18 research outputs found
O uso de rĂ©plica no estudo da ictiofauna de uma planĂcie de marĂ©
Em uma planĂcie de marĂ©, a anĂĄlise comparativa das capturas mensais
de peixes, obtidas em dois arrastos consecutivos com uma rede
do tipo picaré, não revelou ao longo do ano, diferenças significativas
entre amostragens. Este foi considerado um forte indĂcio de que a assemblĂ©ia
de peixes capturada foi a mesma em ambos os arrastos.
ABSTRACT
Comparative analysis of monthly samples obtained with two drags
of a seine net in a tidal flat, did not indicate significantly differences
between drags, indicating that the same fish assemblage was sampled.
RĂSUMĂ
Dans un bassin inondé par la marée, lanalyse comparée des captures
mensuelles de poissons, obtenues par deux coups consécutifs avec
une seine de plage, na pas montré des différences significatives au cours
de lannĂ©e, montrant ainsi que cest le mĂȘme assemblage de poissons
qui a été échantillonné
Fishes collected with an artisanal fish trap in Barra de Camaratuba estuary, northeastern Brazil
A list of the species of fishes collected in the Barra de Camaratuba estuary, Paraiba, Brazil, is presented.Specimens were collected on a monthly basis between January and December 2012, using a fishing technique known locally as âTomadaâ, an artisanal fish trap like a barrier. Forty species were collected, belonging to 27 genera and 20 families of the Teleostei. The Gerreidae was the most representative family, with 6 species, followed by the Lutjanidae and Tetraodontidae, with four species each
Fishes collected with an artisanal fish trap in Barra de Camaratuba estuary, northeastern Brazil
A list of the species of fishes collected in the Barra de Camaratuba estuary, Paraiba, Brazil, is presented.Specimens were collected on a monthly basis between January and December 2012, using a fishing technique known locally as âTomadaâ, an artisanal fish trap like a barrier. Forty species were collected, belonging to 27 genera and 20 families of the Teleostei. The Gerreidae was the most representative family, with 6 species, followed by the Lutjanidae and Tetraodontidae, with four species each
Environmental and subtidal fish assemblage relationships in two different brazilian coastal estuaries
The general structure and organization of the shallow water (<1.5 m) fish assemblages were studied in two southern Brazilian ecosystems, a bay and a lagoon, under different marine or continental influences. The abiotic factors were measured to define the hydrology of the sites and the biotic descriptors were evaluated to characterize the assemblage structures. Transparency, salinity and organic matter were the abiotic factors which best distinguished the sites. A total richness of 69 species was observed. Ecological guilds, density, diversity and evenness indices values were different at each site. The hydrodynamism and geomorphology determined the structure and the organization of the fish assemblages in these shallow waters. It was observed that the variations in the hydrological attributes generated by the marine or continental water movements were able to alter the conditions in the lagoon more quickly and at more regular frequencies than those in the bay
Structure and Dynamics of Fish Assemblages in a Tidal Creek Environment
Studies were carried out on structure and dynamics of fish assemblages in the Baguaçu tidal creek, Paranaguå Bay, Brazil. A total of 30,104 fish were captured, comprising 21 families and 47 species. Both in weight and in number, the species Anchoa parva prevailed. Monthly captures in number and weight were largest in the autumn and part of the winter. No seasonal tendency was observed in the indexes of community structure. The dendrogram produced by the classification of the samples separated the 12 months of collection into three groups, reflecting differences in the qualitative and quantitative occurrences of the most important taxa. Some ecological likeness, not only seasonal patterns of abundance, seemed evident in the seasonality of the groupings of species revealed through the cluster analysis. The principal component analysis reflected mainly the periods of rain and drough
Fish assemblages in a tidal flat
Studies were carried out on fish assemblages in a tidal flat. Samples were obtained monthly at low tide of the half moon in the tidal flat of ParanaguĂĄ Bay, Brazil, with two seine nets, one with a 1 mm mesh, 30 m in length and 3 m in height and another with a 10 mm mesh, 65 m in length and 2 m in height. A total of 8,890 fish were captured, comprising 24 families and 53 species. The most abundant species were Harengula clupeola and Atherinella brasiliensis, which represented 63.4% of the total, capture. A seasonal tendency was observed in the abundance of fishes, with less fishes being captured during winter and part of spring. The number of species showed a seasonal pattern, with the gradual decrease through winter and a marked increase in summer. The community structure index indicated seasonal changes in the assemblage. The faunistic similarities between months separated the 12 months into four major groups. The seasonal pattern was apparent in the numerically dominant species and the Cluster Analysis revealed five main groups
Introducing fuzzy set theory to evaluate risk of misclassification of land cover maps to land mapping applications: Testing on coastal watersheds
In land cover maps, categories represent a continuum of variation and for this reason, fuzzy set theory, which
accepts degrees of membership, has been suggested for land classification. Nevertheless, classical set theory,
which only assumes single map categories, is still widely used. The purpose of this study is to develop a
methodology to reduce the weakness of land cover maps in which classical theory has been applied. To do so, we
propose adding an error relevance step after accuracy assessment, which evaluates how relevant are the classification errors to selected land applications. First, a membership matrix is built based on a linguistic scale
associated to land cover rates obtained from literature. Then, two fuzzy measures are calculated and the frequency of categories, that do not pose a problem to the user in light of the land application, is determined. The
methodology is demonstrated using two Brazilian tropical coastal regions and two land applications relevant for
coastal watershed management. The study presents land cover maps of the Mamanguape and the ParaĂba estuarine regions, their full accuracy assessment, and the relevance of the classification errors to the land applications.
The accuracy assessment step has demonstrated that the land cover maps are reliable. The error relevance
step has shown that the map weakness can be reduced. Both steps show that the land cover maps produced are
suitable for further land mapping applications. The results on land cover composition point to the importance of
future work focused on the environmental sustainability of the studied regions. The new procedure has proven
useful to decrease the degree of distrust with which land cover maps are regarded. The framework provided is
suitable for virtually any land mapping application.AD1D-1E23-B6C4 | Zara Fani Gonçalves TeixeiraN/