Distribution of Anthropogenic and Natural Debris on the Mainland Shelf of the Southern California Bight

Various studies have been conducted to quantify debris found along beaches; however, little information has been compiled about debris found on the seafloor. This study describes the distribution, types, and amounts of marine debris found in the Southern California Bight (SCB) in July and August of 1994. Anthropogenic debris was most common in the central region, on the outer shelf, and in areas near publicly owned treatment works (POTWs). Fishing gear was the most common type of anthropogenic debris in the central region and in the outer shelf zone, whereas glass bottles and plastic were most common in POTW areas. Natural debris was more common close to shore in the inner shelf zone than anthropogenic debris. The deeper distribution of anthropogenic debris relative to natural debris, as well as the types of debris, suggest that the primary source of anthropogenic debris is marine vessel and fishing activity.