Large numbers of tourists swimming with whales in Tonga are seriously disrupting their natural behaviour, according to new research.
The AUT University study, published in the scientific journal PLOSOne, shows that 80 percent of swim-with-whales activities focus on mother whales with new-born calves.
The research found mother whales increased their dive time and separated from their calves more frequently while people were snorkelling nearby.
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Tourism activities around mother-calf pairs are obviously disturbing them, the research found, which is concerning given how critical the first few months of a whale's life are.
Regulations on whale tourism in Tonga designed to protect the animals is also not enforced well enough, according to the study.
"The behavioural responses documented in this study underlie the risk of detrimental effects on this population of whales targeted by swim-with-whale tourism. The rapid growth of swim-with-whales industry experienced by Vava'u over a short period of time and the tour operator focus on mother-calf pairs is concerning, especially in the light of the poor compliance with regulations and the lack of enforcement of formal regulations documented by this study," the research states.
"Evidence from other studies on the effects of cetacean based tourism suggests that the findings from our study in Vava'u should be cause for concern.
"Our findings reinforce the urge for a more cautious and effective approach to the management of swimming activities with humpback whales, both for Tongan authorities and other governments willing to permit these activities."
The research was conducted by Lorenzo Fiori, Emmanuelle Martinez, Mark B Orams and Barbara Bollard.