October 15, 2010
Marine debris is a global concern that pollutes the world’s oceans, but little is known about the extent of this problem on the seafloor in deep water. The Habitat Ecology Team conducted the first quantitative study of man-made debris on the deep seafloor (20-365 meters) off central and southern California. Our study areas included submarine canyons and continental shelf rock outcrops and banks. Debris was observed and recorded during visual surveys of fishes and habitats using the manned submersible Delta and accompanying video cameras. We reviewed debris items from the archived videotapes for the period 1993-2007, and quantified information on sources, materials, and impacts of the debris.
Fishing activities were the most common source of debris. The highest density of debris was found off central California in 2007 (an average of 3.5 items/100 m), and had increased significantly since the 1990s (2.0 items/100 m). Recreational monofilament fishing line dominated this debris. Debris was less dense (0.2 items/100 m) and more diverse off southern than central California. Impact of debris to habitats and animals was low, and some debris was used as habitat by fishes and large invertebrates.
Plastic was the most abundant debris material. Removal of much of this debris from many of these remote seafloor habitats will not be practical, and therefore the plastics will likely persist in these dark, cold environments for centuries. This debris will continue to accumulate unless actions are taken to prevent it from being introduced into the marine environment.
Watters, D.L., M. Yoklavich, M. Love, and D. Schroeder. (2010) Assessing marine debris in deep seafloor habitats off California. Marine Pollution Bulletin 60:131-138.
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Keepers of the Deep
Video about deep water marine debris research off the California coast.
Contact: SWFSC Fisheries Ecology Division, Habitat Ecology Team