Composição e distribuição dos Crustacea (Decapoda) na Lagoa do Peixe, Rio Grande do Sul, Brasil.

The Lagoa do Peixe ("Peixe's Lagoon") is located between Atlantic Ocean and Lagoa dos Patos and is 30 Km long and 0,5-2,0 Km wide (31 °13 ' S, 50055'W -3 10 26'S, 51009' ). For one year, the composition and distribution of Crustacea Decapoda were analyzed monthly (fTOm Julyl1 994 to June/1995), in seven subareas (terrestrial border and aquatic areal and physical and chemical parameters (depth, salinity, sediment texture, oxygen in water, organic material of sediment and water temperature) were registered. Decapoda fTOm the families Grapsidae, Ocypodidae, Portunidae (Brachyura), Diogenidae (Anomura) and Penaeidae (Penaeidea) were captured. Chasmagnathus granulata Dana 1851 was found ali months near the canal connecting A tlantic Ocean and Lagoa do Peixe, but inside the lagoon it was collected only in October/94 and June/95, and in extreme subareas it was sampled in February/95 when the salinity was 31 %0 at these sites. Callinectes sapidus Rathbun, 1896 and Cyrtograpsus angulatus Dana, 1851 were captured throughout the year, except October/94 and April/95, respectively. Both species were found in ali areas of sample, indicating a high plasticity in relation to the factors analyzed in this study. Another species captured probably come in the lagoon in specific months, when the environrnent provides ideal conditions for their developments

Comparação da dieta natural do siri-azul Callinectes sapidus Rathbun,1896 (Crustacea: Decapoda: Portunidae) em dois locais no estuário da Lagoa dos Patos, RS, Brasil

O siri-azul Callinectes sapidus Rathbun, 1896 é o mais abundante dentre as espécies do gênero na região estuarina da Lagoa dos Patos, sendo considerado um predador bentônico chave. O presente estudo tem por objetivo fazer a comparação da dieta natural do siri-azul entre dois locais do estuário da Lagoa dos Patos. As coletas foram realizadas em fevereiro e maio de 2009 com rede de arrasto de portas durante 15 minutos. No laboratório, os intestinos foram pesados e o grau de repleção avaliado. A contribuição de cada item alimentar foi analisada com a freqüência de ocorrência e a freqüência relativa dos pontos. Para comparação entre os dois pontos de coleta foi realizado teste G com fator de correção de Williams (p<0,05). Nas Bandeirinhas foi possível identificar 18 itens, os mais ocorrentes foram resto vegetal, Erodona mactroides, Heleobia australis e Brachyura; no Saco da Mangueira foi possível identificar 12 itens, entre os mais ocorrentes estão resto vegetal, Erodona mactroides e camarão. Foi observada diferença entre os itens ocorrentes na dieta de acordo com o local de coleta. O siri-azul se caracteriza por ser generalista oportunista, diferindo sua alimentação de acordo com a disponibilidade de presas do ambiente.The blue crab Callinectes sapidus Rathbun, 1896 is the most abundant species of genus in the estuarine region of Patos Lagoon, considered as key benthic predator. This study aims to compare the natural diet of the blue crab between two sites in the estuary of Patos Lagoon. Samples were collected in February and May 2009 by using an otter trawl towed during 15 minutes. In the laboratory, the intestines were weighed and assessed the degree of fullness. The contribution of each food item was analyzed by using the frequency of occurrence and relative frequency of points. The comparison between both sites was performed using G test with Williams correction factor (p <0.05). At Bandeirinhas were identified in 18 items, the rest were more occurring plant Erodona mactroides, Heleobia australis and Brachyura. At Saco da Mangueira 12 items were identified, among the rest are occurring plant Erodona mactroides and shrimp. Difference was found among the items occurring in the diet according to the collection site. The blue crab is characterized by opportunistic generalist, its diet differs according to prey availability in the environment

Crescimento de Chasmagnathus granulatus (Crustacea, Decapoda, Varunidae) na Lagoa do Peixe, Rio Grande do Sul, Brasil

O estudo do crescimento em largura da carapaça de Chasmagnathus granulatus Dana, 1851 foi baseado em dados de 1940 exemplares coletados na Lagoa do Peixe, Estado do Rio Grande do Sul, Brasil. As coletas foram realizadas de julho/1994 a junho/1995. Os caranguejos foram coletados manualmente nas margens da lagoa e em laboratório foram separados por sexo e a largura da carapaça mensurada. O modelo de von Bertalanffy foi utilizado para a descrição do crescimento. As curvas de crescimento em largura (mm), para dados obtidos através da progressão modal, são descritas pelas equações: Lt= 44,69 [1- e -0.0066(t+20,45)] e Lt= 37,63 [1- e -0.0072(t+21,92)], resultando em idades máximas estimadas de 2 anos para ambos os sexos.<br>The growth study in width of Chasmagnathus granulatus Dana, 1851 was based on biometric data of 1,940 specimens colleted at Lagoa do Peixe, state of Rio Grande do Sul, Brazil. The samplings were realized from July/1994 to June/1995. For each captured specimens the sex and width of cephalothorax were recorded. The von Bertalanffy's model was utilized for the growth description. The growth curves in width (mm), for data obtained through the modal progression, are described by the equations: Lt= 44,69 [1- e -0.0066(t+20,45)] and Lt= 37,63 [1- e -0.0072(t+21,92)], resulting in a maximum estimated age of 2 years for males and females

Natural diet of neohelice granulata (Dana, 1851) (Crustacea, Varunidae) in two salt marshes of the estuarine region of the Lagoa dos Patos Lagoon

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

Composition and distribution ofCrustacea (Decapoda) from Lagoa do Peixe, Rio Grande do Sul, Brazil.

Submitted by Trilce Morales ([email protected]) on 2011-06-15T23:45:29Z No. of bitstreams: 1 Composição e distribuição dos Crustacea (Decapoda) na Lagoa do Peixe, Rio Grande do Sul, Brasil..pdf: 3588733 bytes, checksum: 690b109ac21fa71dd41e3eebd6818609 (MD5)Approved for entry into archive by Barbara Milbrath([email protected]) on 2011-06-17T04:08:36Z (GMT) No. of bitstreams: 1 Composição e distribuição dos Crustacea (Decapoda) na Lagoa do Peixe, Rio Grande do Sul, Brasil..pdf: 3588733 bytes, checksum: 690b109ac21fa71dd41e3eebd6818609 (MD5)Made available in DSpace on 2011-06-17T04:08:36Z (GMT). No. of bitstreams: 1 Composição e distribuição dos Crustacea (Decapoda) na Lagoa do Peixe, Rio Grande do Sul, Brasil..pdf: 3588733 bytes, checksum: 690b109ac21fa71dd41e3eebd6818609 (MD5) Previous issue date: 2000The Lagoa do Peixe ("Peixe's Lagoon") is located between Atlantic Ocean and Lagoa dos Patos and is 30 Km long and 0,5-2,0 Km wide (31 °13 ' S, 50055'W -3 10 26'S, 51009' ). For one year, the composition and distribution of Crustacea Decapoda were analyzed monthly (fTOm Julyl1 994 to June/1995), in seven subareas (terrestrial border and aquatic areal and physical and chemical parameters (depth, salinity, sediment texture, oxygen in water, organic material of sediment and water temperature) were registered. Decapoda fTOm the families Grapsidae, Ocypodidae, Portunidae (Brachyura), Diogenidae (Anomura) and Penaeidae (Penaeidea) were captured. Chasmagnathus granulata Dana 1851 was found ali months near the canal connecting A tlantic Ocean and Lagoa do Peixe, but inside the lagoon it was collected only in October/94 and June/95, and in extreme subareas it was sampled in February/95 when the salinity was 31 %0 at these sites. Callinectes sapidus Rathbun, 1896 and Cyrtograpsus angulatus Dana, 1851 were captured throughout the year, except October/94 and April/95, respectively. Both species were found in ali areas of sample, indicating a high plasticity in relation to the factors analyzed in this study. Another species captured probably come in the lagoon in specific months, when the environrnent provides ideal conditions for their developments