A study of the fish community structure in a tidal creek

Spatial and temporal distribution patterns of the silver mojarra Eucinostomus argenteus (Perciformes: Gerreidae) in a tropical semi-enclosed bay

This study determined the spatial and temporal distributions of the silver mojarra Eucinostomus argenteus (Perciformes: Gerreidae), one of the most abundant teleost species in bays and estuaries. Sampling was conducted from July 2005 to June 2007. The species was captured on all sampling dates and at six of the seven sampling stations. Approximately 80% of the individuals were below the size of first sexual maturity (12·0 cm total length, LT ). Although the spatial distribution of juveniles and adults differed throughout the study period, the environmental variables measured explained only a small part of their distribution. The recruitment period occurred during the first part of each year. Despite the high pollution levels in Guanabara Bay, this coastal system plays an important role as a nursery ground and for the growth of E. argenteus.

Fishes of Paranaguá Estuarine Complex, South West Atlantic

The objective of this work was to present an updated checklist of the currently known fishes in the Paranaguá Estuarine Complex (PEC) and provides comments on conservation status for the treated species. We used a large dataset derived from a pool of studies which have been conducted within there along the last 30 years. Each study was based on monthly samplings and conducted in several estuarine habitat; thus, the pool covers practically all estuarine habitats and takes into account the seasonal cycle in the system. The PEC ichthyofauna represents a mixture between that fauna typical from the tropical Brazilian coast and that with affinities of temperate Argentinean and Uruguayan zones. The PEC harbors a rich fish fauna of 213 species, inserted in the families that are common along the Brazilian coast. Only a minor part (8%) of the PEC fish fauna was evaluated as regards the conservation status, mostly because of the lack of basic biological and ecological information for most species. Despite part of the among-estuaries differences are due to different and incomplete sampling efforts, the richness in the PEC is surprisingly higher than other systems in Brazil and around world, which emphasize the importance of the region for global biodiversity conservation.

Estrutura e organização trófica da ictiofauna de águas rasas em um estuário tropical

O presente estudo avaliou: 1) se a diversidade da ictiofauna de águas rasas do Rio Formoso (Pernambuco) varia entre as zonas estuarinas superior e inferior, e entre os períodos seco e chuvoso e 2) se houve diferenças espaciais e temporais nas categorias tróficas dessa ictiofauna. Os peixes foram coletados bimestralmente com rede-de-arrasto tipo mangote. Foram coletados 5475 indivíduos pertencentes a 78 espécies, sendo 51,3% de origem recifal. Carangidae e Gerreidae tiveram a maior riqueza específica, enquanto Clupeidae, Engraulidae e Gerreidae a maior abundância. Entre as espécies dominantes (89%), destaca-se Rhinosardinia amazonica (36%). A maioria da ictiofauna é predadora (75%) e com hábito alimentar carnívoro de 2ª. ordem (37,5%). A diversidade foi significativamente mais elevada na zona superior do estuário. A zona superior do estuário é, provavelmente, mais produtiva devido a sua maior complexidade morfológica, à maior abundância de Rhizophora mangle (abrigo e refúgio para vários peixes) e ao sedimento lamoso. O Fator de Contribuição Trófica (FCT) de detritos foi maior na zona estuarina superior, onde há maior teor de silte e argila. O FTC para a produção primária foi mais elevado na zona estuarina média, onde há uma maior biomassa fitoplanctônica. A maioria das espécies encontrava-se em ecofase jovem, evidenciando a importância das águas rasas deste estuário tropical como criadouro natural e abrigo para vários peixes de importância ecológica e econômica.