At the Sustainable Development Reserves of Mamirauá and Amanã, the pirarucu fishery is co-managed. Local fishermen assess pirarucu populations and, with the help of the Mamirauá Institute and state government, use this information to establish fishing quotas. Surveys are possible by counts of individual coming to the surface to breath air. This study reports preliminary findings of pirarucu population densities in the areas within the reserves based on the time series built in the last years and on satellite im agery of the managed area. The populations of the pirarucu increased in most managed areas. The increase rates for each managed area relative to the last year for which data are available are: Jarauá (562.881 km 2) 525%, Tijuaca (248.293 km 2) 169%, M araã/Lago Preto (18.53 km ²) 1039%, and Coraci (410.340 km 2) 20%. The data suggests that the management for conservation of pirarucus within the reserve is effective. In part, that is so due to the fact that the management is participatory and carried out in an adaptive strategy.

A pesca é atividade essencial para as comunidades ribeirinhas da Amazônia, sendo o peixe fonte primordial de proteína animal e importante componente na geração de renda. Devido às variações na abundância e distribuição das espécies de peixe como conseqüência do ciclo hidrológico na região, ocorre sazonalidade na atividade de pesca. Assim, este estudo teve por objetivo identi car quais fatores determinam o tempo de dedicação às pescarias de subsistência ou com ns comerciais, por ribeirinhos de áreas de várzea. Foram entrevistados 244 pescadores de 16 comunidades no Baixo Solimões, quanti cados os volumes capturados de tipos de pescado, por período do ano (seca ou cheia), e identi cados os ambientes de pesca, os aparelhos utilizados e a receita bruta gerada quando da venda do pescado. Os resultados mostraram que há tendência no aumento do número de pescadores comerciais à medida que se aproxima do centro urbano de Manacapuru, sendo dois os fatores determinantes da atividade pesqueira praticada com este m: ambientais, pela disponibilidade e acesso à áreas de pesca, e econômicos, estimulada a venda do peixe pela proximidade de centros de comercialização, o que gera o envolvimento de maior número de agentes na pesca. Os igapós foram importantes para todas as comunidades, sendo os ambientes mais explorados no período de cheia para captura de pescado, fato que ressalta a importância de medidas para sua conservação.

Humid highland forest enclaves are remnants of Atlantic Forest found in tablelands within the Caatinga biome (Northeastern Brazil), which emerged during interglacial periods in the Pleistocene. These ecosystems have a highly diverse and endemic fish fauna. Most earlier surveys have focused on the tableland of Borborema (Pernambuco and Paraíba States). In this study we surveyed the fish fauna of the humid forest enclaves in the tablelands of Ibiapaba and Araripe, based on samples collected in the rainy season (March and April) between 2009 and 2014. The 45 sampling points covered rivers, streams and reservoirs in five river basins belonging to three ecoregions. The species were listed according to drainage divide, and endemism was determined for each ecoregion and for the Caatinga. Our area was more species-rich (n=59) than Borborema (n=27). The samples included five introduced species and 29 species endemic to the Caatinga (49.1% of the sampled species). The distribution of Parotocinclus haroldoi was expanded to the Mid-Northeastern Caatinga ecoregion (Timonha river basin, Ceará State). Our study intends to make a significant contribution to current knowledge of the ichthyofauna in humid highland forest enclaves of semiarid Northeastern Brazil, identified as a priority in the conservation of the biodiversity in the Caatinga.

Tidepools are considered ecosystems of high interchangeable fish biota. However, natural and anthropogenic actions that alter negatively marine ecosystems functioning (e.g., algal exploitation) are causing homogenization of fish biodiversity. Here, we describe the functional and taxonomic assembling of fishes in beach rocks of northeastern Brazil. Traits of fish species were retrieved from Fishbase and beta diversity was assessed by the dispersion of abundance, presence-absence and functional diversity in the multivariate space. We explained spatial-temporal variation in: alpha diversity, taxonomic and functional community composition; as well as temporal variation in functional, beta and gamma diversities. We found an annual stability in fish diversity and composition, and that fish biota was assembled mainly per tidepools' depths. Substrate heterogeneity was correlated to depth, highlighting the role of local features as filters to organize the fish fauna vertically in tidepools, especially a cultivation of algae that influences the local assembling. We also highlight the uniqueness status of beach rocks in the Brazilian tropical region.

Several hypotheses are used to explain species richness patterns. Some of them (e.g. species-area, species-energy, environment-energy, water-energy, terrestrial primary productivity, environmental spatial heterogeneity, and climatic heterogeneity) are known to explain species richness patterns of terrestrial organisms, especially when they are combined. For aquatic organisms, however, it is unclear if these hypotheses can be useful to explain for these purposes. Therefore, we used a selection model approach to assess the predictive capacity of such hypotheses, and to determine which of them (combined or not) would be the most appropriate to explain the fish species distribution in small Brazilian streams. We perform the Akaike’s information criteria for models selections and the eigenvector analysis to control the special autocorrelation. The spatial structure was equal to 0.453, Moran’s I, and require 11 spatial filters. All models were significant and had adjustments ranging from 0.370 to 0.416 with strong spatial component (ranging from 0.226 to 0.369) and low adjustments for environmental data (ranging from 0.001 to 0.119) We obtained two groups of hypothesis are able to explain the richness pattern (1) water-energy, temporal productivity-heterogeneity (AIC = 4498.800) and (2) water-energy, temporal productivity-heterogeneity and area (AIC = 4500.400). We conclude that the fish richness patterns in small Brazilian streams are better explained by a combination of Water-Energy + Productivity + Temporal Heterogeneity hypotheses and not by just one.