Nature-based tourism and the behaviour of Bottlenose Dolphins Tursiops spp. in Port Phillip Bay, Victoria, Australia

Nature-based tourism targeting cetaceans is a billion dollar industry that continues to grow. Therefore, the ecological effects of this industry require investigation. Inshore marine wildlife, such as coastal populations of dolphins that have become tourism targets, is affected by human activities in the coastal zone, and tourism may be an additional stressor. The focus of marine wildlife tourism in southern Port Phillip Bay, Victoria, Australia, is a coastal population of bottlenose dolphins (Tursiops spp.). Commercial dolphin-swim and dolphin-watch operations seek out dolphins. This study monitored activity budgets of bottlenose dolphins at one site, in the presence and absence of vessels during a two-year period through land-based observations. The results demonstrate a significant decreased likelihood of bottlenose dolphins engaging in feeding behaviour when vessels were present. Schools with calves were significantly larger than groups without and vessel presence resulted in larger schools regardless of school composition. Results also indicated that the number of dolphins observed at the study site were lower during afternoon ebb tides and on afternoon slack tides. The significance of their reduced feeding in the long-term conservation of these dolphins will remain unclear until information is available on their behaviour in areas into which tourist operators do not venture