Do loggerhead sea turtle (Caretta caretta) gut contents reflect the types, colors and sources of plastic pollution in the Southwest Indian Ocean?

Margot Thibault; Ludovic Hoarau; Laurent Lebreton; Matthieu Le Corre; Mathieu Barret; Emmanuel Cordier; Stéphane Ciccione; Sarah-Jeanne Royer; Alexandra Ter Halle; Aina Ramanampamonjy; Claire Jean; Mayeul Dalleau

doi:10.1016/j.marpolbul.2023.115343

Do loggerhead sea turtle (Caretta caretta) gut contents reflect the types, colors and sources of plastic pollution in the Southwest Indian Ocean?

Mar Pollut Bull. 2023 Sep;194(Pt A):115343. doi: 10.1016/j.marpolbul.2023.115343. Epub 2023 Jul 31.

Authors

Affiliations

¹ UMR ENTROPIE, University of Reunion Island, 15 Avenue René Cassin, BP 7151, 97715, Saint Denis, Reunion Island, France; Centre d'Étude et Découverte de Tortues Marine (CEDTM), Saint-Leu, Reunion Island, France; The Ocean Cleanup, Rotterdam, the Netherlands; Kelonia, The Marine Turtle Observatory of Reunion Island, 46 rue du Gal de Gaulle, Saint-Leu, Reunion Island, France; CNRS, Université Toulouse III, Laboratoire des Interactions Moléculaires et Réactivité Chimique et Photochimique (IMRCP), UMR 5623 Toulouse, France. Electronic address: [email protected].
² UMR ENTROPIE, University of Reunion Island, 15 Avenue René Cassin, BP 7151, 97715, Saint Denis, Reunion Island, France; Centre d'Étude et Découverte de Tortues Marine (CEDTM), Saint-Leu, Reunion Island, France.
³ The Ocean Cleanup, Rotterdam, the Netherlands.
⁴ UMR ENTROPIE, University of Reunion Island, 15 Avenue René Cassin, BP 7151, 97715, Saint Denis, Reunion Island, France.
⁵ Kelonia, The Marine Turtle Observatory of Reunion Island, 46 rue du Gal de Gaulle, Saint-Leu, Reunion Island, France.
⁶ Osu-Réunion, University of Reunion Island, 15 Avenue René Cassin, BP 7151, 97715, Saint Denis, Reunion Island, France.
⁷ CNRS, Université Toulouse III, Laboratoire des Interactions Moléculaires et Réactivité Chimique et Photochimique (IMRCP), UMR 5623 Toulouse, France.
⁸ Association CETAMADA, Barachois Sainte Marie, Madagascar.
⁹ Centre d'Étude et Découverte de Tortues Marine (CEDTM), Saint-Leu, Reunion Island, France.

PMID: 37531795
DOI: 10.1016/j.marpolbul.2023.115343

Abstract

We analyzed plastic debris ingested by loggerheads from bycatch between 2007 and 2021 in the Southwest Indian Ocean (SWIO). We also analyzed plastic debris accumulated on beaches of the east coast of Madagascar as a proxy for ocean plastics to compare the characteristics of beached plastics and plastic ingested by turtles. We conducted a "brand audit" of the plastics to determine their country of origin. An oceanic circulation model was used to identify the most likely sources of plastics in the SWIO. In total, 202 of the 266 loggerheads analyzed had ingested plastics. Plastics categorized as "hard" and "white" were equally dominant in loggerheads and on beaches, suggesting no diet selectivity. Both the brand audit and circulation modeling demonstrated that Southeast Asia is the main source of plastic pollution in the region. This study demonstrates that loggerheads can be used as bioindicators of plastic pollution in the SWIO.

Keywords: Beach accumulation; Bioindicator; Caretta caretta; Dispersal model; Plastic debris; Source.

MeSH terms

Animals
Color
Indian Ocean
Plastics
Turtles*
Water Pollutants* / analysis

Substances

Plastics
Water Pollutants