns of size and abundance of Astyanax janeiroensis in Rio Ubatiba (Rio de Janeiro, south-east Brazil) in relation to reproduction. A. janeiroensis broadcast their eggs in the water column throughout the year. Samples at seven sites conducted every second month from July 1994 to August 1995 revealed a predominance of larger adult specimens upstream and immature juveniles downstream. We hypothesize that upstream movements of adult individuals is a response to drifting of eggs and larvae.

Astyanax janeiroensis: rio Ribeira de Iguape basin:MHNCI 5921, 28 (2 c&s), ribeir��o Pocinha, 8 Nov 1988; MZUSP 60163, 6, c��rrego do Franco, 24��47���S48��33���W, 22 Mar 2000; MZUSP 71873, 2, rio Ca��ador, approx. 24��35���S49��19���W, 6 Jan 2000; MZUSP 79510, 5, stream tributary of rio Tr��s Barras, approx. 25��18���S49��34���W, 16 May 2002., Published as part of Vin��cius Abilhoa & Luiz Fernando Duboc, 2007, A new species of the freshwater fish genus Astyanax (Ostariophysi: Characidae) from the rio Iguacu basin, southeastern Brazil., pp. 43-52 in Zootaxa 1587 on page 51