A study on the Beibu Gulf ecosystem found that benthic invertebrates play a key role in transferring energy to higher trophic levels. Marine mammals occupy the highest trophic level in the food web. The system is dominated by a detrital path, with phytoplankton as the primary producer. The ecosystem is still developing and unstable, with a low bioproduction compared to net primary production. The model estimated a biomass density of commercially utilized species at 8.7 t x km(-2).