ABSTRACT
ABSTRACT The aim of this study was to describe the behavior of newly-hatched juveniles and maternal care in Aegla schmitti. The experiment was conducted using seven ovigerous females with eggs at different stages of embryonic development and 12 eggs that had been placed in a separate aquarium. We observed asynchronous hatching in all females, with a mean of 66 hatched juveniles per female. The females also exhibited extended maternal care, allowing the juveniles to remain inside their abdominal chamber or on other parts of their body in the first few days after hatching. The juveniles that hatched in a separate aquarium fed on the remaining eggs, despite food being available. The incubation period and number of hatched eggs are highly variable between species with direct development, with no clear pattern being evident. However, asynchrony in hatching time is apparently common among freshwater anomurans, most likely due to the environmental conditions in which they live. Parental care is an important trait for crustaceans that live in osmotically unfavorable environments, such as freshwater, increasing the survival rate of juveniles.
ABSTRACT
The opportunistic predation on the fishes Astyanax fasciatus and Crenicichla sp. entangled in gill net by the aeglid crabs Aegla grisella and Aegla singularis was observed in rivers of southern Brazil. These events occurred in two rivers located at the National Forest of Passo Fundo, in Mato Castelhano municipality, Rio Grande do Sul State and Tangará municipality, Santa Catarina State. In both places the fish showed similar wound pattern, with eyes and fins being consumed first. However, predation of the whole body was also recorded, probably due to the high number of aeglid crabs feeding on the same individual. This record intended to contribute for understanding the natural diet of these crabs in freshwater environments.
A predação oportunista dos peixes Astyanax fasciatus e Crenicichla sp. emalhados em rede de espera pelos eglídeos Aegla grisella e Aegla singularis foi observada em rios do Sul do Brasil. Estes eventos ocorreram em dois rios na Floresta Nacional de Passo Fundo, município de Mato Castelhano, RS e no município de Tanguará, SC. Em ambos os locais os peixes apresentavam um padrão de mutilação semelhante, com olhos e nadadeiras sendo consumidos primeiramente. No entanto, a predação de todo o corpo também foi registrada, provavelmente em decorrência do elevado número de eglídeos se alimentando de um mesmo indivíduo. Esse registro visa contribuir para o entendimento da dieta natural dos eglídeos em ambientes de águas continentais.
ABSTRACT
Este estudo teve por objetivo descrever a assembleia de crustáceos decápodos associados às cordas de cultivo de mexilhões em uma fazenda marinha localizada na Enseada da Armação do Itapocoroy, no Município de Penha, Santa Catarina, sul do Brasil. Os seguintes aspectos foram tratados: composição de espécies e peso total, sucessão de espécies e oscilação temporal da abundância, riqueza de espécies e diversidade (Shannon). O crescimento do mexilhão em (altura da concha e peso dos indivíduos) também, foram apresentados. Os decápodos foram amostrados de 15 cordas amostradas bimensalmente (três cordas a cada dois meses). Um total de 501 decápodos foram capturados, pertencentes a nove famílias, 15 gêneros e 21 espécies. A família dominante foi Porcellanidae, com sete espécies, seguida de Panopeidae (cinco) e de Pilumnidae (três), enquanto as demais foram representadas por uma espécie. A espécie mais abundante foi Pilumnus dasypodus (n = 244) que, junto com Synalpheus fritzmuelleri, Pachycheles laevidactylus, Pisidia brasiliensis, Menippe nodifrons, Pachycheles monilifer e Petrolisthes galathinus, somou 88% das ocorrências. A riqueza de espécies aumentou de três para 15 durante o experimento e a diversidade de espécies mostrou seu máximo no quinto mês seguido pelo nono, devido ao aumento da disponibilidade de refúgios no interior do substrato biológico composto por mexilhões vivos. O peso total dos decápodos representou apenas 3% do peso total das cordas de cultivo, devido ao seu tamanho reduzido. Isto indica que estes animais não podem ser considerados prejudiciais para o cultivou mexilhões. As cordas desempenham o papel de fornecer abrigo e fonte de alimento, já que a maioria destes decápodos passa todo o período bentônico do seu ciclo de vida neste biótopo.
This study aimed to describe the assemblage of decapod crustaceans associated with the mussel farming ropes located in the Armação do Itapocoroy Bay, in the municipality of Penha, Santa Catarina State, southern Brazil. The following aspects were assessed: species composition and total weight, succession of species and temporal oscillation of abundance, species richness and Shannon's diversity. The growth data (height and weight of the shells) of the biological substrate (mussels) are also presented. During the nine months of the experiment, associated decapods were collected from 15 ropes (three ropes every other month). A total of 501 decapods were collected that belonged to nine families, 15 genera and 21 species. The most dominant family was Porcellanidae, with seven species, followed by Panopeidae (five) and Pilumnidae (three), while the remaining families were represented by one species each. The most abundant species was Pilumnus dasypodus (n = 244) that together with Synalpheus fritzmuelleri, Pachycheles laevidactylus, Pisidia brasiliensis, Menippe nodifrons, Pachycheles monilifer and Petrolisthes galathinus summed up 88% of decapod. Species richness increased from three to 15 during the experiment and species diversity showed its maximum in the fifth and ninth month, due to increased availability of shelters within biological substrate composed of living mussels. The total weight of decapods represented only 3% of the total weight of the farming ropes, due to the smallness of them. This indicates that these animals cannot be considered harmful for the mussel farming. The ropes play a role of shelter and as food resource, since most of these decapods spend all their bentic life in this biotope.
ABSTRACT
Uma chave pictórica de identificação foi elaborada para as espécies de caranguejos das famílias Eriphiidae, Menippidae, Panopeidae e Pilumnidae ocorrentes em águas rasas do litoral do Estado do Paraná. Uma descrição das características de reconhecimento e figuras das espécies também são apresentadas. Exemplares vivos foram obtidos de manguezal, estuário e cultivo de ostras na Baía de Guaratuba e costão rochoso de Matinhos. Os desenhos e a análise foram baseados nos exemplares coletados recentemente e naqueles depositados no Museu de História Natural do Capão da Imbuia e no Laboratório de Ecologia de Crustacea UFPR. Um total de 13 espécies foi analisado, das quais nove de Panopeidae, duas de Pilumnidae e uma de Eriphiidae e Menippidae. Esta riqueza de espécies foi considerada similar à das áreas vizinhas, apesar da curta extensão do litoral do Estado do Paraná.
A pictorial species identification key for crabs of the families Eriphiidae, Menippidae, Panopeidae and Pilumnidae from shallow waters of Paraná State coast was elaborated. A description of the recognition characteristics and illustrations of the species are also presented. Crab samples were obtained from mangrove, estuary and oyster farming located in Guaratuba Bay and rocky shore in Matinhos city. Drawings and analyses were based on freshly collected specimens and on those deposited at Natural History Museum of Capão da Imbuia and at Laboratory of Ecology of Crustacea UFPR. A total of 13 species were analyzed, from which nine species of Panopeidae, two Pilumnidae and one of Eriphiidae and Menippidae. This species richness was considered similar to neighboring areas in spite of the short extension of the Paraná State coast.
ABSTRACT
Uma chave de identificação foi elaborada para as espécies de caprelídeos registradas no litoral dos estados do Paraná e de Santa Catarina. Os exemplares examinados fazem parte do acervo de coleções científicas ou são provenientes de coletas realizadas nestes estados. Nove espécies pertencentes à família Caprellidae, das quais oito Caprellinae - Caprella danilevskii, Caprella dilatata, Caprella equilibra, Caprella penantis, Caprella scaura, Mayerella sp., Paracaprella pusilla e Pseudaeginella montoucheti - e uma Phtisicinae - Phtisica marina - foram tratadas no presente estudo.
An identification key was produced for caprellid species recorded from the coast of Paraná and Santa Catarina states, Southern Brazil. Analyzed specimens are part of scientific collections or were obtained from nature, within these states. Nine caprellid belonging to the family Caprellidae, from which eight of Caprellinae - Caprella danilevskii, Caprella dilatata, Caprella equilibra, Caprella penantis, Caprella scaura, Mayerella sp., Paracaprella pusilla e Pseudaeginella montoucheti - and one Phtisicinae - Phtisica marina - were treated in the present study.
ABSTRACT
A characterization of the occupied shells by the hermit crab Clibanarius vittatus was carried out. Hermit crabs were collected in the intertidal zone, during the low spring tide monthly from April 2005 to March 2006. They were sexed and their cephalothoracic shield length (CL) was measured. Shells were identified, dried, weighed and the aperture length (AL) and width (AW) were measured. 1187 crabs were collected (949 males, 216 females and 22 intersexes), which occupied 12 species of gastropod shells. Stramonita haemastoma, Olivancillaria urceus and Dorsanum moniliferum made up 96.55 percent of the total shell species. Male hermit crabs attained significantly larger sizes than females; therefore, males occupied a wider spectrum of shells in size and weight. A stronger correlation ratio was obtained between CL and AW of S. haemastoma. Last whorl with a rounded shape and a spacious inner area is a common feature of all shell species most frequently occupied by this hermit crab where it occurs. The successful establishment of C. vittatus at Baixio Mirim is mainly due to the appropriately shaped and wide range of size of S. haemastoma shells that were most often occupied by the hermit crabs of the studied population.
A caracterização das conchas ocupadas pelo ermitão Clibanarius vittatus (Bosc, 1802) foi realizada. Os ermitões foram coletados de abril/2005 a março/2006, na zona intertidal, durante a maré baixa de sizígia. Os ermitões tiveram o sexo reconhecido e foram medidos no comprimento do escudo ce-falotorácico. As conchas foram identificadas, pesadas depois de secas e edidas no copriento e na largura da abertura. Foram coletados 1187 ermitões (949 machos, 216 fêmeas e 22 intersexos) que ocuparam 12 espécies de conchas de gastrópodes. Stramonita haemastoma, Olivancillaria urceus e Dorsanum moniliferum perfizeram 96,55 por cento do total das conchas ocupadas. Ermitões machos atingiram tamanhos significativamente maiores do que as fêmeas; entretanto ocuparam um maior espectro de conchas em tamanho e peso. Fortes índices de correlação foram obtidos para a relação entre o escudo cefalotorácico dos ermitões e a largura da abertura de S. haemastoma. A última espira espaçosa e de formato globoso é um aspecto comum das conchas mais frequentemente ocupadas pelo presente ermitão em todos os locais de sua ocorrência. O sucesso no estabelecimento de C. vittaus no Baixio Mirim é devido principalmente ao formato e à amplitude de tamanhos das conchas de S. haemastoma, as quais são mais frequentemente ocupadas pelos ermitões da população estudada.
Subject(s)
Animals , Female , Male , Anomura/physiology , Anomura/anatomy & histology , Brazil , Seasons , ShellfishABSTRACT
The Perequê and Penedo rivers flow through the plains of Praia de Leste and fall into the sea between the municipalities of Pontal do Sul and Ponta do Poço. Both of these rivers belong to the sub-basin of Paranaguá Bay, and are constituent parts of the hydrographic basin of the Atlantic Ocean (State of Paraná). Four sites along the Perequê River (Stations 1-4) and one along the Penedo River(Station 5) were monitorated for water pollution over a 12 month period. During the period of December 1995 to November 1996, three water samples were collected from each site, placed in sterilized bottles and transported to the laboratory in ice-boxes. They were analyzed for the occurrence of total and decal coliforms, temperature and pH. Fecal pollution was detected throughout the period of study. Coliform contamination was smaller in Station 1 and 5 than in any other sites, probably due to lesser influence from urbanized areas. Water as Station 4 was strongly contaminated due to its close proximity to a sewage canal. This study demonstrated that the Pequerê and Penedo rivers, freshwater shrimps habitats, were heavily contaminated with fecal indicator bacteria, and this occurrence was not related with temperature or pH(au)