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The organization of fisheries in the Amazon region is an important theme, since the current management model is based mainly on the closed fishing season policy. This strategy suspends the catching of specific fish stocks and provides subsidies to professional fishers. Thus, the present study analyzed, through mathematical modeling, the behavioral interfaces of illegal fisheries that occurred between 1992 to 2017 in the Amazon basin, considering the hydrological seasonality and the effect of the presence or absence of the Closed Fishing Season law (CFSL). The data were tabulated and used for the construction of two illegal fishing scenarios. The first showed negative impacts with the absence of the CFSL, indicated by the high number of seizures of illegal catches that occurred during the period in which river water level is rising and showed continued growth over time. However, the second scenario showed apprehension apexes occurring at the beginning of the high-water level and at beginning of the low water level, with a continuous decrease in the seizures of illegal catches due to the new law. Thus, the ecosystem model constructed is a promising instrument for testing hypotheses and for formulating and monitoring management scenarios for fisheries in the region.

The execution of a reservoir for the production of electric energy substantially affects the daily lives of the populations living in the area, mainly those of the fishers who exploit the fishing resources in the barred river. Nevertheless, these populations and the impact on them have been little considered in the decision making on the construction of the dam. Currently, commercial fishing is of great importance for the population living around the Balbina reservoir, built 30 years ago. However, the information regarding the activity is still incipient. The objective of this study is to identify the structural and socioeconomic aspects of commercial fishing of the peacock bass Cichla vazzoleri, in order to contribute to the reservoir fishery management. Semi-structured interviews were carried out with sixty fishers. They answered questions about their socioeconomic aspects and about the fishing of the peacock bass C. vazzoleri, the main exploited species. The results showed that most of the fishers were male, and few reported being under 30 years old. Their level of education was low, and everyone was affiliated with some Fishers’ Association. The most used fishing gear was the hand-line. Throughout the year, fishers made only one trip per week. The fishing effort varied relatively little between flood and dry seasons or between localities. The average revenue per fishery in the Rumo Certo in the flood season was R$ 281.85 (± 134.05), and R$ 190.30 (± 160.56) in the dry season. In Balbina, the average revenue per fishery was R$ 404.45 (± 237.94) in the flood and R$ 299.66 (± 151.11) in the dry season. The fishers owned the small boats and fishing gear that were employed in the activity, and they financed their fisheries themselves. However, it was observed that income supplementation was very important, because the income from fishing was low and variable, being subject to the seasonal behavior of the reservoir level and the market price established by the commercial intermediaries.

Made available in DSpace on 2018-11-26T17:45:04Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-01-24 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) State of Amazonas Research Foundation through PRONEX Fishing is a traditional and important activity in the Amazon Basin, mainly for low-income populations. Nevertheless, Amazonian fish diversity and abundance is threatened by several anthropogenic sources, including deforestation, hydroelectric dams, oil and gas development, global changes and overfishing. This article analyzes the proposal of an alternative model and discusses the predictions obtained from various scenarios and relates them to the management of commercial fishing in the region of the middle Negro River. The model was developed using Stella (R) 9.0, a software package based on system dynamics. Two scenarios were simulated to investigate the dynamics of the fish stock: (a) scenario I: considered a reduction in stock replacement values to half the initial values, a 50% increase in fishing effort, and variable costs and average monthly prices of fish, and; (B) scenario II: analyzed the effect of prohibiting commercial fishing. The planning horizon used was 120 months. Given the results achieved by the simulations, it would be interesting for authorities in the region to have effective control over fishing access and for users to be aware that these natural resources, even though renewable, are susceptible to depletion. (C) 2017 Elsevier B.V. All rights reserved. Univ Fed Amazonas, Fac Ciencias Agr, Dept Ciencias Pesqueiras, Campus Univ,Av Gen Rodrigo Octavio Jordao Ramos, BR-69077000 Manaus, AM, Brazil Univ Estadual Paulista, Fac Ciencias Agr, Dept Engn Rural, Rua Jose Barbosa de Barros 1780, BR-18610307 Botucatu, SP, Brazil Univ Estadual Paulista, Fac Ciencias Agr, Dept Engn Rural, Rua Jose Barbosa de Barros 1780, BR-18610307 Botucatu, SP, Brazil State of Amazonas Research Foundation through PRONEX: 062.01053/2011

Este estudo teve como objetivo compreender as rela��es do regime fluvial do rio Purus com a pesca comercial e simular efeitos at�picos no n�vel deste rio. Foi realizado um levantamento de dados secund�rios referentes ao n�vel do rio Purus e a pesca comercial nesse ambiente e posteriormente, as informa��es adquiridas alimentaram o modelo constru�do no software Stella vers�o 8.0. Cada vari�vel foi representada por um s�mbolo, onde foram inseridas as rela��es funcionais que consistiram em constantes, par�metros, equa��es matem�ticas determin�sticas, gr�ficas e l�gicas. Foram simulados dois cen�rios: i) com varia��es do n�vel do rio consideradas normais. No qual, os resultados mostraram que houve a influ�ncia direta do regime fluvial na atividade pesqueira, dessa forma altera��es que podem ocorrer, causam impacto sobre a pesca; ii) com varia��es at�picas no n�vel do rio. Neste, foi observado um elevado aumento e oscila��o do esfor�o pesqueiro. A compara��o entre os dois cen�rios mostrou que, possivelmente, o aumento de oscila��es at�picas no regime fluvial prejudicar� os pescadores e os consumidores de pescado.

Made available in DSpace on 2016-09-23T15:11:51Z (GMT). No. of bitstreams: 1 PIB-B-033-2010.pdf: 547942 bytes, checksum: 022648782e3ae8d195e70d40adcd21d1 (MD5) Previous issue date: 2011-07-01 CNPQ A arraia Potamotrygon aff. histrix é endêmica da bacia do rio Negro. Habita preferencialmente as águas ácidas dos igapós com folhiços submersos, e ocasionalmente é capturada nos rios Demini e Branco. Com base nas diferenças físico-químicas entre os rios Negro e Branco, a hipótese da barreira hidrográfica do rio Branco será investigada do ponto vista osmorregulatório. Para tanto, exemplares de Potamotrygon sp. (arraia cururu) serão capturadas no rio Negro e serão expostos às águas do rio Branco. Após isso, os íons Na+, K+, Ca+2 e Cl-, além da uréia e osmolalidade serão analisados no plasma. Os resultados serão interpretados com base na teoria da barreia hidrológica, na qual os rios com características físicas e químicas distintas agem como barreiras delimitando a distribuição geográfica das espécies.

Made available in DSpace on 2016-09-23T15:11:55Z (GMT). No. of bitstreams: 1 R_F_B_53_2010.pdf: 1173838 bytes, checksum: a2ffbec92e043bc0cd3f146fe4999f29 (MD5) Previous issue date: 2011-07-01 CNPQ As arraias de água doce que evoluíram de ancestrais marinhos vivem em habitats estenohalinos nas grandes bacias hidrográficas sul-americanas com salinidade