Distribution and abundance of debris on the continental shelf of the Bay of Biscay and in Seine Bay

The distribution and abundance of larger marine debris were investigated on the continental shelf of the Bay of Biscay and in Seine Bay during six oceanographic cruises undertaken from November 1992 to September 1993. Different types of debris were enumerated, particularly plastic bags and bottles, other plastic objects, metallic objects, glass and diverse materials including fishing gear. The results showed considerable annual and geographical variation in the Bay of Biscay, with peak abundance at the end of winter in an area off the Gironde Estuary where concentrations reached 14 debris per hectare. In all stations sampled, plastic bags accounted for a very high percentage (up to 95% or more) of total debris. In Seine Bay, only small amounts of debris were collected. All these results are interpreted with respect to hydrological conditions.