Résultats des campagnes BIOGAS : 3 août 1972 - 2 novembre 1974

The study of abyssal benthic communities which begun at the Centre Océanologique de Bretagne in 1969 has been pursued during the seven cruises BIOGAS carried out from 1972 to 1974, devoted to the intensive exploration of a restricted area in the Gulf of Biscay. The frequency and total number of cruises conducted at different periods of the year enable to collect adequately large amonts of data in order to describe the faunal assemblages, to evaluate density and diversity of the fauna as well as assumed biological rythms. Six stations located on soft bottoms between 1800 m and 4700 min the north west and south east of the Gulf of Biscay have been choosen. Each station has been sampled several times with various types of gears each of them selecting a gi­ven size category of the total fauna (epibenthic sled, trawl, Reineck corer, baited trap). The whole set of data collected during the 220 sampling operations brought information on tapies such as : - physico chemical analysis of the sediment - sorting and counting of the biological material - photographie observations obtained close to the sea floor by means of "troïka" sledge and trap, which show some carnivorous species being at­tracted by the bait