Unusual mass mortality of cetaceans on the coast of the Turkish western black sea in summer 2009

Abstract

Between mid-July and early August, a series of cetacean strandings were reported on the 43km of the 200km-long Turkish western Black Sea coast between Yaliköy and Sile. During this mass mortality event, at least 114 cetaceans (harbour porpoises, bottlenose dolphins and common dolphins) were reported dead (2.7 individuals per km). Besides, eight common dolphins stranded alive. In the field study, total 23 cetacean specimens (7 bottlenose dolphins, 7 common dolphins, 6 harbour porpoises, 3 unidentified specimens) were found. Strandings per km were 2.9, 0.5, 0.07, 0.3 and 0.1 individuals for 2003, 2004, 2005, 2007 and 2008 all in early summer (June), respectively. The seasonal average of the strandings per km of 2008 was 0.1. Compared to these stranding rates in the past, the present event is considered to be an unusual one. As many individuals were at the advanced stage of decomposition due to heat, only two fresh common dolphin specimens were examined. Currently, different hypothesis are been taken into account and analysis are in progress.