[Distribution and abundance of demersal fishes and of some other marine benthic organisims on the continental shelf (0-60 m) of French Guiana].
In order to establish the distribution and abundance of demersal fishes and of some other benthic organisms on the continental shelf of French Guiana (western central Atlantic), ninety-five bottom trawls were effected at depths ranging from 0 to 60 m in October 1993. A total of one hundred and ten different species were identified including eight decapod crustaceans, two cephalopods, one sea turtle and ninety-nine fishes. Despite the high species richness in benthic macrofauna, most species showed a low count, and only twelve of them comprised more than 80% of total captures. This study has mainly highlighted the existence of a well-pronounced bathymetric zonation. This phenomenon would appear to be linked to environmental factors, especially salinity and substrate granulometry, which are greatly conditioned by fresh water and sediment flowing in large rivers such the Amazon River. The results revealed three distinct faunistic assemblages: a littoral (or shallow-water) community (0-30 m) distributed in coastal estuarine waters characterized by muddy bottoms, a middle-shelf community (30-50 m), and a lower-shelf community (depths > 50 m) distributed in deeper marine waters characterized by sandy bottoms.