The influence of upwelling on the diversity and distribution of marine shrimp (Penaeoidea and Caridea) in two tropical coastal areas of southeastern Brazil

Two coastal locations situated inside and outside an upwelling area were investigated to assess the influence of environmental factors on the structure of marine shrimp assemblages. The locations were Macae in the state of Rio de Janeiro (RJ), influenced by upwelling from Cabo Frio (RJ), and Ubatuba in the state of Sao Paulo, with no upwelling. Samples were collected monthly with trawl nets, in three sites in each location at depths of 5-20 m. The relationship between species abundance and environmental factors was tested by redundancy analysis. The total of 148,266 shrimp captured (102,832 from Macae and 45,434 from Ubatuba) included 15 species, 13 genera, and 7 families. The caridean Periclimenes paivai was collected for the first time on the RJ coast, expanding its known geographical distribution. Higher richness and J' and H' values were obtained in the location under upwelling influence (Macae). Environmental variables (granulometric composition and organic-matter content of sediment, bottom temperature, and salinity) were associated with the abundance of shrimp. Our results suggest that sediment type and temperature are among the most important variables affecting seasonal distribution of the species. However, other factors such as intraspecific migration might have also influenced the observed patterns.