| A quantitative sampling was made on the non-cultivated molluscs of the soft bottom macrofauna in the bay of Marennes-Oleron. A stratified random sampling, including an optimal allocation strategy. provided adequate data to estimate abundance and biomass (total weight. dry weight and ash-free-dry weight) of each molluscan species. The main stratification factors were respectively the bathymetric levels. the different types of sediment and the differences between natural, oyster-free mud flats and cultivated areas. A Smith Mc-Intyre grab was used to sample the subtidal, shallow areas and the tidal flats as well. The total number of sampling stations was 370. The final estimation of the total weight of benthic molluscs was 14,400 ± 3,000 tons (at 95 %... |
