Marine litter ingestion related with debris entangling sea turtles in The Canary Islands

Abstract

The European Project INDICIT had proposed sea turtles as marine litter indicator on the European waters, using both litter ingestion and entanglement on marine debris. Standardized protocols have been developed for sampling and shared homogenized data collected in different European regions to conduct regional and global analysis. Standard protocols developed by INDICIT project has been used for sampling litter ingestion on stranded loggerhead turtles in Canary Islands from May 2018 to December 2020. In other hand, several data were collected from all stranded turtles according to the standard protocol implemented by the Canary Islands Government, including the stranding cause and litter causing entanglement, based on INDICIT protocols and litter classification approved by the European Commission. Aim of this study was to determinate if there exist a relation between the marine debris causing entanglement and the litter ingested by these turtles, based on the hypothesis that entangled turtles will try to remove debris causing entanglement by biting and ingesting them. Results showed that 100% of sea turtles stranded in Gran Canaria (both live and dead) presented marine litter ingested. The 63% of turtles analysed were stranded due to entanglement. The material causing entanglement were found ingested by more than the 50% of the animals analysed. These results will help us to have a better understand of the different hazards that marine debris could impact sea turtles and to know which turtles are most likely to have ingested marine litter.