Composition and trophic structure of the ichthyofauna from a stream downriver from Santo Antonio Falls in the Madeira River, Porto Velho, RO

Abstract

Belmont Stream is the main tributary of the Madeira River in the area immediately downriver from the Santo Antonio Fall. Samplings were carried out using gill nets in the mouth of this stream between May 2005 and April 2006 and resulted in a list of 74 species. The analyses included values of composition, constancy of occurrence, species richness, abundance, Catch Per Unit of Effort and trophic structure about the ten most abundant species. Characiformes and Siluriformes were dominant order in the samples and Curimatidae (popularly known as "branquinhas") was the most abundant family, represented by Psectrogaster rutiloides (32.57% of the collected specimens), Potamorhina altamazonica (10.72%), and Potamorhina latior (7.79%). The most of species were considered accessory and accidental and richness suggests high values in the rising and high water. Belmont maybe considered as a moderate richness when compared to those found for others Amazon rivers. Detritivorous fishes composed 60% of the assemblage and the constancy of the most abundant species of this family suggests Belmont as an important area to these migratory fishes. Resumo: O igarapé Belmont localiza-se a cerca de 30 km de Porto Velho e é o principal afluente do rio Madeira na área imediatamente a jusante da cachoeira de Santo Antonio. No período compreendido entre maio de 2005 a abril de 2006, dez coletas realizadas na foz deste igarapé geraram uma lista com 74 espécies coletadas por malhadeiras. As análises incluem características físico-químicas do igarapé estudado, valores de riqueza, composição, constância, estrutura trófica da assembléia de peixes e valores de CPUE. O predomínio das ordens Characiformes e Siluriformes confirma o esperado para a Amazônia. A família Curimatidae foi a mais abundante, representada por Psectrogaster rutiloides (32,57%), Potamorhina altamazonica (10,72%) e Potamorhina latior (7,79%), popularmente conhecidas como branquinhas. A riqueza e constância de algumas espécies sugerem um papel especial da área no que diz respeito à transposição das corredeiras pelas espécies. Conclui-se que a estrutura e a composição da ictiofauna na área estudada do igarapé Belmont é marcada por espécies migradoras detritívoras, possivelmente em função do papel do rio Madeira nas rotas migratórias. Palavras-chave: riqueza, dominância, CPUE, rotas migratórias, Amazônia.

Disturbance calls of five migratory Characiformes species and advertisement choruses in Amazon spawning sites

“…In most river confluences, it is possible audibly to detect the occurrence of P. latior , commonly found in the Madeira River (Cella‐Ribeiro et al ., ). Curimatids are the most abundant fishes (56%) in a 1 km stretch of the black‐water tributary (Belmont River) upstream from its mouth near its connection with the Madeira River (Araújo et al ., ).…”

Composition of the Ichthyofauna of the Igarapé Praquiquara, Castanhal, Eastern Amazon

“…Súarez (1998) comments that the dominance of Characiformes is attributed to the greater capacity of these fish to obtain oxygen from upper layers of the water column. The higher proportion of Characiformes may represent up to 70% of the composition (Araújo et al, 2009;Anjos et al, 2015), however, there are studies, as well as Pinheiro et al (2016) in the Amazon region, which do not present the highest dominance of this order of fish. The low abundance of Siluriformes found in this study was related to their benthic behavior, which made it difficult to capture the specimens with the fishing gear used.…”

Fishes from the Jaru Biological Reserve, Machado River drainage, Madeira River basin, Rondônia State, northern Brazil

“…These investigations identified 122 species from the Jamari River (Santos 1996), 133 from the Marmelos River (Camargo & Giarrizzo 2007), 447 from the Aripuanã and middle Madeira rivers (Py-Daniel et al 2007), 74 from the Belmont Stream (Araújo et al 2009), 160 from the Guariba and Roosevelt Rivers (Pedroza et al 2012), 189 from the Cuniã Lake (Queiroz et al 2013a), and 174 from the middle Madeira River (Torrente-Vilara et al 2011). A more comprehensive inventory identified 820 species along the Madeira River Basin (Queiroz et al 2013b).…”