Dolphins, as long-lived animals with a complex fission-fusion
social structure, may respond to interactions with boats in many
different ways (Mann et al., 2000). The results of this study showed
that the type, number, and distances of boats affected behaviour
states of Indo-Pacific bottlenose dolphins in Port Stephens. There
was no resting, less feeding and socialising, and more milling and
travelling when dolphin-watching boats were present to within
100 m. When these changes were converted into activity budgets
(Fig. 2) they showed a similar trend to that reported in Allen et al.
(in press) for the same dolphin population five years earlier. The
earlier study was methodologically different as Allen et al. (2007)
conducted shore-based observations with binoculars and a scope
and examined only general characteristics, such as group formation
and direction. In the current study, we were able to distinguish
between the distance and number of dolphin-watching boats
present with a group of dolphins. With this sampling design, which
incorporated more rigorous data collection and more behavioural
parameters through focal follows, it was possible to detect an
absence of resting in the presence of tour boats.