As he gently lowers a fishing net into an azure lagoon, Saponkit Klatalay concedes he no longer roams the waters for days and nights like generations of sea gypsies before him, but prefers to sleep on the Thai mainland where he was resettled after the 2004 tsunami.

His village of "Chao Lay" sea-people drew on their ancestors' knowledge to survive the deadly waves, but the disaster has also thrust modernity upon his community and hastened their drift from the centuries-old seafaring traditions that saved their lives.

After securing the trap for his next catch, Saponkit points towards a line of wooden houses on stilts skirting the shore of tiny Koh Phra Thong island, his former home off southwestern Phang Nga province.

"All you can see is new. When the tsunami struck, all of this was destroyed," said the 36-year-old, who was evacuated to the mainland Khura Buri district some 10 kilometres (six miles) away, after the disaster that killed 5,395 people in Thailand alone.

Scores of houses and fishing boats were decimated but he says all 500 Chao Lay -- a marginalised group of once-nomadic hunter-gatherers -- survived in his village after spotting early tsunami signs thanks to the stories imparted by village elders.

"They said the water would recede, the colour (of the sea) would change, and the birds and other animals would start acting differently," the sea gypsy said, admitting until December 26, 2004 he "didn't believe it".

But reading the signs gave him enough time to find his children, warn neighbours and race towards the centre of the island to escape waves towering as high as four metres (13 feet).

On the worse-hit western and southern sides of the isle more than 100 others died -- mostly Thais and Myanmar migrants, but also a few foreign tourists and Chao Lay.

- Disappearing culture? -

Thailand's estimated 12,000 Chao Lay belong to three different ethnic groups -- the Moken, the Moklen and the Urak Lawoi -- who once led nomadic lives navigating the seas off the Andaman Coast but have increasingly adopted new jobs on the mainland, where they often face discrimination.

Even those still living off the sea have become more sedentary in recent decades with Moklen families -- such as Saponkit's -- building houses along island coasts, using them as a base from which to trawl the ocean for fish, shrimps and sea cucumbers in trips that sometimes last a week.

Since the tsunami, when most families from his village were resettled in gleaming new charity-built houses in Khura Buri and granted their first-ever land deeds, Saponkit only fishes for one day at a time.

He now supplements his fishing income of less than 5,000 baht ($150) a month with odd jobs such as gardening on the mainland -- and more recently as chairman of the council on his former island home.

"If there was no tsunami I would never have become a local government official because Chao Lay were looked down upon," says Saponkit, who prefers mainland life for the educational opportunities it gives his three children.

- Traditional knowledge -

The pale-blue village school where he once studied, extended by two storeys with the donations that poured in post the tsunami, teaches pupils up until the age of 15.

Yet the new classrooms stand deserted as numbers plummeted when the Chao Lay departed en masse a decade ago.

Of the three Chao Lay groups, the more traditional Moken -- skilled free-divers who, unlike other humans, can focus underwater without masks -- are the best-known after they caught international headlines for saving tourists as well as themselves during the 2004 tsunami.

After interpreting the signs of the impending wave, some urged holidaymakers to flee to higher ground while those that were ferrying tourists on boat trips moved to deeper waters which they sensed would be safer than the shore.

The burgeoning profile of Chao Lay traditional knowledge, passed down orally through the generations, prompted the Thai cabinet in 2010 to pass a resolution setting out a policy to protect their way of life.

But experts say that while the move has helped to revive sea gypsy dance and music it has done little to promote indigenous knowledge.

"It has been proved by the tsunami they knew things we did not. There is much more we can learn from them," said Narumon Hinshiranan, an anthropologist at Chulalongkorn University in Bangkok.

The rise of mass tourism, a ban on hunting in newly protected marine parks and the depletion of fish stocks have made it increasingly difficult for Chao Lay to maintain traditional lifestyles.

Yet despite the challenges semi-nomadic communities persist -- the Moken moored on the Surin islands were also evacuated to nearby Khura Buri after the tsunami -- but failing to adjust to modern life they quickly returned home.

- 'Compete for everything' -

Inside their detached houses in Thepparat village, where some of the island-living Chao Lay were resettled, other tsunami evacuees however are embracing new found creature comforts.

Fears over losing their traditions, for this group of Chao Lay at least, appear to be trumped by the security of modern life.

"I feel safer here. We are closer to the fish market and life is easier," said Saponkit's mother, 63-year-old Arom, pointing out her first-ever washing machine and gas stove.

Hanging above the blaring television set -- another first -- is a framed photograph of Saponkit in a crisp, white uniform taken shortly after his appointment as council chairman.

The new position has boosted both his status and that of his family.

"In the next 10 years people will know if a person is Chao Lay or not only by his surname," said Saponkit, whose youngest child was born by his new Thai partner.

Yet despite his enthusiasm for the future, Saponkit admits modern life carries new pressures too.

"I have to compete for everything. When I go fishing, it's only me. I don't have to compete with anyone. Only myself," he says.