Temporal variation of the zooplankton from Tramandai Beach, RS, southern Brazil, with emphasis on Copepoda

Temporal variation of the zooplankton from Tramandai Beach, RS, southern Brazil, with emphasis on Copepoda. The temporal variability of density, species composition, biomass and diversity of the surf zone zooplankton from Tramandai Beach, RS, Brazil, was studied between August 2005 and August 2006. Samples were taken forthnightly using a zooplankton net of 150 cm total length, 50 cm mouth diameter and 300 mu m nylon mesh size. Data on clorofila-a, wind direction, longshore current, salinity, air and water temperature were taken as well. Copepoda presented the highest species diversity, being Temora turbinata (Dana, 1849) the species with higher relative abundance and frequency of occurrence. Other Copepoda species were also numerically important, such as Acartia tonsa (Dana, 1849), Subeucalanus pileatus (Glesbrecht, 1888) and Ctenocalanus vanus (Glesbrecht, 1888). The Mysidacea Metamysidopsis elongata atlantica (Bascescu, 1968) presented frequency of 58.33% and relative abundance of 44%. The peak of mesozooplanktonic biomass (96 mg.m(-3)) was recorded in September/2005, corresponding to the maximum density value presented for this species (3,535 org.m(-3)). Information about zooplankton of this region is scarce and the results of this study will provide a base for the knowledge about the biological processes occurring in the surf zone of Tramanda Beach.