BackgroundAcquiring fast and accurate information on ecological patterns of fishery resources is a basic first step for their management. However, some countries may lack the technical and/or the financial means to undergo traditional scientific samplings to get such information; therefore affordable and reliable alternatives need to be sought.MethodsWe compared two different approaches to identify occurrence patterns and catch for three main fish species caught with bottom-set gillnets used by artisanal fishers from northeast Brazil: (1) scientific on-board record data of small-scale fleet (n = 72 trips), and (2) interviews with small-scale fishers on Local Ecological Knowledge (LEK) (n = 32 interviews). We correlated (Pearson correlations) the months cited by fishers (LEK) as belonging to the rainy or to the dry season with observed periods of higher and lower precipitation (SK). The presence of the three main fish species at different depths was compared between LEK and SK by Spearman correlations. Spearman correlations were also used to compare the depths of greatest abundance (with the highest Capture per Unit Effort - CPUE) of these species; the CPUEs were descendly ordered.ResultsBoth methods provided similar and complementary bathymetric patterns of species occurrence and catch. The largest catches occured in deeper areas, which also happened to be less intensively fished. The preference for fishing in shallower and less productive areas was mostly due to environmental factors, such as weaker currents and less drifting algae at such depths.ConclusionBoth on-board and interview methods were accurate and brought complementary information, even though fishers provided faster data when compared to scientific on-board observations. When time and funding are not limited, integrative approaches such as the one presented here are likely the best option to obtain information, otherwise fishers’ LEK could be a better choice for when a compromise between speed, reliability and cost needs to be reached.Electronic supplementary materialThe online version of this article (doi:10.1186/s13002-017-0156-9) contains supplementary material, which is available to authorized users.

approximately 10 km) from the Patos Lagoon's jetties. The composition and dominance of the fish community of the surf zone of Cassino Beach changed little in the latest 20 years, indicating a possible stability of the system.]]>

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Resumo Uma vez que os leitos de drenagem / secagem com manta geotêxtil têm apresentado resultados promissores no tratamento de lodos de decantadores de ETAs no Brasil, esse estudo avaliou esta técnica em protótipos de escala reduzida e piloto, considerando, além de parâmetros de projeto, aspectos quantitativos e qualitativos do drenados e tortas de lodo produzidos. Pode-se constatar que, para o lodo de estudo, a manta de 600 g.m-2 com taxa de aplicação de sólidos-TAS da ordem de 3,0 kg.m-2 apresentou melhor desempenho. A fase de secagem nos ensaios em escala piloto foi favorecida, resultando na extinção da lâmina líquida em 1 dia e teor de sólidos totais após 7 dias de 18,3 %-teores da mesma ordem de grandeza que as obtidas em técnicas mecânicas. O teste de toxicidade com Artemia salina para o lodo inicial apresentou maior toxicidade, evidenciando a eficácia do sistema de desaguamento. Palavras-chave: Lodo de decantadores de ETA, taxa de aplicação de sólidos, escalas reduzida e piloto, toxicidade.

In 2019 an oil spill spread over more than 4000 km of the Brazilian coastline.Monitoring programs that allow for the evaluation of potential impacts on communities and ecosystems and their recovery through time are needed and rely on baseline information previous to the oil spill. Here we compiled qualitative and quantitative data available from 8 studies on fi sh and benthic species from different habitats of Rio Grande do Norte (RN) from 2007 to 2018. We assessed the number of species from different locations and compiled information on conservation status and human use. We mapped the study areas and habitats and overlapped them with those affected by the oil spill. The RN state has a high diversity of fi sh (175 species) and benthic species (285 species), of which more than half of fi sh (52%) and 2% of benthic species are threatened and 72,8% of fi sh and 7,9% of benthic species are of commercial interest. Information of most habitats is still poorly known (i.e.majority ofthe available data are from unique and punctual sampling), which may weaken future evaluations of the real impact of the oil spill. Nonetheless, it is possible to design reliable monitoring based on our dataset, persistent contamination and future loss of diversity.