Ask a Scientist: What you should know before you go swimming with Humpback Whales in Tonga


It’s that time of the year again when humpback whales of the endangered Oceania population migrate from Antarctica to their mating, calving and nursing grounds in the South Pacific. Notably, the Kingdom of Tonga gained a reputation to be the “whale swim capital of the world” over the past years, and indeed it is one of the few places where close human-wildlife interactions are possible. The massive attention and interest of wildlife enthusiasts to travel to the remote archipelago Vava’u got fuelled by the dense coverage of images and videos on social media, provided by professional wildlife photographers as well as amateurs, who showcase their close and intimate encounters with the gentle giants on YouTube, Facebook and Instagram.

Swimming with whales is trendy. Times are behind us when swimming with dolphins distinct you from the crowd since everyone seems to get that ticked off their bucket lists by now. Swimming with whales is all about novelty, excitement and personal challenge – it’s something only a few of us were lucky enough to experience. The whale migration is an essential feature of the Pacific Islands, which, except for Aussies and Kiwis, are often too remote to be considered as a go-to destination. It’s because of the whales the islands are put on people’s radar. Compared to other destinations that also offer swim-with activities with humpback whales, Tonga has by far the most mature industry (est. in the early 1990s). But before you now rush to your browser to book your flights and swim tickets, there are some things you should consider before you go to Tonga to swim with humpback whales.

The latest publication of Fiori et al. (2019) investigated humpback whales’ behavioural responses to approaching vessels and swimmers and found some critical aspects that need to be communicated with potential participants of these activities in the destination Vava’u.

But first things first. In Tonga, humpback whales are approached as single individuals, groups of adult animals as well as mother-calf pairs. In general, global guidelines discourage from approaching groups of cetaceans that contain juveniles. E.g. this is the case in swim-with activities targeting dolphins in New Zealand. But why is that? Juvenile animals are often at higher risk to be involved in incidents because they are unfamiliar with boats and people around them. Further, they could get separated from their pods, which is the last thing responsible operators want to happen. In the South Pacific, interactions are conducted with animals that have just given birth, a time when bonding and nursing are critical for the calves’ survival.

In the study of Fiori and colleagues, it was noted that average diving time increased for mother-calf pairs when swimmers were present with diving being a well-known avoidance strategy displayed by various species of cetaceans. The disruption of resting behaviour, which generally takes place at or close to the surface, may have an impact on the calves’ growth rate. In simple words: baby gets no sleep, baby won’t grow or even worse, won’t survive…

In short: whether mothers with their babies should be targeted by such operations is debatable. It is done because they are more accessible than e.g. male singers. But here it’s about just because you can doesn’t mean that you should.

Another important finding of the introduced study is essential mind food for all of you who are into responsible wildlife experiences (which hopefully most of you are!):

The researchers revealed that there was low compliance with Tongan swim-with-whale regulations, including not considering the compulsory rest time of 1.5h between interactions with the same animal or groups of animals or the maximum number of swimmers in the water (generally not exceeding four swimmers and one guide). Further, up to 28 vessels were counted during the 2017 season alone. This is quite a lot considering that many people seek for intimate encounters with fewer people around.


So shall we leave swim encounters with nursing humpback whales altogether? Maybe. But first it’s always good to look for alternatives, that means places, which are low-key with only a few licensed operators, who follow regulations and therefore are more sustainable. Plus, you’ll then really have the chance for an experience you may only have to share with a handful of other people instead of crowds who kick each other’s masks off (no kidding, people do that).

If you have booked your trip to Tonga already, look for the right operators. The ones who respect the animals and their livelihoods. It is NOT about your experience (sorry, folks!), but the whales. It’s a critical habitat for an endangered species and this needs to be respected. For the love of whales.