Occurrence and pathologies associated with foreign body ingestion in stranded cetaceans, Canary Islands

Abstract

One of the major concerns in aquatic environment is the impact of marine litter. Plastic is the most prevalent item within marine litter and not only affects the chemical quality of the water but also impacts marine organisms. Currently, the presence of debris ingestion has been reported all over the world in different marine species, though little is known in cetaceans. In this research, we study the occurrence and pathologies associated with the presence of foreign bodies (FB) in stranded cetaceans in the Canary Islands during a sixteen years period (n = 465). Fifteen species were affected by FBs including eight out of the nine year-round species in the archipelago. A total of 36 individuals (7.74%; 36/465) presented at least one FB, being plastic the most common item found (80.56%). Deep divers were the most affected group with Grampus griseus as the most affected species followed by Physeter macrocephalus and beaked whales. Two individuals of baleen whales were also affected (Balaenoptera physalus and B. acutorostrata). Ingestion of debris was lethal in 36.11% (13/36) of the cases presenting lesions such as stomatitis, bleeding ulcers, gastritis, perforations and impactions. As previous reports, no lesions were found in ten individuals which presented ingested FB. This is the first forensic study that, based on statistical analysis, define two risk factors for FB ingestion (poor body condition and deep diving behavior) and a protective factor (adult age).