Drivers of litter ingestion by sea turtles: Three decades of empirical data collected in Atlantic Europe and the Mediterranean

• Published in: Marine Pollution Bulletin
• Main Authors: Darmon G., Schulz M., Matiddi M., Loza A.L., Tòmà s J., Camedda A., Chaieb O., Hili, Hedia A. El, Bradai, Mohamed N., Bray, Laura, Claro, Francoise, Dellinger, Thomas, Dell'Amico, Florence, Lucia, Giuseppe A. de, Duncan, Emily M. M., Gambaiani, Delphine, Godley, Brendan, Kaberi, Helen, Martin, Jessica, Moreira, Claudia, Ostiategui, Patricia, Pham, Christopher K., Piermarini, Raffaella, Revuelta, Ohiana, Rodriguez, Yasmina, Silvestri, Cecilia, Snape, Robin, Tsangaris, Catherine, Vale, Maria, Vandeperre, Frederic, Miaud, Claude, Kaska, Yakup, Sözbilen, DoÄŸan
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier Ltd 2022
• Subjects: Europe; Plastics; Turtles; Bio-indicator; Body condition; Health assessment; Marine litter impacts; Standard monitoring; Elastomers; Accurate analysis; Bio-indicators; Empirical data; Health assessments; Marine litter; Marine litter impact; Restoration measures; Sea turtles; Health; plastic; adult; animal tissue; Article; autopsy; body constitution; Caretta; environmental impact assessment; environmental monitoring; female; fishing; gastrointestinal content; geography; information processing; ingestion; life history trait; male; nonhuman; population dynamics; sea turtle; sex; Southern Europe; water pollution; animal; eating; turtle; North East Atlantic
• Online Access: https://hdl.handle.net/11499/47469; https://doi.org/10.1016/j.marpolbul.2022.114364

Sea turtles are considered as bio-indicators for monitoring the efficiency of restoration measures to reduce marine litter impacts on health. However, the lack of extended and standardised empirical data has prevented the accurate analysis of the factors influencing litter ingestion and the relationships with individual health. Historic data collected from 1988 and standard data collected from 2016 were harmonised to enable such analyses on necropsied loggerhead turtles (Caretta caretta) in eight Mediterranean and North-East Atlantic countries. Litter was found in 69.24 % of the 1121 individuals, mostly single-use and fishing-related plastics. Spatial location, sex and life history stage explained a minor part of litter ingestion. While no relationships with health could be detected, indicating that all individuals can be integrated as bio-indicators, the mechanistic models published in literature suggest that the high proportion of plastics in the digestive contents (38.77 % per individual) could have long-term repercussions on population dynamics. © 2022 European Commission, EC This study is part of the INDICIT (“Indicator Impact Turtle†2017–2019, n°11.0661/2016/748064/SUB/ENV.C2) and INDICIT II (Indicator Impact Taxa, 2019–2021, n°110661/2018/794561/SUB/ENV.C2) European projects. We are grateful to all stakeholders working in the field who have brought sea turtles, especially rescue centres, stranding networks and fishermen. We thank all the experts who took part in collecting data, improving the protocols, giving an advice on the parameters to measure. We also express our gratitude to the members of the INDICIT I and II External Advisory Board for their support and useful advice. We warmly thank the European Commission for its financial support to implement the INDICIT and INDICIT II projects. We also sincerely thank the reviewers whose comments enabled a clear improvement of the article.