Brazilian Archives of Biology and Technology (Feb 2010)

Seasonal and spatial variability of appendicularian density and taxonomic composition in the Caravelas Estuary (Northeastern Brazil) and adjacent coastal area

  • Pedro Freitas de Carvalho,
  • Sérgio Luiz Costa Bonecker

DOI
https://doi.org/10.1590/S1516-89132010000100020
Journal volume & issue
Vol. 53, no. 1
pp. 161 – 169

Abstract

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This study aimed to identify and assess the seasonal and spatial variations of the appendicularians in the Caravelas River estuary and the adjacent coastal area. Samples were taken during 12 campaigns over five years (2001 and 2003-2006). Ten species were identified; the most abundant were Oikopleura dioica, Oikopleura rufescens, and Oikopleura longicauda. These species represented more than 95% of the total numbers of appendicularians. The remaining species were less frequent and occurred in low densities. The mean density of appendicularians found at the coastal stations (804 ind.m-3.) was higher than in the estuary (66 ind.m-3). However, the differences observed between the estuary and coastal stations were not significant (p=0.54). The samples taken during the dry season showed a higher mean density (587 ind.m-3) than in the rainy season (376 ind.m-3), and the differences between the seasons were statistically significant (p=0.004).Esse trabalho teve como objetivo identificar e avaliar as variações espaciais e sazonais das apendiculárias no estuário do rio Caravelas e área costeira adjacente (17º35' - 18º22' S e 39º8' - 39º55'W). As coletas foram realizadas em 12 campanhas durante cinco anos (2001 e 2003 - 2006). Foram identificadas dez espécies, sendo que Oikopleura dioica, O. rufescens e O. longicauda foram as mais abundantes. Estas três espécies representaram mais de 95% do total de apendiculárias coletadas. As outras espécies foram menos freqüentes e ocorreram em baixas densidades. A densidade média de apendiculárias encontrada nas estações e costeiras (804 ind.m-3) foi maior que na de estuário (158 ind.m-3). As diferenças encontradas entre as estações de estuário e costeiras não foram significativas (p=0,73). As campanhas realizadas durante o período seco apresentaram densidade média (587 ind.m-3) maior que do período chuvoso (376 ind.m-3). As diferenças entre os períodos chuvoso e seco foram estatisticamente significativas (p>0,01).

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