Fish , Marmelos Conservation Area ( BX 044 ) , Madeira River basin , states of Amazonas and Rondônia , Brazil

The present study provides a species list of fish from the Marmelos River Area – BX044 in the states of Amazonas and Rondônia in northern Brazil. During a Rapid Ecological Assessment (REA) performed in October and November of 2003, 133 fish species from six orders and 24 families were recorded. The most diverse families were Characidae (47 species), Cichlidae (15 species), Loricariidae (12 species) and Pimelodidae (7 species). 23 fish species were common to the entire river basin and 4 were endemic to the aquatic system studied. Introduction In the most recent Brazilian Workshop held in Macapá City in 1999 to define priorities for the conservation and sustainable use of the Amazon, the Marmelos Area (BX044) was indicated as an A level priority for the assessment of fish fauna and other vertebrates. The Marmelos BX044 area is a unique ecosystem in the Brazilian Amazon, encompassing different forest formations, such as patches of grassland, Ombrophylus closed forest, open forest and savannas. These features, together with the potential endemism and proven fish richness, have led scientific authorities to consider this area as one of 385 priority areas for biodiversity conservation (Capobianco et al. 2001). The BX044 area is included in the deforestation arc of the Brazilian Amazon. Its natural landscapes are in accelerated anthropogenic transformation and there is limited knowledge on fish fauna diversity (Capobianco et al. 2001). This indicates the urgent need to study the regional fish fauna in order to draft appropriate conservation plans and define new conservation units. This paper contains the first documentation of the fish fauna of the Marmelos BX044 area in the Amazon. It is based on a field survey conducted during the PROBIO Rapid Ecological Assessment (REA) project. REA is a methodology used to survey diversity and current geographic distribution as well as elucidate the biogeography patterns of occurrence of the different taxa (Camargo et al. 2005). This approach also contributes toward determining priorities for regional conservation. Knowledge on fish fauna diversity is important in defining potential land use. The ecological importance and geographic location determine the role of this area as an ecological corridor between the areas of the indigenous Tenharin. Materials and methods The BX044 area has 5,270 km and is located between 08°02'52" and 08°54'46" S, and 60°50'24" and 62°10'13"W in the Madeira-Tapajós interfluve. This interfluve is characterized by restricted conservation areas, with no more than six per cent of the total area located in conserved units of direct and indirect use (Figure 1). A field survey was carried out during October and November of 2003 at 23 sites located along the main courses, such as the Maderinha, Roosevelt, and Jatuarana Rivers and streams that drain different forest formations. Sampling was conducted in open savanna habitat (3 sites), dense savanna habitat (5 sites), gallery forest habitat (6 sites), flooding forest habitat (1 site) and Ombrophylus forest habitat (8 sites). Fish were caught using three gill nets (20 m length, mesh size 30, 50 and 70 mm), 2 throw nets (1.5 m length, mesh size 8 mm) and 3 dip nets (mesh size Check List 3(4): 291–296, 2007. ISSN: 1809-127X


Introduction
In the most recent Brazilian Workshop held in Macapá City in 1999 to define priorities for the conservation and sustainable use of the Amazon, the Marmelos Area (BX044) was indicated as an A level priority for the assessment of fish fauna and other vertebrates.The Marmelos BX044 area is a unique ecosystem in the Brazilian Amazon, encompassing different forest formations, such as patches of grassland, Ombrophylus closed forest, open forest and savannas.These features, together with the potential endemism and proven fish richness, have led scientific authorities to consider this area as one of 385 priority areas for biodiversity conservation (Capobianco et al. 2001).
The BX044 area is included in the deforestation arc of the Brazilian Amazon.Its natural landscapes are in accelerated anthropogenic transformation and there is limited knowledge on fish fauna diversity (Capobianco et al. 2001).This indicates the urgent need to study the regional fish fauna in order to draft appropriate conservation plans and define new conservation units.This paper contains the first documentation of the fish fauna of the Marmelos BX044 area in the Amazon.It is based on a field survey conducted during the PROBIO Rapid Ecological Assessment (REA) project.REA is a methodology used to survey diversity and current geographic distribution as well as elucidate the biogeography patterns of occurrence of the different taxa (Camargo et al. 2005).This approach also contributes toward determining priorities for regional conservation.
Knowledge on fish fauna diversity is important in defining potential land use.The ecological importance and geographic location determine the role of this area as an ecological corridor between the areas of the indigenous Tenharin.

Materials and methods
The BX044 area has 5,270 km 2 and is located between 08°02'52" and 08°54'46" S, and 60°50'24" and 62°10'13"W in the Madeira-Tapajós interfluve.This interfluve is characterized by restricted conservation areas, with no more than six per cent of the total area located in conserved units of direct and indirect use (Figure 1).
A field survey was carried out during October and November of 2003 at 23 sites located along the main courses, such as the Maderinha, Roosevelt, and Jatuarana Rivers and streams that drain different forest formations.Sampling was conducted in open savanna habitat (3 sites), dense savanna habitat (5 sites), gallery forest habitat (6 sites), flooding forest habitat (1 site) and Ombrophylus forest habitat (8 sites).Fish were caught using three gill nets (20 m length, mesh size 30, 50 and 70 mm), 2 throw nets (1.5 m length, mesh size 8 mm) and 3 dip nets (mesh size 2 mm).Sampling effort was daily with an intensity of three to 12 hours by sampling site, according the stream order.The taxonomy identification was based on keys and descriptions of fish species.Geographic distribution was based in Buckup et al. (2007).

Results and discussion
A total of 133 fish species belonging to six orders and 24 families were recorded (Table 1) in the BX044 area.The most diverse families were Characidae (47 species), Cichlidae (15 species), Loricariidae (12 species) and Pimelodidae (7 species).The current distribution of endemic species indicates the priority of this area for the conservation of fish fauna biodiversity.Such species include Leporinus pachycheilus and Leporinus trimaculatus (Anostomidae) recorded at rapids of the Roosevelt River and Helogenes gouldingi (Cetopsidae) and Synbranchus madeirae recorded on the margins of small streams.Seven potential new undescribed species were recorded for the genus: Brycon "cauda preta"; Bryconops sp.1 and Bryconops sp. 2, Hydrolicus sp. 2 and Gymnotus sp. 1, sp. 2 and sp. 3.No fish species listed as threatened or endangered (sensu IUCN 2006) were recorded in this study.
The diverse taxonomic composition of the trans-Andean ichthyofauna suggests that Miocene tectonism fragmented the entire aquatic fauna of northwestern South America, leaving a clear signal on all major taxa (Albert et al. 2006).This hypothesis was corroborated by the occurrence of some fish species recorded in the Marmelos conservation area and in other remote systems The specimens were identified, preserved in alcohol and deposited in the Ichthyological Collection of the Laboratório de Biologia Pesqueira e Manejo de Recursos Aquáticos of the Universidade Federal do Pará, Brazil.

Table 1 .
Fish species collected in the Marmelos River (BX044) Conservation Area in the states of Amazonas and Rondônia, Brazil from October to November of 2003.