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.Keywords: creek, Macrobrachium, Amazon River prawn, estuary.Distribuição espacial do camarão-da-amazônia -Macrobrachium Amazonicum (Heller, 1862) (Decapoda, Caridea, Palaemonidae) em dois canais perenes de um estuário da costa norte do Brasil (Baía do Guajará -Belém, Pará, Brasil) ResumoMacrobrachium amazonicum é o crustáceo dulcícola mais frequentemente consumido pelas populações ribeirinhas da Amazônia. Entretanto, apesar de sua relativa abundância e vasto conhecimento da espécie a partir de dados de cultivo, pouco se conhece sobre sua biologia no ambiente natural, especialmente quanto à forma de utilização de canais fortemente influenciados pelas marés. Amostras desse camarão foram coletadas em setembro/06 (período seco) e março/07 (período chuvoso), em dois canais perenes da Baía do Guajará, Pará, utilizando armadilhas (matapis) como as utilizadas pelos pescadores locais para identificar a distribuição espacial dos organismos. Os canais de maré são utilizados por camarões de todos os tamanhos nas duas estações do ano, inclusive para a reprodução. A maior abundância de indivíduos da espécie foi encontrada no período seco, nas áreas a montante dos canais . Postula-se que a abundante matéria orgânica alóctone e a busca de locais protegidos podem ser os fatores que explicam a concentração da abundância e da atividade reprodutiva nas áreas a montante dos canais.Palavra-chave: canais de maré, Macrobrachium, camarão-da-amazônia, estuário.

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Although thalassinidean shrimps exert considerable influence over the structure of benthic communities no ecological studies have been conducted on the larvae and adults of Lepidophthalmus siriboia and Upogebia vasquezi in 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 mm mesh) collected monthly at six sites. Larvae of the species Callichirus major, Lepidophthalmus siriboia and Upogebia vasquezi were collected, whereas adults of only the latter two species were found. Upogebia vasquezi was the most abundant species. There was no correlation between larval density and abiotic factors (water temperature, salinity and pH); however, the density of U. vasquezi adults was negatively correlated with salinity in the burrows. Lepidophthalmus siriboia and U. vasquezi reproduce 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.

ResumoEste estudo realizou um levantamento dos casos notificados de malária no Estado do Pará entre 1998 e 2006, com intuito de quantificar o risco de transmissão da doença, discriminar o número de casos por espécies de Plasmodium e destacar as áreas de maior incidência. Das 5.454.700 amostras sanguíneas examinadas, a positividade foi de 27,58% (22,38% Plasmodium falciparum; 76,11% Plasmodium vivax; 0,31% Plasmodium malariae e 1,20% infecções mistas P. falciparum e P. vivax), sendo observada redução gradativa de notificações a partir de 2001. Além disso, constatou-se que sete municípios apresentaram incidência parasitária anual (IPA) alta entre 1998 e 2006 e outros 31 tiveram média dos nove anos de IPA≥50, sendo constatado aumento do número de municípios com IPA média e baixa. Em suma, o Estado do Pará apresentou redução significativa de casos notificados de malária, com tendência de aumento do número de municípios com IPA baixa e média, provavelmente reflexo das ações governamentais de controle e prevenção à malária na região.Palavras-chave: epidemiologia; malária; Plasmodium; Estado do Pará; Amazônia Brasileira. Summary The aim of this study was to carry out a survey of malaria cases reported in the state of Pará from 1998 to 2006 in order to quantify the risk of disease transmission, to discriminate the number of cases by

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A population of Loxopagurus loxochelis was studied in terms of seasonal abundance, size frequency distribution, sex ratio, and reproductive period (percentage of ovigerous females). Specimens were collected monthly over a period of two years (from September 1995 to August 1997) in the non-consolidated areas of the Ubatuba, Mar Virado, and Ubatumirim bays (northern coast of São Paulo State, Brazil) with a double-rig trawl net. A total of 1,084 individuals were analysed. Animal size (minimum, maximum, and mean § SD shield length) was 2.8, 9.1, and 6:88 § 1:13 mm for 625 males; 2.8, 8.2, and 5:78 §0:98 mm for 236 non-ovigerous females; and 4.6, 8.0, and 6:24 §0:68 mm for 223 ovigerous females, respectively. Sexual dimorphism was recorded by the presence of males in the largest size classes. The sex ratio was 1.4 : 1 in favour of males. The highest incidence of ovigerous females occurred during winter and spring (June to October), with a low percentage in summer and fall (November to May), indicating continuity in the reproductive cycle. This strategy of reproduction is related to temperature. The occurrence of L. loxochelis in the Ubatuba region represents the nal point of northern distribution of this species as a function of water mass in uence, and could be its real limit on the Atlantic coast of South America. 4 /

The present work was conducted to determine the distribution of Loxopagurus loxochelis collected monthly, over a period of one year, in Ubatuba Bay (from September/95 to August/96). A total of 179 specimens were collected (138 males, 30 females and 11 ovigerous females). The greatest depth, predominance of very fine sand and highest mean value of organic matter contents of sediment, in combination with the low temperatures registered in winter (July and August), determined the presence of L. loxochelis in the subarea located at the Ubatuba Bay mouth, exposed to the open sea with high water current energy, important because this position insures that spawned larvae will enter into the oceanic circulation.

Upogebia vasquezi inhabits the western Atlantic in the regions of southern Florida, the Bahamas, Central America and Brazil (from the States of Maranhão to São Paulo). Its occurrence has been extended to the coastal region of the State of Pará (northern Brazil). There are few descriptions of the larval development of the 116 known species of Upogebia. The present study offers the first description and illustrations of the first two larval stages (zoeas I and II) of U. vasquezi reared in laboratory. The larval features of U. vasquezi were compared with those of two other species of Upogebia, revealing very similar morphological characteristics among species in zoea I. The main variation in this larval stage was in the segmentation of the maxillulary endopod. In zoea II, the number of setae on the scaphognathite was different among some species of Upogebia. The present study contributes to the available literature on the identification of thalassinidean larvae.