ASSEMBLEIA DE PEIXES EM LAGOS DO RIO QUIUINI, UM TRIBUTÁRIO DO RIO NEGRO, AMAZONAS, BRASIL

The objective of this study was to evaluate and characterize the composition and structure of fish assemblages in the black water lakes in the middle Black river, to generate information that can assess the relevance of its fish fauna, both on the local and regional context. Samples were collected in four black waters lakes of the Quiuini river, municipality of Barcelos (AM), during the period of flood and dry, in 2012. The composition of fish assembly was investigated by abundance and biomass. The diversity was determined by the Shannon-Wiener indices, dominance Berger-Parker and Equitability. A total of 1,985 individuals, belonging to 82 species, six orders and 22 families were collected. Characiformes and Siluriformes were dominant groups, represented more than 90% of the total number of collected individuals. The absolute richness-indice (p= <0,05), evenness (p= <0,05) and abundance (p= <0,05) they presented significant differences, while Shannon-Wiener (p= >0,05) and Berger-Parker (p= >0,05) indice’s not differ in the periods studied. The Maranhão lake had the largest richness captured (N=605). However, largest values of Shannon diversity were recorded for the Erudá and Cajutuba lakes. The landscape formed by the Quiuini river permit the diversity and abundance of species. As we can see in this study the richness and diversity of the fish fauna in lakes the Quiuini river still needs to be further explored in the other phases of the hydrological cycle (flooding and drying) to better understand distribution processes and patterns of fish assemblages in black water lakes.Keywords: Amazon basin; ichthyofauna; flood; dry; diversity.O objetivo desse trabalho foi avaliar e caracterizar a composição e a estrutura das assembleias de peixes nos lagos de água preta do médio rio Negro, para gerar informações que podem avaliar a relevância de sua ictiofauna, tanto no contexto local e regional. As coletas foram realizadas em quatro lagos de águas pretas do rio Quiuini, município de Barcelos (AM), durante o período sazonal de cheia e seca, no ano de 2012. A composição da assembleia de peixes foi investigada através da abundância e biomassa. A diversidade foi determinada através dos índices de Shannon-Wiener, dominância de Berger-Parker e Equitabilidade. Foram coletados 1.985 exemplares de peixes distribuídos em seis ordens, 22 famílias e 82 espécies. Characiformes e Siluriformes foram os grupos dominantes, representando mais de 90% dos indivíduos capturados. Os índices de riqueza absoluta (p= <0,05), equitabilidade (p= <0,05) e abundância (p= <0,05) apresentaram diferenças significativas, enquanto Shannon-Wiener (p=>0,05) e Berger-Parker (p=>0,05) não apresentaram diferenças nos períodos estudados. O lago que teve o maior número de espécies capturadas (N=605) foi o Maranhão. Contudo, os valores mais elevados de diversidade de Shannon, foram registrados para os lagos Erudá e Cajutuba. A paisagem constituída pelo rio Quiuini possibilita a diversidade e a abundância das espécies. A partir desse estudo, consideramos que a riqueza e a diversidade da ictiofauna nos lagos do rio Quiuini ainda necessita ser mais explorada nas outras fases do ciclo hidrológico (enchente e vazante) para entender processos e padrões de distribuição das assembleias de peixes de lagos de águas pretas.Palavras-Chave: bacia amazônica, ictiofauna, cheia, seca, diversidade

Fish, upper Purus River, state of Acre, Brazil

The ichthyofauna of the headwaters of the main tributaries of the mighty Solimões/Amazonas River hasbeen little studied. Considering the importance of those environments for the overall fish diversity in that river system,we surveyed the composition of the fish fauna of the upper portion of Purus River and two of its tributaries (Caeté andMacapá rivers), state of Acre, Brazil. The collections were done in November 2004, using a seine net and a set ofgillnets of different mesh sizes. A total of 735 specimens belonging to 86 species and 28 families were collected. Eightspecies, Creagrutus occidaneus, Phenacogaster pectinatus, Prionobrama filigera, Moenkhausia cf. lepidura,Leptagoniates pi (Characidade), Henonemus punctatus (Trichomycteridae), Toracocharax stellatus (Gateropelecidae),and Eigenmannia macrops (Sternopygidae) composed nearly half of the specimens collected. This survey adds 48 newrecords to the ichthyofauna of Purus River and elevates to 243 the number of known fish species in that river, but agreater sampling effort is necessary to produce a reasonably complete picture of the fish diversity in the basin

Parasitism of Arapaima gigas (Schinz, 1822) in fish farms of the state of Amazonas, Brazil

Abstract The objective of this study was to investigate the parasites occurrences and to determine the rates of infestation/parasitic infection in juvenile Arapaima gigas from seven fish farms in the state of Amazonas, relating to the characteristics of these fish farms. Of the 70 A. gigas evaluated, 43 were infested/infected, with a total of 133 parasites collected. Three fish farms (2, 4, 6) showed the highest levels of prevalence of parasites (100%, 70%, 70%), mean intensity (4.1±2.6, 8.1±9.2, and 2.1±1.3), and mean abundance (4.1±2.6, 5.7±8.1, and 1.5±1.5), respectively. Prevalence ranged from 30% to 100%, mean intensity from 1.0 to 8.1 and mean abundance from 0.3 to 5.7. Monogenea, Digenea, Nematoda (Hysterothylacium sp. and Spirocamallanus sp.) and Acanthocephala (Neoechinorhynchus sp. and Polyacanthorhynchus sp.) were identified. The parasites Hysterothylacium sp. and Neoechinorhynchus sp. were the most prevalent parasites with 31.43% and 15.71%, respectively. The fish presented negative allometry in growth and constant condition factor. Measures to prevent and control the parasitic diseases diagnosed are discussed as well prophylactic practices that contribute to the biosecurity of the farms

The Silent Threat of Non-native Fish in the Amazon: ANNF Database and Review

Non-native fish (NNF) can threaten megadiverse aquatic ecosystems throughout the planet, but limited information is available for the Amazon Region. In this study we review NNF data in the Amazonian macroregion using spatiotemporal records on the occurrence and the richness of NNF from a collaborative network of 35 regional experts, establishing the Amazon NNF database (ANNF). The NNF species richness was analyzed by river basin and by country, as well as the policies for each geopolitical division for the Amazon. The analysis included six countries (Brazil, Peru, Bolivia, Ecuador, Venezuela, and Colombia), together comprising more than 80% of the Amazon Region. A total of 1314 NNF occurrence records were gathered. The first record of NNF in this region was in 1939 and there has been a marked increase in the last 20 years (2000–2020), during which 75% of the records were observed. The highest number of localities with NNF occurrence records was observed for Colombia, followed by Brazil and Bolivia. The NNF records include 9 orders, 17 families and 41 species. Most of the NNF species are also used in aquaculture (12 species) and in the aquarium trade (12 species). The most frequent NNF detected were Arapaima gigas, Poecilia reticulata and Oreochromis niloticus. The current data highlight that there are few documented cases on NNF in the Amazon, their negative impacts and management strategies adopted. The occurrence of NNF in the Amazon Region represents a threat to native biodiversity that has been increasing “silently” due to the difficulties of large-scale sampling and low number of NNF species reported when compared to other South American regions. The adoption of effective management measures by decision-makers is urgently needed and their enforcement needed to change this alarming trend and help protect the Amazon’s native fish diversity.