Mamanguape River Research Articles

Artisanal fishermen knowledge on the avifauna composition in estuaries from Paraíba State: a contribution for conservation

Studies on animal diversity and ecology provide practical information necessary for the conservation and management of ecosystems, and can indicate contamination pathways as well as environmental transformations. However, avifauna studies in such endangered environments as mangroves are not very common. In an ethnoornithological context, this work has evaluated the knowledge of the local population in relation to the composition of avifauna in estuaries of Paraíba River and Mamanguape River, in state of Paraíba. Ethnobiological methods, together with estimative of species richness methods and comparisons with similarity tests, were used to demonstrate how the avifauna recorded for area was known by local population. Informers have mentioned 94 species of birds. Coefficients of Jaccard and Sorensen, with values of 0.617 and 0.763 respectively, demonstrate a considerable similarity between the composition of the avifauna known by the local population and the one recorded. Distribution of the knowledge was evaluated in relation to the communities’ social aspects. The results and methodology employed have expressed contributions and discussions about practical evaluations for conservation.

The interference of methods in the collection of teredinids (Mollusca, Bivalvia) in mangrove habitats

In the estuary of the Mamanguape River (Paraíba, Brazil), a new collection technique was developed and applied with virgin poles of mangrove trees Avicennia schaueriana (Verbenaceae), Rhizophora mangle (Rhizophoraceae), and Laguncularia racemosa (Combretaceae), taking into account wood preference, water salinity and depth influence during teredinid larval settlement. Sets of poles were vertically fixed in the riverbed at three sites along a decreasing salinity gradient, where they stayed for four months. The poles were collected and divided into upper, median, and lower segments, in agreement with different immersion regimes. An increase of 239% was obtained in the number of individuals when compared to a previous study in the same area using a different methodology. The species Teredo bartschi (Clapp, 1923), Nausitora fusticula (Jeffreys, 1860) and Bankia fimbriatula Moll & Roch, 1931 were registered in both studies, and the species Psiloteredo healdi (Bartsch, 1931) is here registered for the first time as occurring in that estuary. The species Neoteredo reynei (Bartsch, 1920), previously registered on tree branches of the mangrove habitat, was not found in the present work. Bankia fimbriatula, the most abundant species, did not show preference for any substratum but occurred significantly on the lower segment of the poles. N. fusticula, second in abundance, preferred to settle on poles of A. schaueriana and on any of the three segments. Aiming to assess the habitat variations, a more accurate study on teredinids diversity in mangrove ecosystems should be performed through a concomitant analysis from tree branches of the mangrove habitat, as well as from poles of mangrove trees or panels made of pine wood or mangrove trees wood. These collection devices should be maintained along a decreasing salinity gradient exposed to different tide levels.

Population Structure of The Mangrove Crab Ucides cordatus (Crustacea: Decapoda; Brachyura) in the Estuary of the Mamanguape River, Northeast Brazil.

The crab Ucides cordatus (Linnaeus, 1763) or ‘caranguejo-uçá’, as it is known in Brazil, is one of the most conspicuous and abundant components of the epibenthic macrofauna of Brazilian mangrove ecosystems and the most exploited resource by riparian human populations. It is aimed here to study the population structure of this crustacean in the estuary of the Mamanguape river, State of Paraíba, Northeast Brazil. The research was performed between August 2000 and September 2001. An area of 1600m2 was marked out through the mangrove habitat and the density of U. cordatus was determined by counting inhabited burrows. Three-hundred crabs were captured and biometrical and sexual ratio values were obtained. The mean density of inhabited burrows was 1.7 burrows m-2. Males crabs were larger than females and their sexual ratio was 1.85: 1.00. They mate between January and March. The low dimension of captured specimens and the low values of population density here obtained confirm the observation of crab gatherers that ‘caranguejo-uçá’ is decreasing in that mangrove area. It is suggested the need for a management plan aiming a sustainable exploitation of this important food and profitable resource. Key words: Ucides cordatus ⋅ Leaf-consuming crab ⋅ Mangrove ecosystem ⋅ Northeast Brazil

Distribution of wood-boring bivalves in the Mamanguape River estuary, Paraíba, Brazil

Wood-boring bivalves of the families Teredinidae and Pholadidae are reported for the first time in Paraíba State, north-east Brazil. During one year, molluscs were collected from mangrove tree logs and from wood panels, along a salinity gradient. Four teredinid (Neoteredo reynei, Teredo bartschi, Nausitora fusticula, Bankia fimbriatula) and one pholad species (Martesia striata) were found.