Sea turtles are vulnerable to marine litter because they suffer lethal or sub-lethal effects when they confuse marine litter with food or when they get entangled in it (Mattidi et al. 2019). Currently, the amount of plastics entering the oceans is estimated to be between 4-12 million tons annually. The probability of sea turtles interacting with plastics are therefore high, especially in oceanic juveniles. Under the AZORLIT and LIXAZ projects, the COSTA team is investigating the ingestion of marine litter in turtles that appear dead in the region. So far, our results show that 83% of the individuals studied had ingested plastics (Pham et al. 2017).
COSTA is also involved in the European project INDICIT I & II, under the European Union Marine Strategy Framework Directive – MSFD , which aims to validate the use of sea turtles as indicators of the presence and impact of litter in the oceans (descriptor 10). Sea turtles are particularly vulnerable to marine litter with high rates of plastic ingestion. Monitoring litter ingestion by sea turtles can therefore serve as a tool to evaluate the efficiency of the measures being implemented to reduce the amount of litter entering the oceans. COSTA provides information to better understand and improve the limits and potential of using sea turtles as indicators.
