The Behavioural Impacts of Commercial Swimming With Whale Tours on Humpback Whales (Megaptera novaeangliae) in Hervey Bay, Australia

Stephanie H Stack,Grace L Olson,Kate R Sprogis,Jens J Currie,Florence A Sullivan,Abigail F Machernis

doi:10.3389/fmars.2021.696136

Abstract

Swim-with-whale tourism has expanded across several countries globally, with humpback whales (Megaptera novaeangliae) being the most commonly targeted species of baleen whale. Behavioural responses from humpback whales to swim-with-whale tours have been reported, however, responses are likely context-dependent. In 2014, swimming with humpback whales began in Hervey Bay, Queensland, Australia, an important resting ground and migratory stopover for humpback whales. The behavioural responses of humpback whales to this swim-with-whale industry have not been examined in Queensland, preventing informed management of this industry. The aims of this study were to: (1) examine short-term behavioural responses in whalesbefore, during, andafterswim-with-whale tours, and (2) investigate behavioural responses of whales throughout swim-with-whale tours compared to whale watch tours. Data were collected on board a commercial vessel, wherebefore, duringandafterdata were collected during swim-with-whale tours (250 h) and whale watch tours (150 h). Within the swim-with-whale tours, behavioural changes were detectedbefore, during, andafterthe vessel approached and placed swimmers in the water on a mermaid line, with the majority of significant changes occurring in theduringandafterphases. The number of direction changes made by the whales was highest when swimmers were in the water and the whales did not resume undisturbed behaviour after the swimmers exited the water. There was a 50% reduction in the proportion of time that whales spent resting during swim-tours compared to during whale watch tours. In both tour types, the time spent engaging in various behaviours was impacted by the distance between the vessel and the whale(s). These results support the conclusion that the behaviour of humpback whales in Hervey Bay was altered in response to swim-with-whale tourism. As humpback whales are capital breeders with limited energy reserves, reducing disturbance to them is of high importance for their continued population recovery and for the sustainability of the marine tourism industry. In Australia, where swim-with-whale tourism is becoming more established, robust education and enforcement programs, combined with continued monitoring of population dynamics through scientific research, are needed to minimise impacts to the population and guide adaptive management strategies.

Highlights

Whale watching has grown into a global marine industry that has created significant environmental, educational, scientific, and socioeconomic benefits for coastal communities around the world (Hoyt, 2001; O’Connor et al, 2009)
We examined short-term behavioural responses of humpback whales to swim-with-whale tours on a resting ground in Hervey Bay
Whales exhibited a higher frequency of direction changes and a 50% reduction in resting during swim-with tours compared to whale watch tours, demonstrating clear differences in the behavioural responses to the two tour types

Summary

Introduction

Whale watching has grown into a global marine industry that has created significant environmental, educational, scientific, and socioeconomic benefits for coastal communities around the world (Hoyt, 2001; O’Connor et al, 2009). Over the past few decades, as the interest and value of the industry has grown, commercial operations have diversified the ways in which they facilitate interactions between members of the public and whales and dolphins in the wild (Samuels et al, 2000; Hoyt, 2001; Rose et al, 2005). Humpback whales are commonly targeted as they are a cosmopolitan species and are easy to access as they migrate along coastal landmasses (Hendrix and Rose, 2014). The list of locations and targeted species continues to grow as the swim-with-whale industry rapidly expands around the world (Stack and Serra, 2021). The types of permitted approaches include floating at the surface with or without a tether, diving underwater on a breath hold and/or scuba diving (Stack and Serra, 2021)

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