This study was conducted in two estuarine inlets (Saco da Mangueira and Saco do Arraial) at the Patos Lagoon estuary, southern Brazil. The changes in relative abundance and size of post-larvae and juvenile shrimp Farfantepenaeus paulensis and juvenile blue crab Callinectes sapidus were compared, considering the influence of salinity and the presence of submerged seagrass meadows. The analyses were performed using generalized linear models (GLM) for abundance variations and ANOVA for variations on the size of individuals. The pink shrimp was more abundant at Saco da Mangueira, in seagrass meadows and areas of higher salinity. The blue crab was more abundant at Saco do Arraial and in lower levels of salinity. The importance of submerged vegetation for the blue crab lies in a preference of smaller crabs of the species for the seagrass meadows. It has been shown that these species choose different habitats in the estuary, and both the salinity and the presence of submerged seagrass meadows influence the selection of habitat.

O registro de Eurypanopeus depressus (Smith, 1869) na costa do Rio Grande do Sul, Brasil (Decapoda:Xanthidae) levanta a hipótese de que a espécie pode ser invasora, devido a diferentes fontes de introdução como água de lastro. E. depressus foi coletada com rede de portas no estuário da Lagoa dos Patos. A discussão foca no fato de que a distribuição primária da espécie na América do Sul pode ter sido na costa uruguaia, tendo esta posteriormente se irradiado para locais próximos (Brasil e Argentina). Este trabalho estende a distribuição da espécie no hemisfério sul, já que previamente era citada somente para a Argentina e Uruguai.

The discovery of Eurypanopeus depressus (Decapoda: Panopeidae; Smith, 1869) on the coast of Rio Grande do Sul, Brazil suggests that the species was recently introduced, possibly due to different sources of introduction, such as the ballast water of ships. E. depressus were collected using otter-trawl net in the Patos Lagoon Estuary. Discussion focuses on the fact that the primary South American distribution derives from Uruguayan shores, and later expanded to nearby places (Brazil and Argentina). This work extends the Southern Hemisphere distribution for the species, as it was previously reported only from Argentina to Uruguay.

Os experimentos foram realizados para investigar os efeitos da amônia, nitrito e nitrato no consumo alimentar de juvenis de Farfantepenaeus brasiliensis. Os camarões com peso médio de 4g foram aclimatados durante 28 dias em diferentes concentrações crônicas de amônia, nitrito e nitrato. Após o período de exposição de 28 dias, 20 camarões por tratamento foram individualizados em unidades experimentais de 3 L, a fim de ser analisado o consumo de ração em função da quantidade de alimento oferecido e as sobras durante um período de 24 horas. O consumo alimentar apresentou alterações significativas (P<0,05) para os camarões expostos às concentrações de nitrito e nitrato testadas, enquanto para o tratamento com amônia, os camarões não apresentaram alterações no consumo alimentar (P>0,05). Foi verificado que o nitrito e o nitrato afetam o consumo alimentar de F. brasiliensis. Contudo, a possibilidade de que isso ocorra durante longos períodos, afetando negativamente o cultivo de espécies em cativeiro, reforçam a necessidade do manejo da qualidade de água.

The experiments were carried out to investigate the effects of ammonia, nitrite and nitrate on food consumption of juvenile F. brasiliensis. The juvenile shrimp were acclimated for 28 days with different cronic concentrations of ammonia, nitrite and nitrate. After the acclimation period, 20 shrimps per treatment were individualized in 3 L experimental units in order to analyze their feed intake through the amount of feed offered and leftover for a period of 24 hours. The food consumption presented significant alteration (P<0.05) for the nitrite and nitrate concentrations tested, meanwhile on ammonia treatment, shrimp presented no alteration on food intake (P>0.05). According to the results obtained, nitrite and nitrate affected F. brasiliensis food consumption. However, the possibility of this to happen over long periods, can damage the species in captivity, reinforced the necessity of regular water quality management.

Natural diet of Neohelice granulata in two salt marshes of Lagoa dos Patos, RS were studied. Sampling was performed seasonally and crabs were captured by hand by three persons during one hour, fixed in formaldehyde (4%) during 24 h, transferred to alcohol (70%). Each foregut was weighed and repletion level was determined. Differences between sexes in the frequencies of occurrence of items were tested by χ2test. A total of 452 guts were analyzed. Quali-quantitative analyses were calculated following the method of relative frequency occurrence and relative frequency of the points. At both sites, for both sexes and in all seasons, the main food items were sediment, Spartina sp. and plant detritus. The highest values of mean repletion index were estimated for the spring and summer. Analysing both salt marshes, in different seasons significant shifts in the natural diet of Neohelice granulata was not observed throughout the period of study.

Devido à falta de estruturas rígidas para determinação de idade em crustáceos, métodos que se baseiam na determinação de idade através da distribuição da freqüência de comprimentos são comumente utilizados. Neste trabalho, foi comparado o crescimento do siri-azul, Callinectes sapidus Rathbun, 1896, em laboratório e a partir de indivíduos de campo. Os indivíduos de laboratório, após a coleta, tiveram seu crescimento acompanhado individualmente. A temperatura foi mantida constante (25±2°C) e a salinidade a 20±5. Os indivíduos do campo foram coletados entre 2002 e 2004 em pontos pré-determinados no estuário da Laguna dos Patos, com rede de portas. A biometria, nos dois casos, constou da medida da largura da carapaça (LC mm). As estimativas das curvas de crescimento, segundo o modelo de Bertalanffy para os indivíduos de campo, foram obtidas pelo acompanhamento do deslocamento modal (MPA). O tamanho máximo de largura de carapaça utilizado foi mantido fixo em todas as análises (157,78 mm para fêmeas e 162,71 mm para machos). Para os indivíduos mantidos em laboratório, os parâmetros e a longevidade obtidos foram k=0,001/dia; t o=-1,53; longevidade de 3117 dias (8,5 anos) para machos e k=0,002/dia; t o=-29,5; longevidade de 2795 dias para fêmeas (7,7 anos). Os parâmetros de crescimento e a longevidade estimados para os animais coletados em campo foram k=0,004/dia; t o=-4,23; 1267 dias (3,5 anos) para machos e k=0,004/dia; t o=-3,71; 1260 dias (3,45 anos) para fêmeas. Foram encontradas diferenças significativas entre animais de laboratório e de campo, sugerindo que a espécie responde de forma diferente ao ambiente em que está inserida.

The absence of hard structures which register age on crustaceans requires the use of length-based methods for age determination, and modal progression analysis (MPA) to estimate growth. In this paper, individual growth of the blue crab Callinectes sapidus Rathbun, 1896 was studied in the laboratory and in the field, and the growth curves estimated were compared. Crabs studied in the laboratory were obtained from field sampling and kept under controlled conditions (temperature = 25±2°C, and salinity = 20±5), on a water recirculating system. These animals were molt staged and measured (carapace width, taken from the last antherolateral spines in millimeters) before and after molting. Crabs used for field growth analysis were collected between 2002 and 2004 in predetermined sampling sites by using otter-trawl and renfro nets. Bertalanffy growth model was used to estimate the growth parameters of the crabs. Maximum carapace lengths were used as the estimative of the asymptotic length (157.78 mm for females and 162.71 mm for males). Growth parameters obtained from laboratory experiments were k=0.001/day; t o=-1.53; longevity= 3117 days for males and k=0.002/day; t o=-29.55; longevity= 2795 days for females. Growth parameters and longevity estimates for the field collected animals were k=0.004/day; t o=-4.23; 1267 days for males and k=0.004/day; t o=-3.71; 1260 days for females. Significant difference was observed among laboratory and field crabs, suggesting a different growth rate accordingly to the surrounding environment.

Utilizando o método de deslocamento modal para a identificação das idades, estimou-se o crescimento do siri-azul Callinectes sapidus Rathbun, 1896 em duas áreas de pesca no estuário da Lagoa dos Patos. Os indivíduos foram coletados entre fevereiro de 2005 e março de 2006 no Saco da Mangueira e Saco do Arraial por meio de arrasto de rede de portas da pesca artesanal. Coletou-se um total de 2.609 animais, sendo 1.193 machos e 1.416 fêmeas. Para obtenção das curvas de crescimento utilizou-se o modelo de von Bertalanffy. As curvas foram validadas pela sua adequação ao ciclo de vida e aspectos biológicos da espécie. O tamanho máximo de largura de carapaça (LCmáx) utilizado foi mantido fixo em todas as análises (LCmáx=162,71mm; ± d.p.=3,10 para machos e LCmáx=157,78mm; ± d.p.=5,45 para fêmeas), sendo esses valores médios das maiores medidas obtidas em mais de 20 anos de coletas no estuário. Os parâmetros de crescimento e longevidade foram estimados para machos (Saco da Mangueira, K=0,0039/dia; t o=-6.07; 1.195 dias; Saco do Arraial, K=0,0041/dia; t o=-5,84; 1.102 dias) e fêmeas (Saco da Mangueira, K=0,0040/dia; t o=-6,22; 1.153 dias; Saco do Arraial, K=0,0039/dia; t o=-5.91; 1.181 dias). As curvas de crescimento estimadas nesse trabalho denotam que a espécie atinge o tamanho mínimo de captura praticamente no primeiro ano de vida (120mm).

Using modal progression analysis for indirect age determination, growth of the blue crab Callinectes sapidus Rathbun, 1896 was estimated for two fishery areas of the Patos Lagoon. Individuals were sampled using a conventional gear of the artisanal fishery - trawl net - from February, 2005 to March, 2006 in 'Saco da Mangueira' and 'Saco do Arraial'. A total of 2,609 (1,194 males and 1,416 females) animals was caught. Growth curves were estimated using the von Bertalanffy growth model. Estimated growth curves were validated in the light of the life cycle and biological characteristics of the species. Asymptotic width (CWmax) was fixed in all analyses (162.71mm, ± s.d.=3.10 and 157.78mm, ± s.d.=5.45 for males and females respectively), as this value is an average of the maximum lengths of crabs caught in the estuary over a period of 20 years. Growth parameters and longevity were estimated for males ('Saco da Mangueira', K=0.0039/day; t o=-6.07; 1195 days; 'Saco do Arraial', K=0.0041/day; t o=-5,84; 1102 days) and females ('Saco da Mangueira', K=0.0040/day; t o=-6,22; 1153 days; 'Saco do Arraial', K=0.0039/day; t o=-5.91; 1181 days). Growth curves estimated in the present investigation indicate that the minimum legal size (120mm) is attained around the first year of life.

Na região estuarina da Lagoa dos Patos, o siri-azul Callinectes sapidus Rathbun, 1869 é o mais abundante dentre as espécies do gênero. Apesar do siri-azul exercer influência sobre as comunidades bentônicas, por ser considerado um predador do topo da cadeia alimentar, não existem muitos estudos sobre aspectos ecológicos, inclusive sobre a composição e variabilidade sazonal de sua dieta natural, neste estuário. O objetivo principal deste estudo foi investigar a composição da dieta do siri-azul, evidenciando possíveis relações com a comunidade bentônica da região estuarina da Lagoa dos Patos. O período de estudo foi de março de 2003 a março de 2004, com coletas bimestrais. Os organismos foram coletados com auxílio de rede de arrasto de fundo, com malha de 13 mm entre nós opostos. Ainda em campo os animais foram fixados em formol 10%. Após a coleta os animais foram separados quanto ao sexo, medidos (largura e comprimento da carapaça - cm) e pesados (peso - g). Após a triagem, os animais foram dissecados e os intestinos retirados e pesados. As análises dos conteúdos alimentares dos siris demonstraram que os hábitos alimentares são diversificados, constituindo-se principalmente de invertebrados bentônicos. O item encontrado com maior freqüência foi Detrito, seguido pelo molusco filtrador Erodona mactroides Bosc, 1802 (Erodonidae). Crustáceos da classe Ostracoda e grãos de areia foram importantes componentes dos conteúdos dos intestinos anteriores, sendo que areia não foi considerada como item alimentar, propriamente dito. Também foram encontradas cerdas e mandíbulas de poliquetos, além de sementes das macrófitas Ruppia maritima L. (Potamogatonaceae) e Zannichellia palustris L. (Potamogatonaceae). Este estudo serve como subsídio para medidas de proteção e conservação da população do siri-azul, bem como caracteriza relações tróficas com comunidades bentônicas do estuário da Lagoa dos Patos.

The Southern Brazil blue crab Callinectes sapidus Rathbun, 1869 is the most abundant crab of the genus Callinectes in Patos Lagoon estuary. Although this species is widely distributed throughout the Patos Lagoon estuary area, there is little information about its natural diet. This species is an important predator and has a significant influence on its prey populations. The aim of this study was to check the natural diet of blue crab through the foregut contents analysis. Crabs were collected using an otter trawl net from March 2003 to March 2004. After collected, crabs were preserved immediately in 10% formaldehyde. The carapace width, weight and sex were measured for each individual. The foregut of each crab was removed and stored in 70% ethanol. Blue crab feeds on a wide variety of sessile and slow moving invertebrates. The main item was Detritus, followed by the suspension-feeder mollusk Erodona mactroides Bosc, 1802 (Erodonidae). Sand grains and the small crustaceans of class Ostracoda, were an important component of the foregut contents, but sand grains were not considered food. Setae and pieces of Polychaeta and some seeds of submersed higher vegetation of Ruppia maritima L. (Potamogatonaceae) (beaked tasselweed), and Zannichellia palustris L. (Potamogatonaceae) (homed pondweed), were also found. This study has as purpose to provide information for a long-term protection and conservation of blue crab population and also to characterize its relationship with the macrobenthic communities in the Patos Lagoon estuary.

Kalliapseudes schubartii (Crustacea: Tanaidacea) é um invertebrado tubícola que habita fundos moles de regiões estuarinas e que distribui-se ao longo da costa sudeste e sul do Brasil e na costa uruguaia. Este tanaidaceo é comedor de depósitos e filtrador, e é presa de vários consumidores secundários. Taxas de mortalidade sazonal foram examinadas através de amostras feitas durante um ano num local da região estuarina da Lagoa dos Patos. Os resultados não demonstraram diferenças significativas entre as taxas de mortalidade nas diferentes estações do ano, o que sugere que populações de K. schubartii são fortemente predadas ao longo de todo o ano e que a premissa de maior mortalidade no verão/outono pode não ser correta em fundos de águas rasas não vegetados.

Studies were carried iut on seasonal mortality by taking samples of Kalliapseudes schubartii (Crustacea: Tanaidacea) for a year in the estuarine region of the Lagoa dos Patos (southern Brazil). Results demonstrated no significant difference in seasonal mortality rates, which suggest that populations of K. schubartii was heavily preyed on year round and that an assumption of a significantly higher mortality in summer/autumn than in spring/winter might not be held in unvegetated soft bottoms of the estuarine regions of the Lagoa dos Patos.

Com o objetivo de elucidar alguns aspectos da biologia reprodutiva de Ligia exotica Roux, 1828, duas populações que habitam o Estuário da Lagoa dos Patos (Molhe Oeste da Barra de Rio Grande e Ilha do Leonídeo) foram analisadas. A amostragem foi realizada quinzenalmente entre o verão/2003 e o inverno/2004. Os animais foram coletados manualmente durante uma hora. O período reprodutivo da espécie foi registrado para os meses de outubro a junho. Nenhuma fêmea ovígera foi observada de julho a setembro. No Molhe Oeste da Barra de Rio Grande, 5.376 indivíduos foram capturados (1.494 juvenis, 1.748 machos e 2.134 fêmeas, das quais 245 eram ovígeras). A proporção sexual estimada foi 0,78 (M:F). Para a análise da fecundidade, 178 fêmeas ovígeras com o marsúpio intacto foram analisadas. O comprimento total destas fêmeas variou entre 20,73 a 34,3 mm, e o número de ovos-embriões variaram de 33 a 142. O comprimento médio de primeira maturação sexual das fêmeas foi 24,65 mm e o número médio de ovos-embriões foi 88. Na Ilha do Leonídeo, 5.519 animais foram coletados (510 juvenis, 1.956 machos e 3.053 fêmeas, das quais 129 eram ovígeras). A proporção sexual foi 0,68 (M:F). Pequenas porcentagens de fêmeas ovígeras foram encontradas de setembro a maio, sendo a mais alta porcentagem observada no final de março. Neste local, 101 fêmeas ovígeras foram analisadas, com o comprimento total variando entre 17,62 a 28,61 mm e o número de ovos-embriões entre 25 e 113. O comprimento médio de primeira maturação sexual das fêmeas e o número médio de ovos-embriões foram, respectivamente, 21,43 mm e 73,8.

Aiming to elucidate some aspects of the reproductive biology of Ligia exotica Roux, 1828, two populations inhabiting the Estuary of the Patos Lagoon (West Breakwater of Rio Grande Channel and Leonidio Island) were analyzed. Sampling was performed fortnightly, from summer/2003 to winter/2004. Animals were collected manually during one hour. The reproductive season of the species occurred from October to June. No ovigerous females were observed from July to September. In West Breakwater of Rio Grande, 5,376 individuals were captured (1,494 juvenile, 1,748 males and 2,134 females, in which 245 were ovigerous). Sex ratio estimated was 0.78 (M:F). To perform fecundity analysis, 178 ovigerous females with intact marsupium were analyzed. Total length of these females varied from 20.73 to 34.3 mm, and the number of eggs-embryos ranged from 33 to 142. The mean length of sexual maturity of females was 24.65 mm and the mean number of eggs-embryos was 88.0. In Leonidio Island, 5,519 animals were collected (510 juvenile, 1,956 males and 3,053 females, from which 129 were ovigerous). The sex ratio was 0.68 (M:F). While the lowest percentages of ovigerous females were found from September to May, the highest percentage of ovigerous female was observed at the end of March. In this location, 101 ovigerous females were analyzed, with total length varying from 17.62 to 28.61 mm, and the number egg-embryos ranged from 25 to 113. The mean length of sexual maturity of females was 21.43 mm and the mean number of eggs-embryos was 73.8.

Metamysidopsis elongata atlantica (Bascescu, 1968) foi cultivada em laboratório em diferentes combinações de temperatura (13, 20, and 25°C) e salinidade (25, 30, and 35‰) para estimar o período de intermuda e a taxa de crescimento da carapaça. A temperatura afetou o período de intermuda e a taxa de crescimento dos animais. Misidiáceos criados a 13°C tiveram maiores períodos de intermuda que aqueles cultivados a 20 and 25°C. Enquanto animais criados a 13°C tiveram maior longevidade, fêmeas não desenvolvem marsúpio quando cultivadas nesta temperatura. A taxa de crescimento estimada para misidáceos entre 0 a 14 dias (idade no início da maturidade) foi 0,02 mm/dia, 0,04 mm/dia, e 0,05 mm/dia para animais cultivados respectivamente a 13°C, 20°C e 25°C.

Metamysidopsis elongata atlantica (Bascescu, 1968) was reared in the laboratory at different combinations of temperature (13, 20, and 25°C) and salinity (25, 30, and 35‰) to estimate the intermoult period and carapace growth rate. Temperature affected both intermoult period and growth rate of the animals. Mysids reared at 13°C had longer intermoult periods than those reared at 20 and 25°C. While animals reared at 13°C had the longest longevity, females did not develop marsupium when reared at this temperature. Growth rate estimated for mysids aged between 0 to 14 days (age at the onset of maturity) was 0.02 mm/day, 0.04 mm/day, and 0.05 mm/day for animals reared at 13°C, 20°C, and 25°C, respectively.

The stages of gonadal development for the female of "barba-ruça" shrimp (Artemesia longinaris Bate, 1888) were characterized based on histological analysis. Four stages (immature, almost mature, ripe and spawned) were determined according to the structure and arrangement of cells in the ovary. Each stage corresponds macroscopically to a characteristic color, except stages I (immature) and IV (spawned), in which colors are very similar and can be distinguished only microscopically. The chromatic scale varies from white/translucent (stage I), neutral green (almost mature) to dark green (ripe). The mean size of cells was 56.9 µm (±3.5) (stage I), 127 µm (±2.6) (stage II) and 183 µm (±1.91) (stage III). The size frequency of cells was polimodal, and different cell stages were observed in ripe ovary, suggesting the occurrence of multiple spawning. The chromatic scale developed is an important tool for laboratory analysis, and can be easily used to identify the gonadal stages.

While all species of the genus Callinectes Stimpson, 1860 have a continuous distribution on the Atlantic coast of the Americas, Callinectes sapidus Rathbun, 1896 is the only one with disjunct distribution. Considering that this species was introduced in Europe and Japan, it has been suggested that the occurrence of C. sapidus on the southern coast of Brazil was due to the transport by ballast water. In the archaeological site Ariano Souza, located in the estuary of the Patos Lagoon (southern Brazil), remains of crustaceans, including claws of approximately two thousand years ago, were found. A preliminary analysis of this material showed Callinectes chelae. Because this archaeological site is located inside the estuary, it has been hypothesized that these chelae belong either to C. sapidus or to C. danae Smith, 1869. A comparison between pincers collected in the archaeological and pincers of these two species (90 dactyls, 30 of each type) was performed. The analysis (ANOVA) considered the variability of seven characters of the dactyls, and demonstrated the existence of two groups. Results showed that the measured characters suffice to separate these species, and indicated that the material found in the archaeological site belongs to C. sapidus. The hypothesis of the introduction of C. sapidus in the area is rejected. The possible biogeographic history of the species is discussed.

Twelve species of Pinnotheridae from Santa Catarina and Rio Grande do Sul States, Brazil, are redeseribed and illustrated; a key of identification is presented. Clypeasterophilus stebbingi Rathbun, 1918; Pinnotheres garthi Fenucci, 1975 and Pinnixa brevipollex Rathbun, 1898 are reported for the first time for Brazil. Clypeaslerophilus stebbingi Rathbun, 1918 and Tumidotheres maculatus Say, 1818, are new record for Santa Catarina. Fabia insularis Melo, I971 and Pinnotheres emiliai Melo, 1971 are revalitaded; Fabia sebastianensis Rodrigues da Costa, 1969; Pinnotheres garthi Fenucci, 1975; Pinnotheres emiliai Melo, 1971 and Pinnixa patagoniensis Rathbun, 1918 are new records for Rio Grande do Sul. Pinnixa brevipollex Rathbun, 1898 is a new record for Santa Catarina and Rio Grande do Sul.