Abstract

The density, biomass, diversity and species richness of macrofaunal benthic (>500 μm) in oxic environment (>0.5 ml L') off Bay Coliumo (36°32'S, 72°57'W), Chile were analyzed. One transect of five stations between 3.6 and 22.5 m of depth were collected samples of sediments with a dredged Van veen of 0.051 m 2 a board R/V Kay-Kay in August (winter) of 2004. From sediment sample the organic matter percent, size of grain, density and biomass of the macrofauna were determined. Additionally, were taken water column samples for analyses of dissolved oxygen of bottom, temperature and salinity. The densities of macrofauna fluctuated between 1,111 and 11,183 ind m 2. While the values of biomass to reached 9.9 and 252.86 g m 2. For all macrofauna 29 species were identified. The highest values of diversity (3.23) coincided with lowest values of dominance and evenness. The parameters of diversity did not show a lineal relationship with depth. The polychaetes were dominant group (51.8%) followed by the crustacean (41%) and molluscs (6. 8%). In addition, through of analysis of BIOENV observed that percent of sand and content of organic matter are the main environment factors that regulate the communities structure of macrofauna off Bay Coliumo.