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This study investigated the importance of variations in environmental factors affecting the abundance patterns of decapods on the southeastern Brazilian coast. Sampling was carried out monthly from January 1998 through December 1999 in Ubatumirim and Mar Virado, Ubatuba region, using a commercial shrimp fishing boat equipped with double-rig nets. Six areas adjacent to rocky shores were chosen. Bottom-water samples were collected using a Nansen bottle, to measure the temperature and salinity. Sediment samples were also obtained by means of a Van Veen grab, for determination of texture and organic-matter content. The association of environmental factors with species abundance was evaluated by Canonical Correspondence Analysis (α = 0.05). Forty-one species of Decapoda were used in the multivariate analysis. The analysis indicated that sediment texture (phi) and bottom temperature were the main factors correlated (p < 0.05) with the spatial and temporal abundance of the species. Considering the study region as faunal transition zone, including a mixture of species of both tropical and subantarctic origin, the species responded differently to environmental factors, mainly temperature. It is conceivable that the decapods adjust their distribution according to their intrinsic physiological limitations, possibly as a result of the available resources.

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-The evaluation of population characteristics, particularly those of endemic species, aids in population preservation and management. Hermit crabs present an innate behavior of occupying shells, which tends to individual needs and limits their distribution. This study characterized the pattern of occupation of gastropod shells by the hermit Loxopagurus loxochelis in three bays of the southwestern coast of Brazil. Monthly collections were made from January/1998 to December/1999 in the bays Ubatumirim (UBM), Ubatuba (UBA) and Mar Virado (MV) with a shrimping boat. Overall, ten species of gastropod shells were occupied by L. loxochelis. The shell of Olivancillaria urceus represented 66.8% of those occupied. Morphometric relationships demonstrated a differential occupation of the more abundant shells among demographic groups, where most of the males occupied O. urceus, non-ovigerous females occupied O. urceus and Buccinanops cochlidium, and ovigerous females occupied B. cochlidium and Stramonita haemastoma. Most of the individuals occupied the more abundant shells, considered adequate for the morphology of this hermit crab species. Thus, the studied bays seem to be stable and propitious environments for population perpetuation and the settlement of new individuals.

The present study assessed the composition and abundance of species of Anomura at the southeastern coast of Brazil. Sampling was carried out monthly from January 1998 to December 1999, in three regions of Ubatuba: Ubatumirim Bay, Ubatuba Bay and Mar Virado Bay, using a fishing boat equipped with two double-rigged nets. Four transects were defined at depths of 5, 10, 15, and 20 meters in each bay. Two additional transects were defined perpendicular to the beach: one in a sheltered area and the other in an area exposed to wave action. A total of 6356 specimens of anomurans representing 15 species and 9 genera of 3 superfamilies (11 Paguroidea, 1 Hippoidea, and 3 Galatheoidea) was recorded. Paguristes robustus was recorded for the first time from the São Paulo State coast. Dardanus insignis was the most abundant species, followed by Loxopagurus loxochelis and Porcellana sayana. The high abundance of P. sayana may be related to the presence of D. insignis and Petrochirus diogenes, because this porcellanid crab lives inside the shells occupied by these hermit crabs. Species richness varied among the bays and transects, but the highest values were observed at the exposed and sheltered areas. The highest abundance of anomurans was recorded at a depth of 20 m during winter in the bays Mar Virado and Ubatuba. The anomuran species comprised 75% of the total number previously recorded from coastal non-consolidated bottoms of São Paulo. We therefore infer that this region affords favourable biotic and abiotic conditions for the settlement and maintenance of a large number of species of Anomura. RESUMO

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This study analyzed the size at sexual maturity and reproductive period of populations of Hepatus pudibundus in three bays on the northern coast of São Paulo, Brazil. Crabs were collected monthly and the bottom-water temperature was measured at each collection point. The animals were sexed, measured for carapace width (CW), and their gonadal stages were determined. A total of 8,674 specimens were collected (2,435 males and 6,239 females). Adult males showed the highest mean CW; the size at maturity for both sexes was 32.5 mm CW. Reproduction was continuous and peaked in spring and summer, because of the greater availability of plankton food for the larvae. This pattern is typical in tropical and subtropical regions, unlike the seasonal reproduction found in temperate regions. Reproductive activity of females was not significantly correlated with bottom-water temperatures. Immatures and individuals in all stages of gonadal development were found throughout the sampling period and at all depths, probably because the species completes its entire reproductive cycle in that area.