The research status and trends on marine debris ingested by toothed whales: an attempt based on literature review and stomach-contents reanalysis

Abstract

Marine pollution, such as plastic debris, has become a significant environmental issue worldwide. Accidental ingestion by wild cetaceans has also raised wide concerns. For bioaccumulation through trophic linkages, cetaceans are recognized to be useful indicators for identifying marine pollution. This comprehensive review aimed to grasp the current status and research trends regarding the impacts of plastic pollution on cetaceans, focusing particularly on target species, areas, contact with fishing gear, and how such pollution causes the death of cetaceans. In addition, we thoroughly collected information on countermeasures for contamination necessary to improve survey methods for monitoring plastic pollution in cetaceans. We further analyzed stomach contents based on the historical whaling records and reported the current situation in the waters off Japan.