This study presents an extensive review of published and unpublished occurrence records of fish species in the Rio Negro drainage system within the Brazilian territory. The data was gathered from two main sources: 1) litterature compilations of species occurrence records, including original descriptions and revisionary studies; and 2) specimens verification at the INPA fish collection. The results reveal a rich and diversified ichthyofauna, with 1,165 species distributed in 17 orders (+ two incertae sedis), 56 families, and 389 genera. A large portion of the fish fauna (54.3% of the species) is composed of small-sized fishes < 10 cm in standard length. The main groups are Characiformes (454 species; 39.0%), Siluriformes (416; 35.7%), Gymnotiformes (105; 9.0%), and Cichliformes (102; 8.8%). The species composition differs between the main aquatic environments, such as: main channel (159 species), lakes (296), tributary rivers (596), small streams (234), seasonal beaches (186), and rapids (41). Part of the ichthyofauna is shared with adjacent basins, such as the Orinoco, rivers of the Guiana Shield, lower Solimões/Amazonas and upper Amazonas, which contributes to the remarkable ichthyofaunal diversity of the basin. A high rate of species endemism was observed in Characidae (24), Loricariidae (18), Cichlidae (18) and Callichthyidae (18), totalling 156 species (13.4%) endemic to the basin. An estimation of the species richness for the Rio Negro basin, considering 23 published references, resulted in 1,466 and 1,759 species (Jackknife 1 and 2, respectively), which seems reasonable when considering the large number of morphotypes left out of the present list and the low sampling effort in many areas of the basin. The results presented herein provide an additional tool for environmental managers and decision makers for conservation purposes of one of the richest and most well-preserved sub-basins of the Rio Amazonas system.

RESUMOA pesca artesanal apresenta grande importância para as comunidades indígenas Amazônicas, como meio de subsistência e pelas marcas culturais e de tradição dessas comunidades. Neste estudo analisamos a pesca desenvolvida em quatro comunidades indígenas da etnia Mura da Terra Indígena Lago Ayapuá (TI-LA) no baixo rio Purus. Caracterizou-se a pesca quanto à composição e importância das espécies em peso e número de indivíduos, estrutura e tamanho dos indivíduos capturados, e peso total das capturas, entre outubro e dezembro de 2008. As espécies mais comercializadas foram o aruanã (Osteoglossum bicirrhosum), pescada (Plagioscion squamosissimus), as "feras" (dourada, Brachyplatystoma rousseauxii e filhote Brachyplatystoma filamentosum) e o tucunaré Cichla monoculus. Já as espécies mais consumidas foram aruanã, tucunaré, piranha-caju (Pygocentrus nattereri) e acará-açu (Astronotus crassipinni). Espécies como tucunaré e pescada apresentam tamanhos de captura dentro dos padrões permitidos pela legislação. No entanto, o acará-açu, aruanã, tambaqui (Colossoma macropomum), surubim (Pseudoplatystoma punctifer), caparari (Pseudoplatystoma tigrinum), filhote e dourada não apresentam o mesmo padrão legal. A maior parte da produção (87%) foi destinada para a comercialização com barcos atravessadores. Medidas mitigatórias e preventivas são propostas para garantir a permanência dos estoques pesqueiros e consequentemente a sustentabilidade da pesca e a manutenção da população ribeirinha local. Palavras-chave: Baixo rio Purus, Bacia Amazônica, Pesca de subsistência, Populações indígenas. ABSTRACT

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Hemiodus langeanii, new species, is described based on 20 specimens collected in the rio Amana, a tributary of rio Maués-Açú, rio Amazonas drainage, Brazil. The new taxon can be distinguished from its congeners by its high body .5% in remaining species). The new species also exhibits a large lateral dark spot that is equal to, or greater than, the eye diameter (vs. smaller in remaining species except for H. microlepis). The lack of conspicuous lateral stripe or transverse bands and the low lateral line scales count (68-74) distinguish H. langeanii from some similar species in the genus (scale counts: 94-123 in H. argenteus, 124-148 in H. microlepis, 86-99 in H. orthonops and 77-92 in H . parnaguae). Finally, the new species can be differentiated from H. unimaculatus (which overlaps in the number of lateral line scales) by the higher number of scales between the lateral line and the pelvic fin origin (9-10 vs. 4-7, respectively), which are similar sized above and below lateral line (vs. scales larger bellow the lateral line in H. unimaculatus).Hemiodus langeanii, espécie nova, é descrita com base em 20 espécimes coletados no rio Amana, um tributário do rio Maués-Açú na drenagem do rio Amazonas, na Amazônia Brasileira. O táxon novo pode ser diferenciado de seus congêneres devido ao seu corpo muito alto (27,3%, média 32,3% CP, vs. 18,,5% nas demais espécies). A espécie nova apresenta uma grande mancha lateral escura que é igual ou maior do que o diâmetro do olho (vs. menor nas demais espécies, exceto em H. microlepis). A ausência de faixa longitudinal ou bandas transversais conspícuas, associada a um baixo número de escamas na linha lateral (68-74) distinguem H. langeanii de algumas espécies similares do gênero (94-123 em H. argenteus, 124-148 em H. microlepis, 86-99 em H. orthonops e 77-92 em H . parnaguae). Finalmente, a espécie nova pode ser diferenciada de H. unimaculatus (com a qual apresenta sobreposição na contagem de escamas da linha lateral) devido ao maior número de escamas entre a linha lateral e a origem da nadadeira pélvica (9-10 vs. 4-7, respectivamente), e pelo tamanho similar das escamas acima e abaixo da linha lateral (vs. maiores abaixo da linha lateral em H. unimaculatus).

This research analyzed the biometrics and reproductive characteristics of a group of Hypancistrus sp. L-333 (King Tiger Plecos) in order to gather biological information and aid the rearing of the species in captivity, thus supporting its natural conservation. This species has a natural distribution that is restricted to the lower Xingu River, and is currently threatened by the hydroelectric projects in the region. The acquired specimens were measured, weighed and classified according to sex based on morphometric characteristics (evidence of secondary sexual characteristics) that were later confirmed by dissection. A total of 32 individuals, 16 males and 16 females were identified. Although the length-weight ratio did not present significant differences, the results revealed that the species has secondary sexual dimorphism. The odontodes were more developed in the mid-lateral region of the body, post-dorsal region, caudal peduncle and in the first ray (ossified) of the pectoral fin in males. Histological analyses of the gonads confirmed that all of the fish were adult individuals. The diameter of the oocytes ranged from 0.14 to 2.0 mm, presented three distinct modes, and were synchronous in more than two groups, which evidences batch spawning. Fecundity was low, between 35 and 54 oocytes in the largest batch. This information is novel and important for the identification of reproductive groups, and is aimed at breeding in captivity so that these resources can be exploited in a sustainable way, without harming the already threatened natural stocks.

This study estimated the length–weight relationships of 16 fish species occurring close to the shores of sandy beaches along the lower Negro River basin, Brazilian Amazon. The specimens were captured for one day each month, in October to November 2016, early in the morning and early evening, using trawl net (20 m taken for standard length (SL – 0.1 cm precision) and total weight (TW – 0.01 g precision). The parameters a and b of the equation WT = a.LTb were estimated. The a values ranged from 0.0018 to 0.0226 and b values ranged from 2.5271 to 3.3244. This study also provides new data on of maximum lengths for six species, Amazonsprattus scintilla, Brycon pesu, Moenkhausia megalops, Pachyurus paucirastrus, Reganella depressa and Trachydoras microstomus, and new reports of the LWRs parameters of 15 fish species.

The updated status of the ornamental fish trade from the Amazonas state was analyzed between the years of 2006-2015 (IBAMA database). The trade of ornamental fish from Amazonas state mainly consists of species extracted from nature. A total of 142,552,253 specimens were exported during the studied period. Sales plummeted since 2006, from 26,075,241 specimens exported then to 2,729,846 specimens in 2015 (Jan-Jul). Between 2006 and 2015, a total of US$ 23.0 million in revenue was generated from fish exports destined to 35 countries. Germany, Taiwan, USA and Japan accounted for 75.5% of the volume and 76.7% of the value exported. During this time, 375 species were exported, included Paracheirodon axelrodi, P. simulans, Hemigrammus bleheri, Otociclus affinis and O. hoppei that together represented 84.5% of exports. Thirty are not on the list of IBAMA species released for export, and six are currently on the list of endangered fauna of Brazil, being them: Hopliancistrus tricornis, Leporacanthicus joselimai, Parancistrus nudiventris, Peckoltia compta, Scobinancistrus auratus and S. pariolispos. These results are an additional tool for managers, environmentalists and decision makers to establish regulations to govern the trade.

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