Cuvier’s beaked whale atypical mass stranding event in Cypriot Coastline (2023)

Abstract

Strandings of Cuvier’s beaked whales (Ziphius cavirostris) have been regularly documented in the scientific literature in the Mediterranean Sea since 1823, mainly related to anthropogenic activities, particularly exposure to underwater sounds. The aim of this study is to present the findings of an atypical mass stranding event, which was first observed on February 9th 2023, in the coastal area of Cyprus, where eight (8) animals from the species Ziphius cavirostris, were stranded in the area over which the government of the Republic of Cyprus exercises effective control. All standings were distributed within Chrysochou Bay, between the areas of Polis Chrysochous and Pachyammos. Out of these eight (8) animals, seven (7) were stranded alive and one (1) washed ashore dead. The response team arrived at the stranding areas, and after primary assessment attempted at refloating the animals. Despite these efforts, all animals died by the next morning. Full necropsy, tissue and DNA samplings were performed where it was feasible. Systemic gas bubbles (embolism) were found within the cardiovascular system as well as in other organs, including gas bubbles within the blood collected from the heart cavities. Selective tissue samples from viscera and blubber were also collected and submitted for histopathology. In conclusion, gross and histological findings indicate that this atypical Cuvier’s beaked whales mass stranding event showed the characteristic features of a mass stranding due to acoustic related disturbance, probably associated temporally and spatially to mid-frequency sonar activities. This is another example of the adverse effects of underwater acoustic disturbances on beaked whales.