title: Factors influencing the detection of beach plastic debris.
abstract: Marine plastic pollution is a global problem with considerable ecological and economic consequences. Quantifying the amount of plastic in the ocean has been facilitated by surveys of accumulated plastic on beaches, but existing monitoring programmes assume the proportion of plastic detected during beach surveys is constant across time and space. Here we use a multi-observer experiment to assess what proportion of small plastic fragments is missed routinely by observers, and what factors influence the detection probability of different types of plastic. Detection probability across the various types of plastic ranged from 60 to 100%, and varied considerably by observer, observer experience, and biological material present on the beach that could be confused with plastic. Blue fragments had the highest detection probability, while white fragments had the lowest. We recommend long-term monitoring programmes adopt survey designs accounting for imperfect detection or at least assess the proportion of fragments missed by observers.
authors.affiliation: RSPB Centre for Conservation Science, Royal Society for the Protection of Birds, The Lodge, Sandy, Bedfordshire, SG19 2DL, United Kingdom; Institute for Marine and Antarctic Studies, University of Tasmania, 20 Castray Esplanade, Battery Point, Tasmania, 7004, Australia. Electronic address: Jennifer.Lavers@utas.edu.au.
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Lavers
authors.affiliation: RSPB Centre for Conservation Science, Royal Society for the Protection of Birds, The Lodge, Sandy, Bedfordshire, SG19 2DL, United Kingdom.
authors.forename: Steffen
authors.initials: S
authors.lastname: Oppel
authors.affiliation: RSPB Centre for Conservation Science, Royal Society for the Protection of Birds, The Lodge, Sandy, Bedfordshire, SG19 2DL, United Kingdom.
authors.forename: Alexander L
authors.initials: AL
authors.lastname: Bond
mesh_terms: D001493:Bathing Beaches / Q000706:statistics & numerical data; D004784:Environmental Monitoring; D010969:Plastics / Q000032:analysis*; D014866:Waste Products / Q000032:analysis*; D014873:Water Pollutants / Q000032:analysis*; D014876:Water Pollution / Q000706:statistics & numerical data*
chemical_list: D010969:Plastics; D014866:Waste Products; D014873:Water Pollutants
keywords: Beach clean-up; Detection probability; Marine debris; Observer effect; Plastic pollution