Macrobrachium amazonicum is the most frequently consumed freshwater crustacean by river communities of the Amazon. Despite its relative abundance and vast knowledge on the species from data on cultivated specimens, little is known regarding its biology in the natural environment, especially its use of creeks that are strongly influenced by the tide. Specimens of Macrobrachium amazonicum were collected in September 2006 (dry season) and March 2007 (rainy season) from two perennial creeks of the Guajará Bay in the state of Pará (northern Brazil), using traps similar to the matapis used by local fishermen to identify the spatial distribution of the species. Shrimps of all sizes use the tidal creeks in both seasons, including for breeding purposes. The greatest abundance of the species occurred in headwater areas and in the dry season. It is suggested that abundant allochthonous organic matter and the preference for protected areas may explain the abundance and breeding activity of this species in the headwaters of the creeks.Keywords: creek, Macrobrachium, Amazon River prawn, estuary.Distribuição espacial do camarão-da-amazônia -Macrobrachium Amazonicum (Heller, 1862) (Decapoda, Caridea, Palaemonidae) em dois canais perenes de um estuário da costa norte do Brasil (Baía do Guajará -Belém, Pará, Brasil) ResumoMacrobrachium amazonicum é o crustáceo dulcícola mais frequentemente consumido pelas populações ribeirinhas da Amazônia. Entretanto, apesar de sua relativa abundância e vasto conhecimento da espécie a partir de dados de cultivo, pouco se conhece sobre sua biologia no ambiente natural, especialmente quanto à forma de utilização de canais fortemente influenciados pelas marés. Amostras desse camarão foram coletadas em setembro/06 (período seco) e março/07 (período chuvoso), em dois canais perenes da Baía do Guajará, Pará, utilizando armadilhas (matapis) como as utilizadas pelos pescadores locais para identificar a distribuição espacial dos organismos. Os canais de maré são utilizados por camarões de todos os tamanhos nas duas estações do ano, inclusive para a reprodução. A maior abundância de indivíduos da espécie foi encontrada no período seco, nas áreas a montante dos canais . Postula-se que a abundante matéria orgânica alóctone e a busca de locais protegidos podem ser os fatores que explicam a concentração da abundância e da atividade reprodutiva nas áreas a montante dos canais.Palavra-chave: canais de maré, Macrobrachium, camarão-da-amazônia, estuário.

The present study analyzed and compared the daily consumption of foods of animal origin in eleven communities of the Lower Amazon, Trombetas and Purus Rivers, representing three different management systems and levels of conservation in the Brazilian Amazon. All food items of animal origin were weighed by at least 10% of the families in the study communities during a week in each period of the flood cycle between 2006 and 2008. Fish was the most important food, and was consumed during six days of the week, with an average rate of 169 kg.person -1 .year -1 . Game was second in importance, with 37 kg.person -1 . year -1 . This yearly rate of fish consumption is one of the highest in the world and is almost double the minimum recommended by the World Health Organization. The dietary patterns reflect both the isolation of the communities from large urban centers and the better preservation of the local environments due to the existence of protected areas. Environmental degradation may thus have effects on the health and food security of local populations. The study emphasizes the need for the implementation of public policies and participative management initiatives.

1. Human population growth is a major cause of species extinction worldwide, and tropical fresh waters are among the most imperilled ecosystems. The identification of major drivers of human impacts on fish can benefit conservation programmes and management plans.2. The influences of the proximity to urban centres and human population size on six ecological indicators of fish communities (abundance, biomass, richness, diversity, average size, and size dominance pattern) were investigated in 48 floodplain lakes of five main rivers of the Brazilian Amazon (Tocantins, Tapajós, Negro, Solimões, and the Lower Amazon). These ecological indicators were also compared among the rivers studied and checked for any influence of the environmental variables of lakes (size, shape of natural shoreline, distance to the main river channel, depth, transparency, conductivity, and dissolved oxygen).3. Lake distance to urban centre was positively related to average fish size and dominance of large fish, indicating direct human effects caused by fisheries or indirect effects by habitat alteration (e.g. deforestation). Unexpected positive relationships between human population size and the richness and diversity of fishes were found, and may be caused by ecological compensatory effects, the abundance of rare non-fished species, or the proximity of an urban centre to ecotone areas.The other ecological indicators were unrelated to anthropogenic variables. Environmental factors affected fish communities, but did not change the conclusions regarding the effect of the anthropogenic variables. River basin was strongly related to species richness, diversity, biomass, and abundance of fish. Distance to the river channel was positively related to fish biomass. 4. The disappearance of large fish threatens the food security of riverine communities, and may harm essential ecosystem services. Conservation measures, including local management initiatives, protected areas, fisheries monitoring, and the

Artisanal fishing on the northern coast of Brazil is characterized by a set of different fishery modalities. Using a multidisciplinary approach, 20 fishery production systems were identified, with distinct characteristics regarding technology and purpose. The characteristics of each system were classified into five dimensions (ecological, economic, social, technological and political). Multidimensional scaling revealed that some of these 20 systems have greater similarities. Thus, a total of 10 groups were identified.

The present study characterises the commercial fisheries of the basin of the Xingu River, a major tributary of the Amazon River, between the towns of Gurupá (at the mouth of the Amazon) and São Félix do Xingu. Between April, 2012, and March, 2014, a total of 23,939 fishing trips were recorded, yielding a total production of 1,484 tons of fish, harvested by almost three thousand fishers. The analysis of the catches emphasizes the small-scale and artisanal nature of the region's fisheries, with emphasis on the contribution of the motorised canoes powered by "long-tail" outboard motors. Larger motorboats operate only at the mouth of the Xingu and on the Amazon. Peacock bass (Cichla spp.), croakers (Plagioscion spp.), pacu (a group containing numerous serrasalmid species), aracu (various anostomids), and curimatã (Prochilodus nigricans) together contributed more than 60% of the total catch. Mean catch per unit effort was 18 kg/fisher, which varied among fishing methods (type of vessel and fishing equipment used), river sections, and time of the year. In most cases, yields varied little between years (2012 and 2013). The technical database provided by this study constitutes an important resource for the regulation of the region's fisheries, as well as for the evaluation of future changes resulting from the construction of the Belo Monte dam on the Xingu River.Keywords: fish production, fishers, fishing effort, fishery yield. Pescarias artesanais da bacia do Rio Xingu na Amazônia Brasileira ResumoEste trabalho teve como objetivo caracterizar a pesca comercial de consumo na bacia do rio Xingu, afluente do rio Amazonas, no trecho entre a cidade de Gurupá (localizada na foz do Rio Amazonas) até São Félix do Xingu, no estado do Pará, Brasil. No período de abril de 2012 a março de 2014 foram registradas 23.939 viagens de pesca, totalizando uma produção de 1.484 toneladas de pescado, obtidas por quase 3.000 pescadores. A análise dos dados oriundos do monitoramento dos desembarques demonstrou que a pesca na região tem caráter artesanal de pequena escala, destacando-se a participação de canoas motorizadas que utilizam um motor de popa chamado "rabeta". Os barcos motorizados atuam somente na foz do rio Xingu e no rio Amazonas. Tucunaré (Cichla spp), pescada-branca (Plagioscion spp), pacu (várias espécies de Serrasalmidae), aracu (várias espécies de Anostomidae) e curimatã (Prochilodus nigricans) perfazem mais de 60% do total capturado. A captura média por unidade de esforço é de 18 kg.pescador -1 .dia -1 e muda dependendo da modalidade de pesca (tipo de embarcação e arte de pesca), do pesqueiro utilizado e da época do ano. Na maior parte dos casos, não encontramos diferenças nos rendimentos de 2012 e 2013. As informações técnicas geradas são importantes para subsidiar ações de ordenamento pesqueiro, bem como para avaliar futuras mudanças que possam ocorrer na atividade frente à construção da barragem de Belo Monte no Rio Xingu.Palavras-chave: produção pesqueira, pescadores, esforço de pesca, rendimentos pesqueiros.

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