Ichthyofauna from tributaries of Urubu and Amazonas rivers, Amazonas State, Brazil / Ictiofauna de afluentes dos rios Urubu e Amazonas, Estado do Amazonas, Brasil

Abstract: The Amazonas River basin comprises the world's highest fish species diversity. Anthropogenic interferences in aquatic environments represent a pressure over the maintenance of ecological stability and biodiversity. We inventoried the ichthyofauna of 13 disturbed/modified tributaries of Urubu and Amazonas rivers in the region of the middle Amazon River, between June 2018 and March 2019. A total of 164 species were captured, represented by 11 orders, 37 families and 96 genera. Characiformes was the richest order, followed by Cichliformes and Siluriformes. The most representative families in number of species were Cichlidae, Serrasalmidae, and Characidae. Hemigrammus levis was the most abundant species, and Acarichthys heckelii the most common, registered in all sampled sites. In the present study, species with economic interest were collected, as well as many species recently described and one still waiting for formal description, identified provisionally as Moenkhausia aff. colletii. Therefore, the high fish diversity registered, even in disturbed environments in Middle Amazonas River, denotes the makeable ecological importance of this region for fishes resources and supports the necessity of evaluation of other aquatic environments in the region, as well as the potential impacts on composition, maintenance, and survival of ichthyofauna in environments directly affected by human activities.

Resumo: A bacia do rio Amazonas compreende a maior diversidade de espécies de peixes do mundo. Interferências antropogênicas em ambientes aquáticos representam uma pressão sobre a manutenção da estabilidade ecológica e da biodiversidade. Inventariamos a ictiofauna de 13 afluentes perturbados/modificados dos rios Urubu e Amazonas na região do médio do rio Amazonas, entre junho de 2018 e março de 2019. Foram capturadas 164 espécies no total, representadas por 11 ordens, 37 famílias e 96 gêneros. Characiformes foi a ordem mais rica, seguida por Cichliformes e Siluriformes. As famílias mais representativas em número de espécies foram Cichlidae, Serrasalmidae e Characidae. Hemigrammus levis foi a espécie mais abundante e Acarichthys heckelii a mais comum, registrada em todos os locais amostrados. No presente estudo foram coletadas espécies de interesse econômico, bem como muitas espécies recentemente descritas e uma ainda aguardando descrição formal, identificada provisoriamente como Moenkhausia aff. colletii. Portanto, a alta diversidade de peixes registrada, mesmo em ambientes perturbados no médio rio Amazonas, denota a importância ecológica marcante dessa região para os recursos pesqueiros e suporta a necessidade de avaliação de outros ambientes aquáticos da região, bem como os possíveis impactos na composição, manutenção e sobrevivência da ictiofauna em ambientes diretamente afetados pelas atividades humanas.

Physico-chemical properties and ichthyofauna diversity in Karala River, A Tributary of Teesta River at Jalpaiguri District of West Bengal, India.

The present investigation was carried out on the Karalla River, a tributary of the river Teesta from February, 2009 to July, 2010 at three stations to study the seasonal change of physico-chemical factors and ichthyofaunal diversity. The constituents monitored included air and water temperature, turbidity, pH, total dissolved solid, total suspended solid, total solid, depth, conductivity, dissolved oxygen, biological oxygen demand, free carbon dioxide, chloride, salinity, total alkalinity, hardness, nitrate, phosphate and silicate. Through out the study period the water was hard and a significant variation of the rest parameters was observed. In respect of Ichthyofauna diversity, a total of fifty five species belonging to eight orders and twenty families were identified. Among the 55 species, thirty one species were found under the order Cypriniformes, ten species were found under the order Perciformes, seven species were found under the order Siluriformes, three species were found under the order Synbranchiformes and a single species was found under the order Osteoglossiformes, Anguilliformes, Beloniformes and Tetraodontiformes each. This observation indicates that Cypriniformes order is the most dominating of all other seven important orders. There are thirty three species which were common to all the three sampling stations and hence can be considered as migratory ichthyofauna. In this lotic system the diversity and distribution of fishes were uneven. The un-even distribution and diversity may be due to physico-chemical factors of water, substratum soil quality, and unscientific fish capture technology. The increase in species richness at down streams (SII and SIII) also may be due to the occurrence of submerged weeds.

Ichthyofauna from the Emas National Park region: composition and structure

The relationship between habitats and the ichthyofauna composition in the Parque Nacional das Emas (PNE) and adjacent areas (the Araguaia and Sucuriú rivers) are provided and could be applied in determining the Park's future zoning. Samples of the ichthyofauna and limnological parameters were obtained during both dry (September 1999) and wet (December 1999) seasons. Ichthyofauna collections resulted in the capture of 4,740 specimens of 22 species. The most abundant species in the Araguaia River during the two sampling seasons were Astyanax sp. 2 and Hasemania sp. In the Sucuriú River and PNE, Astyanax scabripinnis cf. paranae and Hoplias aff. malabaricus were the most frequent species. The largest number of species and diversity index were recorded for the Araguaia River. However, sound management policies require more detailed studies on the fish communities of the Cerrado biome.

Com o objetivo de obter informações básicas para o futuro zoneamento do Parque Nacional das Emas (PNE), foram realizadas amostragens ictiofaunísticas e de parâmetros limnólógicos durante o período de seca (setembro/1999) e de chuvas (dezembro/1999) em estações de coletas localizadas no interior do Parque e em áreas adjacentes (rios Araguaia e Sucuriú). Foram capturados 4.740 indivíduos, distribuídos em 22 espécies. Entre as espécies mais abundantes destacam-se Astyanax sp. 2 e Hasemania sp. no rio Araguaia e Astyanax scabripinnis cf. paranae e Hoplias aff. malabaricus no rio Sucuriú e PNE. A maior diversidade de espécies foi constatada para o rio Araguaia. Entretanto, para que medidas de manejo possam ser tomadas de forma criteriosa, estudos ecológicos mais detalhados das comunidades de peixes do cerrado devem ser conduzidos.