A pesca e o conhecimento ecológico local dos pescadores de acará-disco (Symphysodon aequifasciatus, Pellegrin 1904: Cichlidae) na Reserva de Desenvolvimento Sustentável Piagaçu-Purus, baixo rio Purus, Brasil

The discus fish (Symphysodon aequifasciatus, Pellegrin 1904), an endemic cichlid from the Amazon basin, is one of the most popular ornamental fish species in the world. However, there is little information available in the scientific literature on the exploitation of this species in its natural habitat. In this article we describe the small-scale discus fisheries activity in the Reserva de Desenvolvimento Sustentável Piagaçu-Purus (RDS-PP), lower Purus River, Brazil, based on field observations, structured and open-ended interviews with fishermen and local inhabitants. Discus fishery is seasonal, occurring mainly in the dry season. Local fishermen use fish attractors to catch the species and underwater hearing methods to estimate its presence and abundance. Discus fishes are locally kept in wooden storage tanks and carried in plastic containers for distribution in regional markets by means of fishing boats, commercial boat lines or rafts. Discuses are sold in Manaus, State of Amazonas, to export companies specialized in ornamental fish trade. We describe the local ecological knowledge on the discus among fishermen living within the RDS-PP and discuss its importance for ornamental fishery management in that protected area

Patterns of energy allocation to reproduction in three Amazonian fish species

The study considered the influence of the hydrological cycle and gonadal development on the accumulation and use of energy in three fish species from an Amazonian flooded area. Fishes were sampled over a 24 hour period at monthly intervals between July 2004 and June 2005 using gillnets of different mesh sizes. Body cavity fat and gonadosomatic indices were determined, as well as energy content of gonads and muscles. Amongst the studied species, different means of energy allocation for reproduction were found: Acestrorhynchus falcirostris allocate energy from body cavity fat to its gonads; Pygocentrus nattereri uses mainly energy accumulated in the muscles for the process of gonadal maturation; and Hoplosternum littorale uses energy accumulated in their muscles and body cavity fat for reproductive processes. It is quite clear that the flood pulse regulates the gain and use of the energy reserves in fishes from the Amazonian floodplain. © 2010 Sociedade Brasileira de Ictiologia

Phylogenetic community structure: Temporal variation in fish assemblage

Hypotheses about phylogenetic relationships among species allow inferences about the mechanisms that affect species coexistence. Nevertheless, most studies assume that phylogenetic patterns identified are stable over time. We used data on monthly samples of fish from a single lake over 10 years to show that the structure in phylogenetic assemblages varies over time and conclusions depend heavily on the time scale investigated. The data set was organized in guild structures and temporal scales (grouped at three temporal scales). Phylogenetic distance was measured as the mean pairwise distances (MPD) and as mean nearest-neighbor distance (MNTD). Both distances were based on counts of nodes. We compared the observed values of MPD and MNTD with values that were generated randomly using null model independent swap. A serial runs test was used to assess the temporal independence of indices over time. The phylogenetic pattern in the whole assemblage and the functional groups varied widely over time. Conclusions about phylogenetic clustering or dispersion depended on the temporal scales. Conclusions about the frequency with which biotic processes and environmental filters affect the local assembly do not depend only on taxonomic grouping and spatial scales. While these analyzes allow the assertion that all proposed patterns apply to the fish assemblages in the floodplain, the assessment of the relative importance of these processes, and how they vary depending on the temporal scale and functional group studied, cannot be determined with the effort commonly used. It appears that, at least in the system that we studied, the assemblages are forming and breaking continuously, resulting in various phylogeny-related structures that makes summarizing difficult. © 2014 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd

A new species of Dadayius Fukui, 1929 (Digenea: Cladorchiidae), parasite of Symphysodon aequifasciatus Pellegrin, 1904 (Perciformes: Cichlidae) from the Purus River, Amazon, Brazil

Summary: The present paper describes a new species of Dadayius Fukui, 1929 (Trematoda, Digenea), parasite of Symphysodon aequifasciatus Pellegrin, 1904, a freshwater fish. The fish were collected from the Purus River, Amazonas State, Brazil. This new species has a long body and, different from other species of the genus, an arch-shaped ovary and a sinuous oesophagus with an ovoid bulb. This is the first record of Dadayius in cichlid fish; to date Dadayius has only been found parasitizing characid fish. © 2011 © Versita Warsaw and Springer-Verlag Wien

A database of freshwater fish species of the Amazon Basin

The Amazon Basin is an unquestionable biodiversity hotspot, containing the highest freshwater biodiversity on earth and facing off a recent increase in anthropogenic threats. The current knowledge on the spatial distribution of the freshwater fish species is greatly deficient in this basin, preventing a comprehensive understanding of this hyper-diverse ecosystem as a whole. Filling this gap was the priority of a transnational collaborative project, i.e. the AmazonFish project - https://www.amazon-fish.com/. Relying on the outputs of this project, we provide the most complete fish species distribution records covering the whole Amazon drainage. The database, including 2,406 validated freshwater native fish species, 232,936 georeferenced records, results from an extensive survey of species distribution including 590 different sources (e.g. published articles, grey literature, online biodiversity databases and scientific collections from museums and universities worldwide) and field expeditions conducted during the project. This database, delivered at both georeferenced localities (21,500 localities) and sub-drainages grains (144 units), represents a highly valuable source of information for further studies on freshwater fish biodiversity, biogeography and conservation

A review of the South American cichlid genus Cichla, with descriptions of nine new species (Teleostei: Cichlidae)

Cichla, with the junior synonym Acharnes, is widely distributed in the Amazon, Tocantins, and Orinoco river basins, and in the smaller rivers draining the Guianas to the Atlantic Ocean. Within South America transplantations are recorded from the Paraná and Paraguay river drainages in Paraguay and Brazil, and the Paraíba do Sul and Paraguaçu rivers in Brazil. The genus comprises 15 species recognized by external characters of which colour pattern and meristics are most significant. In six species juveniles possess three dark blotches on the side and a dark band connecting the posterior blotch to the dark blotch at the caudal-fin base: Cichla ocellaris is known from the Guianas, including the Marowijne, Suriname, Corantijn, Demerara, and Essequibo river drainages, and also the upper Rio Branco in Brazil. Cichla orinocensis is known from the Negro and Orinoco river drainages in Brazil, Colombia, and Venezuela. Cichla monoculus is widespread in the floodplains of the Amazon basin, in Colombia, Peru, and Brazil, and also collected from rivers of Amapá in Brazil, and the lower Oyapock River on the border between Brazil and French Guiana. Cichla nigromaculata is known from the upper Rio Orinoco in Venezuela and, tentatively, the middle Rio Negro in Brazil. Cichla kelberi, new species, is restricted to the Tocantins river basin, but also found transplanted in the Paraná and Paraíba do Sul river drainages and reported from the Nordeste region of Brazil. Cichla pleiozona, new species, occurs in the Madre de Dios, Beni, and Guaporé river drainages in Bolivia and Brazil, and in the Rio Jamari in Brazil. A lectotype is fixed for Cychla toucounarai which is a synonym of Cichla monoculus. Juveniles and young of the remaining nine species, in addition to the three midlateral blotches, possess a dark horizontal band extending from the head to the dark blotch at the caudal-fin base: Cichla mirianae, new species, is restricted to the upper Tapajós river drainage, in the Juruena and Teles Pires rivers, and the upper Xingu river drainage in Brazil. Cichla melanine, new species, is restricted to the lower Xingu river drainage in Brazil. Cichla piquiti, new species, is restricted to the Tocantins river basin, but transplanted in the Paraná river basin in Brazil and Paraguay. Cichla thyrorus, new species, occurs in the Rio Trombetas in Brazil, upstream from the Cachoeira Porteira. Cichla jariina, new species, occurs in the Rio Jari in Brazil, where it is so far recorded only from the region of the Santo Antonio rapids. Cichla pinima, new species, occurs in the lower parts of southern tributaries of the Rio Amazonas in Brazil (Tapajós, Curuá-Una, Xingu), and the lower Tocantins and Capim rivers. Tentatively identified specimens are recorded from the Amapá, Araguari, and Canumã rivers in Brazil. Cichla pinima occurs translocated in the Rio Paraguaçu in southeastern Brazil, and is reported as translocated from the northeast of Brazil. Cichla vazzoleri, new species, occurs in the Uatumã and lower Trombetas rivers in Brazil. Cichla temensis is known from the Negro and Orinoco river drainages in Brazil, Colombia, and Venezuela. It is also recorded from blackwater rivers along the Rio Solimões-Amazonas in Brazil (Tefé, Rio Puraquequara, Rio Uatumã, and Silves). Cichla intermedia is restricted to the Casiquiare and Orinoco river drainages in Venezuela. A phylogenetic analysis suggests that C. intermedia, C. piquiti, and C. melanine are successive basal species, whereas an unresolved group composed of C. jariina, C. pinima, C. temensis, C. thyrorus, and C. vazzoleri is the sister group of (C. mirianae,(C. orinocensis,((C. ocellaris, C. nigromaculata),(C. monoculus, C. kelberi, C. pleiozona))). © 2006 by Verlag Dr. Friedrich Pfeil

Diving in the sand: The natural history of Pygidianops amphioxus (Siluriformes: Trichomycteridae), a miniature catfish of Central Amazonian streams in Brazil

The natural history of Pygidianops amphioxus de Pinna and Kirovskyi (Neotropical Ichthyology 9:493-504, 2011), a highly specialized sand-dwelling catfish species, was studied based on underwater observations in a small forest stream in the central Amazon. Information on the feeding and reproductive biology was obtained by means of analyses of preserved specimens. These miniature catfishes remained buried in the sand at the bottom of the stream and were never observed swimming in open water. The catfish consumed small benthic invertebrates, particularly Chironomidae larvae and Harpacticoida copepods, which were most likely captured by suction feeding inside the sand banks. Pygidianops amphioxus displays sexual dimorphism in the shape of the urogenital papilla and in the body length, with adult females being relatively longer than males. Sexually mature females were found throughout the year and carried a small number of proportionally very large oocytes. A short duration (24 h) experiment conducted in aquaria revealed that these small catfishes exhibit the predominantly nocturnal habits typical of most Siluriformes. © 2013 Springer Science+Business Media Dordrecht

Seasonal changes in the use of feeding resources by fish in stands of aquatic macrophytes in an Amazonian floodplain, Brazil

This study aimed to characterize the food intake by the fish assemblage inhabiting aquatic macrophytes stands, evaluating the changes in food availability among the periods of the hydrologic cycle and the trophic responses of the fish assemblage along with food availability. Fish sampling was conducted in stands of aquatic macrophytes (predominantly Paspalum repens, Poaceae) along banks of the Trombetas River during the four hydrologic periods (rising, high, receding, and low water level) that represent different phenological conditions of the habitat. The food consumption by the fish assemblage was analyzed for 41 species with stomach contents. The assemblage fed mainly on aquatic insects, periphytic algae and detritus. Food availability analysis showed that food resources changed among periods. Fifteen species were present in more than one period and most of those species showed dietary changes along with the hydrologic cycle, feeding mainly on invertebrates in the rising water period and periphytic algae and detritus in receding and low water periods. Only four species showed sufficient numbers to be analyzed in relation to diet and food availability along the at least three hydrologic periods, two of which showed a positive correlation between diet and food availability for three of the four periods; the other two species did not show this correlation, and presented omnivorous habits. In all cases, the selectivity values for the most important food items were near zero, indicating that intake was not motivated by feeding preference. Our results suggest that both trophic plasticity and omnivorous diets are important adaptations for species that inhabit temporally variable habitats such as aquatic macrophytes stands. © 2013 Springer Science+Business Media Dordrecht

Discus fishes: Mitochondrial DNA evidence for a phylogeographic barrier in the Amazonian genus Symphysodon (Teleostei: Cichlidae)

Genetic relationships and variation in meristic counts, body shape and colour were examined in a large sample of Symphysodon collected from several locations in floodplain habitats along the length of the Amazon River. Surprisingly, mitochondrial DNA indicates no difference between the two historically described species, Symphysodon discus and Symphysodon aequifasciatus, but shows that non-clinal variation exists with a distinct lineage found in the western Amazon. This lineage is consistent with a colour form that is distinct from other Symphysodon lineages. This form has a parapatric distribution and is recognized as a distinct species, Symphysodon tarzoo. Adaptation to floodwater habitats supports genetic cohesion across a large range preventing fine scale regional diversification of the genus. Possible explanations for the unusual set of distributions for genetic and colour characters relate to the history of the Amazon basin and the probable division of lowland species when submerged geologic arches influence surface topology. © 2006 The Fisheries Society of the British Isles

Structure and dynamics of stream fish communities in the flood zone of the lower Purus River, Amazonas State, Brazil

The structure and dynamics of fish communities were characterized by richness, abundance, diversity and stability, during high-water and low-water periods. These analyses were performed on data from the flood zone of four streams in the lower Purus River, in the Brazilian Amazon. A total of 188 species of fish were collected, distributed among 29 families and eight orders. The statistical test showed a difference in community diversity between periods. The high-water period showed higher evenness in comparison to the low-water season. The low-water period was marked by high species abundance. A great variation in community composition between the flood and low-water periods was encountered. The adjustments for species abundance models suggested that stochastic events structure the communities. Most of the species showed a temporal variation of abundance indicating low community stability. Changes in the physico-chemical conditions of the water caused by the seasonal hydrological regime may be influencing the structuring of the fish communities. © 2010 Springer Science+Business Media B.V