Investigating the presence and foraging behaviour of the harbour porpoise (Phocoena phocoena) at the Blasket Islands Special Area of Conservation

Ana Margarida Rolim

The Blasket Islands are located in western Ireland. The area was designated as a Special Area of Conservation (SAC) for the harbour porpoise (Phocoena phocoena) as part of the Natura 2000 network. The information regarding this species presence and habitat use in the area is in many aspects limited. The harbour porpoise emits stereotypic clicks easily differentiated from other toothed cetaceans, which makes it a suitable candidate for acoustic monitoring. Through the use of hydrophones (C-PODs), this study aimed to investigate the occurrence and foraging behaviour of harbour porpoises at two locations (Wildbank and Inishtookert) in this SAC. Harbour porpoises were detected throughout the whole study period and variations across the deployment sites and the environmental cycles were identified. The results suggested that there were differences in the presence and foraging behaviour within the geographic scale of the SAC. Furthermore, there was an indication that harbour porpoises remained for longer periods in the area when foraging. Currently, there is no management plan regulating the Blasket Islands SAC. The findings of this study could be used to inform the creation and implementation of a management plan for this SAC.