The zooplankton of Santa Catarina continental shelf in southern Brazil with emphasis on Copepoda and Cladocera and their relationship with physical coastal processes

Very few studies have been carried out to exclusively investigate the zooplankton community of Santa Catarina State continental shelf, despite the economic and ecological importance of the area. This coastal region of southern Brazil presents highly relevant oceanographic processes, such as the strong influence of continental inputs, resurgence in the Cabo de Santa Marta Grande and River Plata plume water to the south. Two sampling cruises were carried out, in December 2005 and May 2006, in order to study temporal hydrological variations, and their influence on the biota of the region. Zooplankton samples for analysis were obtained by oblique hauls with Bongo nets at 33 sampling stations arranged in profiles perpendicular to the coast on each cruise. The predominant groups found in the samples were Copepoda, Cladocera, Salpidae and Chaetognatha, which presented higher densities at the stations closer to the coast. In the case of the December 2005 cruise, the salinity and temperature gradients perpendicular to the coast, promoted by the continental inputs to the north of the area and by the upwelling to the south, determined the limits of distribution of Acartia lilljeborgi and Penilia avirostris. However, the temperature and salinity gradients longitudinal to the coast determined on the May 2006 cruise did not explain the species distribution, indicating that biotic forcing mechanisms may have been active in the ecology of the system during this period.