Subsidient: Claire Filbri/Leiden University
Subsidie: S152.610

Human activities, such as vessel traffic may affect marine mammals and their habitat. The aim of this study was to assess if vessel usage affected dolphin group sighting locations of the resident indo-pacific bottlenose dolphin (Tursiops aduncus) population in the waters of the growing town of Bunbury, Western-Australia. From December 2014 to May 2015, we conducted boat-based surveys to determine dolphin sighting locations. From an elevated lookout we conducted vessel scan samples to record the position of each vessel. By spatially associating our data to 0.01° by 0.01° regions, we found that higher vessel intensity is significantly positively correlated with the number of dolphin sightings per region. Areas with an overall higher vessel intensity may overlap with preferred habitat for the dolphins. Some of the habitat with an overall high vessel intensity has been identified as critical habitat important for foraging and resting, and the benefits of staying in this habitat might outweigh the costs of the vessel disturbance. However, more research about the food availability and predation risk needs to be conducted to give explicit guidelines for management of the critical habitats of the dolphin population in Bunbury.