Spatial variation of plastic debris on important turtle nesting beaches of the remote Chagos Archipelago, Indian Ocean. (August 2022)

• Record Type: Journal Article
• Authors: Hoare, V.; Atchison Balmond, N.; Hays, G.C.; Jones, R.; Koldewey, H.; Laloë, J.-O.; Levy, E.; Llewellyn, F.; Morrall, H.; Esteban, N.
• Is Part Of: Marine pollution bulletin. Volume 181(2022)
• Publication Date: 2022-08
• Subjects: Marine pollution -- Coastal management -- Marine turtle conservation -- Coral reef atoll -- Litter management -- Beach clean; Marine pollution -- Periodicals; Marine Biology -- Periodicals; Water Pollution -- Periodicals; Mer -- Pollution -- Périodiques; Publications périodiques; Pollution des mers; Lutte antipollution; Electronic journals; 363.7394
• DOI: 10.1016/j.marpolbul.2022.113868
• Languages: English
• ISSNs: 0025-326X

Abstract

Abstract: We report Anthropogenic Marine Debris (AMD) in Chagos Archipelago in the Indian Ocean, globally amongst the most isolated island groups. AMD on 14 island beaches in five atolls were surveyed in 2019 using two techniques: Marine Debris Tracker (MDT) along littoral vegetation and photoquadrats in open beach. Over 60 % of AMD in both beach zones was composed of plastics, especially bottles and fragments (mean = 44.9 %, 27.2 %, range = 16.5–73.2 %, 4.8–55.9 % respectively in vegetation; mean = 28.7 %, 31.5 %, range = 17.7–40.7 %, 11.6–60.0 % respectively in open beach). The density of plastic debris in littoral vegetation (MDT data: 1995 bottles, 3328 fragments per 100 m 2 ) was 10-fold greater than in open beach (photoquadrat data: 184 bottles, 106 fragments per 100 m 2 ). Significant latitudinal variation in vegetation AMD occurred (8-fold greater in southern atolls, p = 0.006). AMD varied within island zones: most debris observed on oceanside beaches (oceanside vs lagoon, W = 365, p < 0.001; ocean vs island tip, W = 107, p = 0.034). Standardisation of surveys using the open-source MDT App is recommended. Debris accumulation hotspots overlapped with sea turtle nesting habitat, guiding future beach clean-up prioritisation. Graphical abstract: Unlabelled Image Highlights: Marine debris accumulated on all sandy beaches on 14 islands and 5 atolls of Chagos Archipelago, equatorial Indian Ocean. >60% debris was plastic bottles or fragments in open beach areas (28.7%, 31.5%) and littoral vegetation (44.9%, 27.2%). Plastic debris density in littoral vegetation was over ten-fold more than open beaches (1995 bottles, 3328 fragments 100 m −2 ). Marine debris density varied latitudinally and between beach zones (oceanside, lagoon-side, island tips). Debris hotspots overlap with critical turtle nesting habitat, informing beach clean-up prioritisation.