Ichthyofauna of two streams in the high basin of the Samborombón River, Buenos Aires province, Argentina

Abstract

The ichthyofauna of the Manantiales (35°0234S; 58°1937W) and El Portugués (35°0416S; 58°2609W) streams, both of them pertaining to the high basin of the Samborombón River, in the Province of Buenos Aires, Argentina, was studied. Abundance, specific richness, diversity and temporary distribution were considered throughout an annual cycle. The specific diversity between both streams was compared and the physical and chemical parameters of the environment analizad. In total 8595 specimens were captured, pertaining to 20 species, 11 families and 5 orders. The order Characiformes was the most widely represented with 10 species and a relative abundance of 50%, followed by the order Siluriformes with 6 species and a relative abundance of 30%. The specific richness in the Manantiales was of 20 species, the annual diversity index was 1.42 and the uniformity index was 0.58. The specific richness in El Portugués was of 17 species, the annual diversity index was 1.51 and the uniformity index was 0.64. Differences in the composition of dominant species were observed. The diversity values are similar to that recorded in Pampasia and southern Brazil streams.

Some aspects of biology of Bryconamericus Iheringii (Ostariophysi: Characidae) in two streams in the high basin of the Samborombón river, Argentina

“…iheringii es una especie permanente de ambos arroyos. En Manantiales es la más capturada con un 49,81% de abundancia relativa, mientras que en el arroyo El Portugués sólo representa el 4,70% de la abundancia relativa (Fernández et al, 2008).…”

Global changes in pampean lowland streams (Argentina): implications for biodiversity and functioning

“…According to Ringuelet (1975), the distribution of species there appears to coincide with an ecologic area where mainly the low temperatures and excessively salty character of the water become translated into limiting survival conditions. The most widely represented fish groups are the Characiformes (three families, 10 species) with a predominance of Cheirodon interruptus, Bryconamericus iheringii, and Pseudocorynopoma doriae (Characidae) plus Cyphocharax voga (Curimatidae; Almirón et al, 2000;Di Marzio et al, 2003;Remes Lenicov et al, 2005;Fernández et al, 2008;López et al, 2008). Those taxa are predators predominantly of micro-and mesoinvertebrates (Escalante, 1983), and their abundance is favored by the presence of submerged or floating aquatic vegetation.…”

Fish assemblage composition and structure in a pampean stream with contrasting land uses

“…Por lo tanto, su extrapolación para arroyos pampeanos con una fauna de peces más empobrecida puede no ser conveniente. Los arroyos pampeanos situados al norte de los cordones serranos de Tandilia y Ventania, poseen mayor riqueza específica (Almirón et al, 2000;Di Marzio et al, 2003;Remes Lenicov et al, 2005;Fernández et al, 2008), y en forma inversa para arroyos ubicados al sur (Casciotta et al, 1999).…”