RESUMO
The Caravelas River estuary and adjacent coastal region were studied during the rainy and dry seasons of 2003-2004 to assess the copepod community structure. Abiotic and biotic parameters were measured, and the total density, frequency and percentage of copepod taxa were determined for each sampling period. Copepod densities showed significant differences between sampling periods, with higher densities in the rainy seasons (Mean: 90,941.80 ind.m-3; S.D.: 26,364.79). The sampling stations located to the north and south, in the coastal region adjacent to the Caravelas River estuary presented the lowest copepod density values. The copepod assemblage was composed mainly of estuarine and estuarine/coastal copepods. The seasonal variations in temperature and salinity influenced the abundance of species during the rainy and dry seasons, with the following dominant species alternating: Paracalanus quasimodo Bowman, 1971 in the rainy season of 2003, Parvocalanus crassirostris Dahl, 1894 in the dry season of 2003 and Acartia lilljeborgii Giesbrecht, 1892 in the rainy and dry seasons of 2004. Non-parametric multidimensional scaling indicated differences in copepod assemblages between sampling periods, but not between sampling stations.
RESUMO
The copepod assemblage on the inner continental shelf adjacent to the coastal system of Camamu Bay (state of Bahia, Brazil) is described in relation to hydrographic conditions, during the wet and dry seasons of 2004. The zooplankton samples were obtained in vertical tows using a net with 200 µm mesh size. Temperature and salinity were measured, and the total density, frequency and percentage occurrence of the copepod taxa were determined for each sampling period. The highest densities were observed at the entrance of Camamu Bay (up to 7.473 ind.m-3), and the lowest on the adjacent inner continental shelf south of Camamu Bay (less than 500 ind.m-3). A total of 57 copepod taxa were identified. Paracalanus quasimodo Bowman, 1971, Subeucalanus pileatus (Giesbrecht, 1888), Clausocalanus furcatus (Brady, 1883), Corycaeus giesbrechti F. Dahl, 1894, Temora turbinata (Dana, 1849), Oithona similis Claus, 1866, Temora stylifera (Dana, 1849) and Nannocalanus minor (Claus, 1863) dominated numerically. The densities measured in both sampling seasons were significantly different: the means were 1.849 ± 1.922 ind.m-3 and 3.657 ± 3.170 ind.m-3 for the wet season and dry season, respectively. Depth and temporal variation in temperature and salinity influenced species abundance during the wet and dry seasons, with the dominant species alternating. Species richness and diversity increased on the inner shelf adjacent to the coastal system of Camamu Bay at the 30- and 50-m isobaths, suggesting that most species were oceanic in origin. The diversity was similar to other coastal systems of northeast Brazil.
RESUMO
The Caravelas River estuary and adjacent coastal region were studied during the rainy and dry seasons of 2003-2004 to assess the copepod community structure. Abiotic and biotic parameters were measured, and the total density, frequency and percentage of copepod taxa were determined for each sampling period. Copepod densities showed significant differences between sampling periods, with higher densities in the rainy seasons (Mean: 90,941.80 ind.m-3; S.D.: 26,364.79). The sampling stations located to the north and south, in the coastal region adjacent to the Caravelas River estuary presented the lowest copepod density values. The copepod assemblage was composed mainly of estuarine and estuarine/coastal copepods. The seasonal variations in temperature and salinity influenced the abundance of species during the rainy and dry seasons, with the following dominant species alternating: Paracalanus quasimodo Bowman, 1971 in the rainy season of 2003, Parvocalanus crassirostris Dahl, 1894 in the dry season of 2003 and Acartia lilljeborgii Giesbrecht, 1892 in the rainy and dry seasons of 2004. Non-parametric multidimensional scaling indicated differences in copepod assemblages between sampling periods, but not between sampling stations.
RESUMO
The copepod assemblage on the inner continental shelf adjacent to the coastal system of Camamu Bay (state of Bahia, Brazil) is described in relation to hydrographic conditions, during the wet and dry seasons of 2004. The zooplankton samples were obtained in vertical tows using a net with 200 µm mesh size. Temperature and salinity were measured, and the total density, frequency and percentage occurrence of the copepod taxa were determined for each sampling period. The highest densities were observed at the entrance of Camamu Bay (up to 7.473 ind.m-3), and the lowest on the adjacent inner continental shelf south of Camamu Bay (less than 500 ind.m-3). A total of 57 copepod taxa were identified. Paracalanus quasimodo Bowman, 1971, Subeucalanus pileatus (Giesbrecht, 1888), Clausocalanus furcatus (Brady, 1883), Corycaeus giesbrechti F. Dahl, 1894, Temora turbinata (Dana, 1849), Oithona similis Claus, 1866, Temora stylifera (Dana, 1849) and Nannocalanus minor (Claus, 1863) dominated numerically. The densities measured in both sampling seasons were significantly different: the means were 1.849 ± 1.922 ind.m-3 and 3.657 ± 3.170 ind.m-3 for the wet season and dry season, respectively. Depth and temporal variation in temperature and salinity influenced species abundance during the wet and dry seasons, with the dominant species alternating. Species richness and diversity increased on the inner shelf adjacent to the coastal system of Camamu Bay at the 30- and 50-m isobaths, suggesting that most species were oceanic in origin. The diversity was similar to other coastal systems of northeast Brazil.
RESUMO
The copepod assemblage on the inner continental shelf adjacent to the coastal system of Camamu Bay (state of Bahia, Brazil) is described in relation to hydrographic conditions, during the wet and dry seasons of 2004. The zooplankton samples were obtained in vertical tows using a net with 200 µm mesh size. Temperature and salinity were measured, and the total density, frequency and percentage occurrence of the copepod taxa were determined for each sampling period. The highest densities were observed at the entrance of Camamu Bay (up to 7.473 ind.m-3), and the lowest on the adjacent inner continental shelf south of Camamu Bay (less than 500 ind.m-3). A total of 57 copepod taxa were identified. Paracalanus quasimodo Bowman, 1971, Subeucalanus pileatus (Giesbrecht, 1888), Clausocalanus furcatus (Brady, 1883), Corycaeus giesbrechti F. Dahl, 1894, Temora turbinata (Dana, 1849), Oithona similis Claus, 1866, Temora stylifera (Dana, 1849) and Nannocalanus minor (Claus, 1863) dominated numerically. The densities measured in both sampling seasons were significantly different: the means were 1.849 ± 1.922 ind.m-3 and 3.657 ± 3.170 ind.m-3 for the wet season and dry season, respectively. Depth and temporal variation in temperature and salinity influenced species abundance during the wet and dry seasons, with the dominant species alternating. Species richness and diversity increased on the inner shelf adjacent to the coastal system of Camamu Bay at the 30- and 50-m isobaths, suggesting that most species were oceanic in origin. The diversity was similar to other coastal systems of northeast Brazil.
RESUMO
The Caravelas River estuary and adjacent coastal region were studied during the rainy and dry seasons of 2003-2004 to assess the copepod community structure. Abiotic and biotic parameters were measured, and the total density, frequency and percentage of copepod taxa were determined for each sampling period. Copepod densities showed significant differences between sampling periods, with higher densities in the rainy seasons (Mean: 90,941.80 ind.m-3; S.D.: 26,364.79). The sampling stations located to the north and south, in the coastal region adjacent to the Caravelas River estuary presented the lowest copepod density values. The copepod assemblage was composed mainly of estuarine and estuarine/coastal copepods. The seasonal variations in temperature and salinity influenced the abundance of species during the rainy and dry seasons, with the following dominant species alternating: Paracalanus quasimodo Bowman, 1971 in the rainy season of 2003, Parvocalanus crassirostris Dahl, 1894 in the dry season of 2003 and Acartia lilljeborgii Giesbrecht, 1892 in the rainy and dry seasons of 2004. Non-parametric multidimensional scaling indicated differences in copepod assemblages between sampling periods, but not between sampling stations.