(Lamark, 1819) is an epibiont filter feeder bivalve. Its fast growth and fast gonadal recovery depend on the amount and quality of the food ingested by the animal, mainly composed of phytoplankton cells. In the coast of Paraná State, Brazil, several aquaculture farms of C. brasiliana can be found along the Paranaguá Estuarine Complex (PEC) and Guaratuba Bay. Therefore, this work had as objectives to evaluate the taxonomic composition and cell size of the microalgae ingested by adults of the oyster C. brasiliana and to describe its reproductive characteristics (index of meat revenue and stages of gonadal maturation). Oysters cultivated in the PEC were acquired monthly from the Municipal Market of Paranaguá. The oysters (n=30) were then measured and shell length values (SL), height (SH) and gross weight (GW) obtained. Gonadal maturation stages were evaluated through the macroscopic examination of the gonads and revenue index (R) through the wet weight of meat. The digestive gland was removed for the microscopic analysis of the stomach content (i.e. identification and measurement of the microalgae). The highest mean R value (12.79 %) was observed in July 2007, when a great portion of the population presented full gonads, although the predominance of individuals with full gonads (partially full and full) occurred in periods of warmer waters. The genera found in the digestive tract were: Nitzchia, Gyrosigma, Navicula, Pleurosigma, Thalassionema, Frustulia, Anomoeoneis, Chroococcus, Cocconeis, Diploneis, Cyclotella, Coscinodiscus and Prorocentrum, with the cell size varying from 5 to 260 µm.

No abstract

No abstract

Opsanus beta is endemic to the Gulf of Mexico and has recently been introduced to the Brazilian coast; probably the introduction is via ballast water and/or oil rigs. In this study, the presence of the species is recorded for the first time in Guaratuba Bay, on the southern coast of Brazil. In this region there are no port terminals, which suggests that O. beta used a different mode of human‐facilitated transport to colonize Guaratuba Bay.