The effects of boat-based tourism on the behavioural budget of bottlenose dolphins and biological significance of these for welfare By Sian Cains Introduction Bottlenose dolphins are frequently exposed to boat-based dolphin watching due to their preference for costal areas (Constantine et al., 2004). The following three studies contribute to growing evidence that such interactions have a detrimental effect on the behaviour and, consequently, the energy demands and social cohesion of dolphins (Constantine et al., 2004). Discussion In the first study, Constantine et al. (2004) observed an isolated population of approximately 450 bottlenose dolphins in the Bay of Islands, New Zealand, to determine whether their transition between behavioural states altered in response to boat interactions. A small aluminium boat was used to observe the behaviour of the dolphins over 27 months, as well as the number and type of boats that came within 300m of a pod. The predominant behaviour of the dolphins within a group was determined using a focal scan and allocated one of eight behavioural states, including resting, milling, socialising and travelling. Using the CADMOD statistical model to analyse the data, it was found that, as the number of boats grew, milling behaviour increased (from 28% to 46%) and resting behaviour decreased (from 68% to 0.5%). These effects were amplified in small pod sizes and when coupled with irregular tour-boat departure times. These results ...