Trophic models of São Sebastião Channel and continental

Abstract. Two trophic models of the São Sebastião ecosystems were built to evaluate differences in their size and organization. The study area is located on the southeastern coast of Brazil. The trophic groups of the systems were based on ecologically or taxonomically related species, considering their relative abundance and similarity of diets and habits. The models, based on the Ecopath software, consist of six fish groups, ten invertebrate groups, Bacterioplankton, Phytoplankton, Zooplankton, and Detritus. Biomass, production, and consumption were estimated for the Inner shelf and the Channel. Primary production was estimated as 2,436 g wet weight m-2 year-1 on the inner shelf and 1,441 g WW in the channel. Total benthic production was 215.8 and 418.1 g WW.m-2.yr-1 on the inner shelf and the channel, respectively. Total fish production plus Cephalopoda was 4.9 g WW.m-2.year-1 in the inner shelf and 11.5 g in the channel. Total system throughput was 8161 g WW.m-2.year-1 in the inner shelf and 11442 g in the channel. The Channel ecosystem was slightly larger in total biomass, development capacity, cycling, and total throughput. Nevertheless, primary production, and total net primary production showed higher values in the inner shelf ecosystem. In contrast to other shelf systems, detritus pathways are more important than flows originating from phytoplankton, mainly in the Channel ecosystem