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Revista Brasileira de Zoologia

versión impresa ISSN 0101-8175

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MASUNARI, Setuko; OLIVEIRA, Edinalva  y  KOWALCZUK, Vânia Graciele Lezan. Decapod crustaceans from rocky shore at Farol Island, Matinhos, Paraná, Brazil. I: temporal distribution of population densities. Rev. Bras. Zool. [online]. 1998, vol.15, n.1, pp. 219-239. ISSN 0101-8175.  http://dx.doi.org/10.1590/S0101-81751998000100020.

A study of the temporal distribution of the decapod populations from a rocky shore at Farol Isle, Matinhos, State of Paraná, Brazil (25o51'S e48o32'W) was carried out. The rocky shore is 13m wide when the tidal level is zero meter and about 8o inclination. In the supralittoral, the rocky basins is mostly covered by a layer of litter coming from the terrestrial environment. In the midlittoral and upper infralittoral, the rocky slope is overlayed by boulders and pebbles and they constitute a highly complex environment of crevices, holes and concavities; the underlayer pebbles are embedded in sand, gravel and mud. In the infralittoral fringe, macrocospic algae grow as a continuous belt. Eight samples were taken by hand, monthly, from May-90 to April-91: two from supralittoral, four from midlittoral and two from infralittoral fringe. The density was calculated as number of individuais per cubic meter of pebble piles. The air temperature oscillated from 13.0oC (May-90) to 27.0oC (March-91), the surface water temperature from 16.0oC (July-90) to 28.0oC (February-91) and salinity from 6.7‰ (November-90) to 29.4‰ (July-90). There were registered 27 species (14 brachyuran crabs, 5 anomuran crabs and 8 caridean). The total density of decapod varied from 309.28 ind.m-3 (June-90) to 1,483.22 ind.m-3 (July-90). The density oscillated according to the temperature or salinity fluctuation only in three species. High densities were correlated to the breeding months in four species. Petrolisthes armatus (Gibbes, 1850) was the most numerous species and its density oscillated from 111.76 ind.m-3 (August-90) to 668.25 ind.m-3 (March-91). Eleven species occurred constantly (at least in 8 months), among which, five had a continuous breeding all year round: Synalpheus fritzmuelleri Coutière, 1909, Alpheus bouvieri A. Milne Edwards, 1878, Menippe nodifrons Stimpson, 1860, Pilumnus dasypodus Kingsley, 1879 and Petrolisthes armatus. Armases angustipes (Dana, 1852), Pachygrapsus transversus (Gibbes, 1850) and Panopeus occidentalis (Saussure, 1857) showed ovigerous females during the warm months, when the surface water temperature was equal or above 24oC, whilst Panopeus americanus Saussure, 1857 and Eurypanopeus abbreviatus Stimpson, 1860, equal or above 20oC. Despite of the constant occurrence of the porcelain crab Petrolisthes galalhinus (Bosc, 1801), it was not possible to infer its breeding period due to the absence of ovigerous females and the presence of juveniles only in a few samples.

Palabras llave : Temporal density distribution; decapod crustacean; rocky shore; Island of Farol; Paraná; Brazil.

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