For centuries, South Korea's legendary diving women have scoured the coastal waters surrounding Chejudo, an isolated and mythical volcanic island lying off the tip of the Korean Peninsula. Their aquatic lives traditionally began at the tender age of 10. Out in the choppy sea, their haunting whistles piercing the frosty air are audible from as far as a kilometre away as they rise for breath after skin-diving to depths of 18 metres in search of sea creatures. Shellfish and octopus are their usual prey. If they are lucky, the most lucrative harvests of all are a delectable, tiny cuttlefish known as nakji and much sought-after abalone. Their whistling anthem at the surface is called the sumbi-sori. It cries as they empty their lungs to gasp for air. When the sumbi-sori falls silent, the haenyeo women return underwater for another three or four minutes. They are a breed apart but there are no children joining the sturdy fold any more. The sole survivors of this disappearing world are today aged between 50 and 70 and, when the last of these diving women finally retire, the tradition is doomed to die with them. 'We are the last,' says Moon Chan-yeh, who, at the remarkable age of 72, is still diving from a rocky, windswept outcrop of Chejudo called Uto island. The explanation for the demise of the diving women is simple. 'This life is too hard for our daughters and grand-daughters,' Madam Yeh said. Cut off from the mainland for centuries on Chejudo, the diving women originally took to the water out of necessity. Farming the thin volcanic soil was futile. Nothing but peanuts grow on windy, desolate Uto island. A matriarchal society evolved as the haenyeo took to hunting beneath the waves for seafood, while their husbands stayed at home to look after the children and cattle (Uto island translates as cow island). 'When I was young,' said Madame Yeh, 'we had no choice. We had to dive to live. Today, the young girls like to dress up and work in an office or a tourist resort.' A decade ago, more than 10,000 diving women were trawling the underwater rocks off Chejudo. Today, fewer than 3,000 remain. Madame Yeh is determined to continue for as long as her health holds. But she is in her twilight years. 'I will not miss it,' said Madame Yeh, when asked about the day when she packs up her wetsuit for good. 'It is a very hard life.' There are also health hazards. The fact that a 72-year-old can spend four or five hours a day out in the ocean, diving for anything from 20 seconds to two minutes without breathing apparatus or scuba equipment, speaks volumes for the long-term benefits of daily exercise. But the haenyeo spend much of their lives suffering from respiratory complaints - a result of the intense, prolonged pressure exerted on their lungs. Most require daily medication. It was not until the 1970s that the diving women began to wear modern rubber wetsuits as protection against the chilly and sometimes icy waters. Until then, they braved the cold in skin-tight white cloth. Immortalised in folk songs and poems, the haenyeo dive within a rigid hierarchy. It is divided into three ranks according to experience and diving skills, beginning as Sang-kun, then graduating to Chung-kun and, ultimately, Ha-kun, the director of operations. Their harvest is sold through a network of fishermen's associations. But even allowing for the high prices of seafood these days in Northeast Asia, the haenyeo only earn around US$50 a day - a pittance compared to average salaries on the land. The tradition is fading and Madame Yeh does not regret it. Her six children work in Cheju City, the provincial capital just an hour's drive from Uto island, but across a far greater cultural divide between the past and the future of Chejudo.