Influence of trawling on the behaviour and spatial distribution of Indo-Pacific bottlenose dolphins (Tursiops aduncus) in Moreton Bay, Australia

Abstract

Sympatric communities of inshore Indo-Pacific bottlenose dolphins (Tursiops aduncus) have previously been identified within Moreton Bay, southeast Queensland, Australia. The two communities overlap in distribution, yet are almost completely socially segregated and forage in distinctly different ways. The correlation between this social segregation, the different foraging strategies, and a human activity (trawling) has previously been demonstrated. This paper investigates the possible effects of trawling on the behaviour and spatial distribution of these two communities. A geographical information system is used to determine the spatial use of each community. The behavioural budgets of both communities showed significantly higher levels of foraging behaviours than reported for most other bottlenose dolphin communities. The spatial use of both communities changed seasonally. These results provide further detail on how human activities may indirectly influence the behaviour and spatial use of free-ranging marine wildlife.