Benthic samples were taken at 303 stations in the Ilha Grande region, down the isobath of 50 meters. In 12 of these Stations (20 samples) we found the brachiopod Bouchardia rosea (Mawe, 1823). The highest density observed for this species was 58 individuals/m². Its occurrence is related to sediments with less of 30% of granules smaller than 420 µ, without the fraction smaller than 44µ, to salinity higher than 35 and probably to the enrichement process due to nearness of islands and organic material carried from Sepetiba bay. Apparently, there are no relationship, between the lenght of the valve and the position of the station and with the depth. There are, apparently, a direct relationship with salinity and a inverse with temperature. There are a tendency of the median lenght of the valve, to decrease with the increase of the aggrefation of the species. There are, apparently, three generations of the individuals in the presently samples.
