From a sailor in the south Pacific:
The southern humpback whale lies suspended vertically near the surface just metres away from me, its ghostly white underside silhouetted against the deep blue of the Pacific Ocean. The giant mammal is nearly 16 metres (50 feet) long and weighs around 3.5 tonnes, but a gentle flick of its huge tail is enough to propel it gracefully back into the deep, leaving me bobbing on the surface.
My first experience of swimming with whales in waters off the northern Tongan island of Vava'u lasts only several minutes. Although a pair of adult humpbacks are still around, I want to sit somewhere quiet on the boat for a few minutes to store the astonishing encounter in my mind. Some whale watching companies do not allow their clients to swim with whales and believe the practice should be banned. - .. .
Later, I slip back into the water, a minnow next to the gentle giant that glides past me within 10 metres, its eye meeting mine with momentary curiosity.
Despite their massive size, the humpbacks move with languid grace. While we are vulnerable to their power, they appear relaxed in our presence, showing neither fear nor aggression. The curious giants lolled around our boat for at least 90 minutes in an unusually long encounter that thrills two BBC natural history cameramen on board.
'Watch the tail! Watch the tail!' skipper Allan Bowe yells as one swimmer drifts too close to the whale's massive tail. Later he says whales appear to be careful to avoid hurting swimmers.
'They know you’re there, they’re looking at you.' - .. .
'They know you're there, they're looking at you. If they wanted to hurt you, if they smacked that tail on you, you're gone, you're dead,' he says, adding none of his clients have been injured.
Tonga is one of a few countries in the world where it is possible to swim with whales. Others countries include the nearby South Pacific state of Niue and the Dominican Republic in the Caribbean.
Each year, southern humpback whales migrate thousands of kilometres from their summer feeding grounds in Antarctic waters to the tropics, where they mate, and the females return to give birth about 11 months later. Bowe estimates about 200 whales gather in the waters around lush Vava'u and 60 smaller islands nearby.
'Watch the tail! Watch the tail!' - .. .
The massive humpbacks, making a comeback from near extinction before a worldwide commercial hunting moratorium introduced in 1982, usually arrive in Vava'u in late July and leave about three months later.
Some argue swimming with whales is disruptive, particularly for mothers with calves, but Bowe disagrees.
'What I find annoying and frustrating is the arguments coming from people overseas, they haven't been here and been in with the whales,' he says.
'It's not in our interest to harass the animals, they are our livelihood.'
Bowe, a former fisherman and charter boat owner in his native New Zealand, pioneered swimming with whales after impetuously jumping in the water with a pair soon after he arrived in Vava'u in 1992.
'I found I couldn't tell people about it when I got out of the water.'
'Their beauty, their gracefulness, the lack of fear in something we've nearly hunted to extinction.
'There's just something there that I connected with and I've never found it anywhere else.'
Idyllic Sailing waterways of Tonga - the whales are just a bonus - .. .
Bowe started his Whale Watch Vava'u business in 1993 and others quickly followed in offering swimming with whales trips.
The Tongan government has since set a limit of 13 operators, each allowed only two boats, along with rules aimed at preventing harassment of the whales.
Another whale watching company, Whale Discoveries, run by Canadians Doug and Sharon Spence, do not allow their clients to swim with whales and believe the practice should be banned.
The couple, who first came to Vava'u 18 years ago, say they worry about the well-being of the animals and of the swimmers.
'Some have quite a close encounter and we have no doubt it's a fantastic experience and for many a very emotional experience,' says Sharon Spence.
'It could be argued that if you offer that kind of experience to the general public, then you're creating a passion for the whales that could ultimately save the whales.'
But they say some 'cowboy' operators -- and they exclude Bowe from that category -- flout the rules, stressing the whales.
They also worry about the risk of swimmers being attacked by tiger sharks.
A young US Peace Corps volunteer was killed two years ago by a tiger shark in the sea off Vava'u, although she was not swimming with whales.
Another man was seriously injured by a tiger shark six years ago while swimming with whales, prompting the government to ban swimming with whales for about two months.
Bruno Toke, head of the Tongan Visitor's Bureau in Vava'u, says he is worried about the possibility of another shark attack.
'I fear if that happens again, the government might stop it completely.'
If swimming with whales was banned, whale watching in Tonga would lose its near unique status and visitor numbers would fall, he says.
'That you can swim with the whales here is very, very important for tourism. I've done it once, it's just an awesome experience.'
As well as the 1,400 who come by yacht to Vava'u each year, another 8,000 come as normal tourists, and swimming with whales is the prime attraction in the pristine waters, ahead of diving, sailing and fishing.
