Effects of swim-with-dolphin tourism on the behaviour of a threatened species, the Burrunan dolphin Tursiops australis

Ne Filby,F Christiansen,Ka Stockin,C Scarpaci

doi:10.3354/esr00826

Abstract

Burrunan dolphins Tursiops australis are frequently targeted by tourism operations in Port Phillip Bay, Australia. This study aimed to provide first insights into whether swim-with-dolphin (SWD) vessels in Port Phillip Bay affect the behaviour of Burrunan dolphins via the use of Markov chain models. The presence of SWD vessels affected dolphins' travelling, foraging, milling and socialising behaviours. The time dolphins spent foraging in the presence of SWD vessels was significantly reduced, with average foraging bout length decreasing by 13.6%, foraging recovery time increasing by 47.6%, and the probability of transitioning from foraging to milling increasing 4-fold. Conversely, dolphins spent significantly more time milling and socialising in the presence of SWD vessels. The reduction in time spent foraging when SWD vessels are present could lead to a decrease in dolphins' rate of energy acquisition, whilst the increase in milling could increase their energy expenditure. Collectively, this may lead to reduced biological fitness with population level consequences. However, although the short-term behavioural budget of the dolphin population was significantly affected, SWD vessels did not significantly affect the cumulative (i.e. yearly) behavioural budget of Burrunan dolphins. Thus, the assumption that boat-based cetacean tourism has major negative effects on targeted populations may be flawed in some cases.

Highlights

Cetacean-based tourism is one of the fastest growing global industries, occurring in over 119 countries (Hoyt 2001)
This study aimed to determine whether SWD vessels in Phillip Bay (PPB) affect the behaviour of Burrunan dolphins
Significant short-term changes in the behaviour of Burrunan dolphins were detected as a consequence of interactions with SWD vessels

Summary

Introduction

Cetacean-based tourism is one of the fastest growing global industries, occurring in over 119 countries (Hoyt 2001). Short-term responses of cetaceans to boat-based tourism include changes in behaviour (Lusseau et al 2009, Steckenreuter et al 2012, Christiansen et al 2013, Meissner et al 2015), swim speed and direction (Nowacek et al 2001, Timmel et al 2008, Christiansen et al 2014), respiration and dive characteristics (Janik & Thompson 1996, Lusseau 2003b, Ng & Leung 2003, Richter et al 2006), group cohesion (Bejder et al 1999, Hastie et al 2003, Tosi & Ferreira 2009), communication (Scarpaci et al 2000a) and habitat use (Bejder et al 1999, 2006a, Courbis & Timmel 2009). This is of particular concern for endangered species, such as the Burrunan dolphin Tursiops australis

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