Low densities of macroplastic debris in the Pitcairn Islands Marine Reserve

Beaches on Henderson Island, one of the Pitcairn Islands in the central South Pacific, have been reported to have some of the highest standing stocks of stranded plastic recorded. Surveys of floating debris at sea show that this is not related to high densities of plastic in the area. Only 19 macroplastic items were observed during 905 km of at-sea transects (0.5 items·km−2; 135 g·km−2). This low density confirms previous microplastic surveys which show that the Pitcairn group lies west of the South Pacific Gyre. Plastic loads on beaches at other islands in the Pitcairn group are not exceptional. The east coast of Henderson Island appears to be particularly effective at accumulating drifting debris, but many small plastic fragments on these beaches probably result from degradation in situ, so removing macroplastics will reduce the formation of microplastics. [Display omitted] •The Pitcairn Islands Marine Reserve is one of the largest MPAs in the world.•Despite high plastic loads on some beaches, densities of macroplastics at sea are low.•Plastic loads at most islands in the Pitcairn group are not unusually high.•Removing stranded macroplastics will reduce the formation of microplastics.