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1998-01-01
Resumo em português A estrutura das associações zooplanctônicas do complexo estuarino de Paranaguá foi estudada no inverno de 1993 e no verão de 1994. Copépodes dos gêneros Acartia, Paracalanus, Parvocalanus, Temora, Pseudodiaptomus, Oithona e Euterpina foram dominantes, atingindo até cerca de 90% da densidade total. A única espécie que ocorreu preferencialmente em salinidades inferiores a 15 foi o calanóide Pseudodiaptomus richardi, que representa o principal componente do holopl (mais) ncton nos setores oligohalinos. Acartia tonsa e Oithona oswaldocruzi predominaram nos trechos intermediários, associadas a outras espécies estuarino-marinhas que suportam maiores variações de salinidade, como Acartia lilljeborgi, Pseudodiaptomus acutus e Oithona hebes. Espécies marinho-eurihalinas como Temora turbinata, Paraca/anus quasimodo, Oithona simplex e Euterpina acutifrons ocorreram em salinidades tão baixas quanto 15, mas foram mais abundantes na área externa influenciada pela água costeira. Várias espécies marinho-estenohalinas, associadas principalmente às águas quentes da Corrente do Brasil, foram registradas no setor euhalino. Outros grupos zooplanctônicos numericamente importantes foram os tintinineos, apendiculárias, cladóceros e alguns representantes do meroplncton, como as larvas de poliquetas e decápodes. Os máximos de abundncia do zooplncton (até cerca de 82000 org.m-3) ocorreram nos setores intermediários, em salinidades variando entre 15 e 30, coincidindo aproximadamente com o padrão de distribuição da biomassa fitoplanctônica. Resumo em inglês Zooplankton community structure was investigated in the estuarine complex of Paranaguá (Southern Brazil) during July 1993 (winter) and February-March 1994 (summer). Copepods belonging to the genera Acartia, Paracalanus, Parvocalanus, Pseudodiaptomus, Temora, Oithona and Euterpina dominated the zooplankton associations, attaining up to 90% of total densities. Pseudodiaptomus richardi was the dominant estuarine copepod in oligohaline stretches with salinities below 15. Est (mais) uarine marine species such as Acartia tonsa, Oithona hebes and Oithona oswaldocruzi reached high densities in salinities ranging from 17 to 25. Other abundant estuarine marine species including Acartia lilljeborgi and Pseudodiaptomus acutus occurred in a broader salinity range. Marine euryhaline copepods were found in salinities as low as 15, but were usually more abundant in areas under the influence of coastal waters. Several marine stenohaline species associated with the warm waters of the Brazil Current were recorded in the euhaline areas. Other important zooplanktonic groups in this estuarine complex were tintinnids, appendicularians, cladocerans and meroplanktonic larvae of polychaetes and decapods. Density maxima (up to 82400 org.m-³) were found in the intermediate stretches - in salinities varying from 15 to 30 - corresponding approximately to the distributional pattern of phytoplankton biomass.
2000-09-01
Resumo em inglês Ultrastructure of spermatozoa of the crab Ucides cordatus Linnaeus, 1763 is described and illustrated. Three parts can be distinguished: 1. the elongate-ovoid acrosome located anteriorly; 2. the cytoplasmic region; and 3. the nuclear region. The acrosome is composed of a thick electron-dense wall and a less electron-dense subacrosomal space. The cytoplasm region connects the acrosome with the nucleus, and three arms filled with microtubules arise from this region. The nuc (mais) leus is polymorphous. The spermatozoon of Ucides cordatus follows the general pattern described for other Decapods.
2006-12-01
Resumo em português O desenvolvimento das gônadas de uma espécie pode ser avaliado pela determinação do índice gonadossomático e hepatossomático. O hepatopâncreas é o maior centro de reservas em decápodos e essas reservas podem ser transferidas para as gônadas durante o seu desenvolvimento. O objetivo desta pesquisa foi avaliar, no lagostim Parastacus varicosus Faxon, 1898, o desenvolvimento das gônadas, por meio de observações macro e microscópicas, além de determinar a vari (mais) ação dos índices gonadossomático e hepatossomático. Os lagostins foram amostrados na bacia hidrográfica do rio Gravataí, localidade Cova do Touro, Estado do Rio Grande do Sul. As gônadas das fêmeas foram pesadas para a determinação do índice gonadossomático e para análise histológica. O peso do hepatopâncreas também foi obtido para a determinação do índice hepatossomático. Os resultados mostraram uma diminuição do índice hepatossomático e um aumento do índice gonadossomático das fêmeas, no período de passagem da primavera para o verão, o que sugere uma possível transferência das reservas do hepatopâncreas para a gônada no período reprodutivo. No entanto, considerando que essa diminuição não foi significativa ao nível de 0,05, sugere-se que outros tecidos e/ou a hemolinfa possam estar contribuindo com a transferência de suas reservas. Resumo em inglês The level of gonadal development of a species can be evaluated by the determination of the gonadossomatic (GSI) and the hepatossomatic (HSP) indices. The hepatopancreas is the most important centre for storage of reserves in decapods, which can be transferred to the gonads during their development. The aim of this study was to estimate gonadal development of Parastacus varicosus Faxon, 1898 by means of macro and microscopic observations, as well by the inspection of the v (mais) ariations of gonadossomatic and hepatossomatic indices. The crayfishes were collected in the Gravataí hydrographic basin, Cova do Touro locality, State of Rio Grande do Sul, Brazil. Female's gonads were weighted for the recognition of the gonadossomatic index and histological analysis. Hepatopancreas weight was also obtained to determine the hepatossomatic index. The results showed a decrease of the hepatossomatic index and an increase of the gonadossomatic index in females during the seasonal transition period from spring to summer, suggesting a possible transfer of the hepatopancreatic reserves to the gonads during the reproductive period. However, considering that this decrease did not show significance at p>0.05 level, it is likely that other tissues contribute for this transfer, as hemolymph, for instance.
1995-01-01
Resumo em inglês The occurence of Decapoda crustaceans in the diet of Dasyatis guttata (Bloch & Schneider, 1801) (Elasmobranchii. Dasyatididae) is reported. Inferences are also made about some aspects of the predator - prey relationship in the area around the Ecological Station.
2002-07-01
Resumo em inglês A study about species composition, relative abundance, densities, size composition, reproductive and recruiting periods, sex proportion and species diversity of the decapod populations associated to worm reefs of P. caudata (Kröyer, 1856) was carried out. Monthly, samples of worm reef were obtained from August/1997 to July/1998 from Caiobá Beach, Matinhos (25º51 'S and 48º32'W), Paraná State, southern Brazil. Air temperature oscillated from 14.5ºC (July) to 31.0ºC (mais) (February), surface water from 18.0ºC (July) to 28.0ºC (January and February), and the salinity from 22%0 (February) to 34%0 (September). Eigth decapod species were found: Petrolisthes armatus (Gibbes, 1850); Pachygrapsus transversus (Gibbes, 1850); Panopeus americanus Saussure, 1857; Eurypanopeus abbreviatus (Stimpson, 1860); Menippe nodifrons Stimpson, 1859; Pilumnus dasypodus Kingsley, 1879; Eriphia gonagra (Fabricius, 1781); and Alpheus heterochaelis Say, 1818. The total density varied from 1.66 ind./l (September) to 33.93 ind./l (January). Petrolisthes armatus was the most numerous species. Six species were constant, one was accessory, and another accidental. Shannon-Wiener diversity index was the lowest when compared with other similar habitats. Ovigerous females occurred in six species, but no species showed continuous breeding all year round. The majority of the associated decapods were smaller than those reported in the literature.
1998-01-01
Resumo em inglês Decapod crustaceans from rocky shore at Farol Isle, Matinhos, Paraná, Brazil. II. Spatial distribution of population densities. A study of the spatial distribution of the decapod populations from a rocky shore at Farol Isle, Matinhos, State of Paraná, Brazil (25º51'S, 48º32'W) was canied out. In the supralittoral the rocky surface is covered partially by a layer of litter coming from the terrestrial habitats; in the midlittoral boulders and pebbles cover the rocky bas (mais) in and in the infralittoral, there is a belt of seaweeds. A total of 8 samples were taken by hand, two from each of the following levels: supralittoral (emersion time 8-12 hours), upper midlittoral (4-8), lower midlittoral (0-4) and limit between midlittoral and infralittoral, monthly, from May/1990 to April/1991. The number of species increased from supralittoral (5) to infralittoral (22) and a clear vertical zonation on density was observed according to the emersion time gradient. The supralittoral is characterized by grapsids Armases angustipes (Dana, (1852), Cyclograpsus integer H. Milne Edwards, 1837 and Metasesarma rubripes (Rathbun, 1897) which have terrestrial habits and aerial respiration as a main way in obtaining the oxygen. In the midlittoral, the decapods show three basic types of adaptation against emersion desiccation and thermal stresses: (1) by digging into wet mud among the stones such as Panopeus americanus Saussure, 1857, Panopeus occidentalis Saussure, 1857 and Eurypanopeus abbreviatus Stimpson, 1860, (2) by resting in shady and wet space between the boulders and pebbles or underside of them, like Pachygrapsus transversus (Gibbes, 1850), Petrolisthes armatus (Gibbes, 1850) and adults of Menippe nodifrons Stimpson, 1859 and (3) by clinging over the soaked filamentous algae layer on the pebbles or bouders surfaces, a strategy observed in small species such as Pilumnus dasypodus Kingsley, 1879, Podochela sp., Petrolisthes galathinus (Bosc, 1801 ), Alpheus bouvieri A. Milne Edwards, 1878 and juveniles of Menippe nodifrons. In the infralittoral, small species which are vulnerable to desiccation stresses share space by diversification of their diet and adaptation strategies such as camouflage, body color change according to the substratum, flattened body for tight adhesion on hard surface and rapid movements. The main species of this zone are Petrolisthes armatus, Petrolisthes galathinus, juveniles of Menippe nodifrons, Epialtus brasiliensis Dana, 1852, P. dasypodus, Synalpheus fritzmuelleri Coutière, 1909, Megalobrachium roseum (Rathbun, 1900) and species of Palaemonidae. The rocky shore at Farol Isle is a complex architectural environment due to the conjunction of diversified habitats such as litter over a hard surface, spaces and crevices among boulders and pebbles, muddy substratum and phytal.
1996-01-01
Resumo em inglês Seasonal variation of the food items of the "bagre-urutu", Genidens genidens is analysed based on monthly samples between September, 1993 and April, 1995 at the Guaratuba Bay, coast of Paraná. The stomach contents of 105 fish is analysed by the Occurrence Frequency Method and 41 of these have also been analysed by the Volumetric Method. Matching both methods using the Preponderance índices, a larger incidence of decapods is determined, followed by other crustaceans, mol (mais) luscs, polychaets, fish, and plant material. The data show the existence of a strong seasonal variation in the diet.
1998-01-01
Resumo em inglês Seasonal variation of food items of Bairdiella ronchus (Cuvier, 1830) classified by size was analysed based on monthly samples between september/1993 and september/1996 at the Guaratuba Bay, Southern Brazil. The stomach contents of a hundred eighty-two fishes were analysed by the Occunence Frequency Method and Point Count for a Lot Method. The individuais were divided in two groups, smaller and longer than 140mm, and a comparative study of digestive tract and branchial ar (mais) e was performed for these groups. For fishes smaller than 140mm the following sequence of items was obtained matching both methods by using the Preponderance índices: decapods (subdivided in Brachyura, Caridea and Penaeidea), polychaets, isopods, fishes, unidentified material, copepods, amphipods, molluscs and plant material. For fishes longer than or equal to 140mm the sequence was decapods, polychaets, fishes, copepods, amphipods, isopods, molluscs and plant material, in this order. These results suggest that Bairdiella ronchus at the Guaratuba Bay is a carnivorous species using mainly decapod crustaceans as food throughout the year.
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