Cephalopod prey in the stomach contents of odontocete cetaceans stranded in the western Mediterranean Sea

Abstract

This study focuses on the occurrence of cephalopod prey in the stomach contents of 35 marine mammals, 19 Stenella coeruleoalba, 13 Tursiops truncatus, two Grampus griseus and one Ziphius cavirostris, stranded along the coast of Tuscany (western Mediterranean Sea) between 1990 and 2012. Cephalopod remains were identified to the lowest possible taxon. Overall, 569 individual cephalopods were identified, belonging to 12 families and 17 species. Most of the cephalopods belonged to the Ommastrephidae, Onychoteuthidae and Octopodidae. By species, the highest number of cephalopod species (n = 14) was consumed by S. coeruleoalba (our largest sample), followed by G. griseus (n = 7) and T. truncatus (n = 6). The only Z. cavirostris stomach examined contained just two species, both belonging to the genus Histioteuthis. The results indicated a possible partitioning of cephalopod resources among the sampled predators. Our results also provide new information on the presence of some rare and poorly known cephalopods in the area.

Key words:

• Beaks
• Cephalopoda
• Mediterranean Sea
• prey
• stomach contents
• toothed whales

Acknowledgements

The authors are grateful to Dr Patrizia Perzia for her technical support and to Mr Anthony Green for proofreading our English and suggesting improvements.

Editorial responsibility: Haakon Hop