Macrobrachium amazonicum is the most frequently consumed freshwater crustacean by river communities of the Amazon. Despite its relative abundance and vast knowledge on the species from data on cultivated specimens, little is known regarding its biology in the natural environment, especially its use of creeks that are strongly influenced by the tide. Specimens of Macrobrachium amazonicum were collected in September 2006 (dry season) and March 2007 (rainy season) from two perennial creeks of the Guajará Bay in the state of Pará (northern Brazil), using traps similar to the matapis used by local fishermen to identify the spatial distribution of the species. Shrimps of all sizes use the tidal creeks in both seasons, including for breeding purposes. The greatest abundance of the species occurred in headwater areas and in the dry season. It is suggested that abundant allochthonous organic matter and the preference for protected areas may explain the abundance and breeding activity of this species in the headwaters of the creeks.

Some morphometric relationships and biometric aspects were studied in the hermit crab Loxopagurus loxochelis (Moreira, 1901) with the purpose of describing its relative growth and finding the size where sexual maturity is reached. Specimens were collected monthly from September 1995 to August 1997 in the Ubatuba region using double-rig trawl nets. A total of 1084 specimens (625 males and 459 females) was analysed. In this species, sexual dimorphism is particularly evident in chela dimensions. Differences between males and females were found in the left propodus length versus cephalothoracic shield length (CSL) and wet weight (WW) versus CSL relationships. Males showed a high positive allometry in chela growth, while females were close to isometry/negative allometry. The size at which a clear differentiation occurred in the growth of the propodus length and in the increase in weight of males and females was between 4.5 and 6.0mm CSL, suggesting that size at which sexual maturity is reached.

"POPULATION STRUCTURE AND BREEDING SEASON OF THE SOUTH ATLANTIC HERMIT CRAB, LOXOPAGURUS LOXOCHELIS (ANOMURA, DIOGENIDAE) FROM THE UBATUBA REGION, BRAZIL" published on 01 Jan 2002 by Brill.

Although thalassinidean shrimps exert considerable influence over the structure of benthic communities no ecological studies have been conducted on the larvae and adults ofLepidophthalmus siriboiaandUpogebia vasqueziin the equatorial region. The aim of the present study was to identify the reproductive period of these species in an Amazonian estuary. Monthly collections were performed in the estuary of the Marapanim River (northern coast of Brazil) over the course of one year (August 2006 to July 2007) and adults were obtained from bare sandy substrate and between boulders in the intertidal zone of the estuary at four sites. Thalassinidean larvae were also sorted from plankton samples (200 μm mesh) collected monthly at six sites. Larvae of the speciesCallichirus major, Lepidophthalmus siriboiaandUpogebia vasqueziwere collected, whereas adults of only the latter two species were found.Upogebia vasqueziwas the most abundant species. There was no correlation between larval density and abiotic factors (water temperature, salinity and pH); however, the density ofU. vasqueziadults was negatively correlated with salinity in the burrows.Lepidophthalmus siriboiaandU. vasquezireproduce throughout the year in the Marapanim River estuary, with peaks of greater intensity in some reproductive periods of the year, mainly correlated with changes in salinity.

Shrimp trawl fisheries constitute a major threat to continental shelves' biodiversity, given their profound impact on benthic communities. We investigated the composition of an invertebrate assemblage impacted by this type of fishery and possible correlations of the abundance and richness with specific environmental parameters. The activities of the industrial shrimp fleet on the north coast of Brazil were monitored over two years. We analyzed 20,303 specimens belonging to seven phyla (Porifera, Cnidaria, Mollusca, Sipuncula, Annelida, Arthropoda, Echinodermata) and 154 species. There was a predominance of generalist and rare species, given that most species (86) were sporadic. Taxonomic composition patterns were complex, dynamic, and were correlated mainly with the temperature and depth of the Amazon continental shelf, the largest in extension and low depth of the South Atlantic. The crustaceans were dominant in both abundance and taxonomic richness. The influence of environmental factors on the abundance of the main species is discussed. The invertebrates are a neglected component in studies of fisheries impact and important components of the ecological structure of the Amazon coast. They are an essential group for developing a holistic fisheries management approach, which will support the sustainability of the region's fisheries and preserve local aquatic communities.

The development stages of male and female gonads in the freshwater crab Sylviocarcinus pictus (H. Milne Eduards, 1853) were described through macroscopic and microscopic (histology) examinations. The histological description was based on 40 specimens (20 each sex). Four gonadal development stages were found for females: immature, ripening, mature and spawned. The following female cells were found: ovogonia, oocytes in initial vitellogenesis, oocytes in advanced vitellogenesis, follicular cells and post-ovulatory follicles. Three development stages were found for males: immature, maturing and mature, with the indication of: spermatogonia, spermatocytes, spermatids, spermatozoids and spermatophores. These data suggest the pattern described in the literature. Size at sexual maturity was 32.3 mm of carapace width for males and 31.5 mm for females. The gonadal stages observed macroscopically by volume and color were validated through histological analysis and proved to be useful method for the rapid identification of sexual maturity in the species. The present study offers previously unpublished data on the reproductive biology of Sylviocarcinus pictus.