FOR U Win, born in a village on Inle Lake, fishing is a way of life. He is out most days in his small boat from morning until night in search of fish to sell at local markets.

But making a living is more difficult these days.

“Fish have become rarer in the last three or four years,” he said. With five children to support, he now raises pigs to make ends meet. Others from his village are doing the same, he said.

Renowned for its natural beauty and unique culture, including the famous one-legged rowing technique used by local boatmen, Inle Lake in Shan State is a national treasure and a major tourist draw.  The lake is also home to about 25,000 people – many from the native Intha group – who have lived along its shore for centuries.

Now conservationists say their homeland is in danger.

Sewage and agricultural chemicals are poisoning the water.  Sediment is making the lake more shallow, breeding weeds and algae while killing fish.  Population growth and tourism add to the strain, while new fish species threaten the fragile ecosystem.

“It really is in alarming situation.  I fear if we don’t act with might and main now it won’t last long,” said U Than Htay, the park warden at the Inle Wetland Wildlife Sanctuary.

The crisis has led to an unprecedented effort by multiple government agencies to save the lake. The challenge, they say, is daunting. But it is the people who live on the lake who feel the damage most.

Daw Khin Mya, a 61-year-old retired teacher from nearby Heya-Ywama village, said the change in recent years has been dramatic.

“The whole village seems strange now compared to my childhood,” she said.

When she was young the water in front of her house was so deep she was afraid to swim in it. Now it’s so shallow that ever small boats can’t enter it in summer.

She recalls seeing fish swim in the glass-clear water around her home. Now, she said, the days when fish were cheap and abundant are gone.

“It’s been quite a long time since I last ate nga-phaing,” she said, referring to a native Inle fish that was once a staple for the Intha. Now they are hard to catch, and prices have shot up.

U Than Htay said the polluted water has become unliveable for some native fish. They also suffer from competition with exotic fish such as tilapia and African catfish, which have spilled into the lake from nearby fish farms during floods.

The tourist trade has also taken a toll. Silver and cloth-making shops dump acids and dyes in the water, while tourist boats spill oil and diesel.

But environmentalists say the biggest pollutants are pesticides and fertilisers from the floating tomato gardens scattered across the surface of the lake. The chemicals easily seep into the water.

Farmers used to rely on natural fertilisers but companies began promoting chemicals and their products are now widely used, said U Nay Aye, an assistant engineer with the Department of Irrigation.

U San Win, the headman of the Innchankela group of villages, the main tomato-growing area at Inle, said residents substituted local tomato seedlings with new ones from Thailand, due to their high yield and weather resistance.

“But for their growth, use of chemicals is essential, and they need more and more to sustain their good yield,” he said.

Innchankela is one of the fastest-growing villages on the lake, with a birth rate of eight a month. But they are not allowed to add more floating gardens, said U San Win.

“So we have to think of ways to boost our yield,” he said.

The population on the lake has jumped 20 per cent since 1983, according to Immigration and National Registration Department statistics.

Increased boat traffic, household waste, agriculture and cottage industries have “compounded the acceleration of environmental degradation”, according to a report by the department.

Not long ago, the lake was the sole source of drinking water for Inle’s residents. As pollution rises, they depend more on tube wells and bottled water. But many are still left without a safe supply.

U Than Htay said sewage is a major source of pollution, and as the population grows, the risk of water-borne disease is a major concern.

There are more than 20 villages on the lake, with many homes built on stilts above the water. Most dump their waste directly into the lake. Septic tanks cost as much as K1.5 million – too expensive for most locals to afford.

Tourism has provided jobs, but it also entrenched a local tradition where each village specialises in one craft, such as fishing, farming, weaving or metalwork. Conservationists say the practice leads to greater environmental damage.

But a bigger threat to long-term sustainability, they say, is the build-up of sediment on the bottom. This has made the lake shallower and changed the balance of minerals in the water – letting plants and algae thrive but hurting native fish.

U Than Htay said sediment has been increasing in the past decade, mainly due to slash-and-burn agriculture on the hills around Inle, which accelerates erosion into the lake. Locals say the build-up of sand and stones in the lake has destroyed some farms.

For the past three years, residents of the village of Thaleoo have had to dig out 100 boatloads of sediment from a nearby creek, said village headman U Tin Maung.

The digging is needed so that a royal raft carrying ancient Buddha images can pass along its usual route for the Phaung Daw Oo pagoda festival each October, he said.

“It’s a hard work, but if we don’t do the digging boats get stuck,” said his wife, Daw Win.

U Than Htay said sediment is starting to build up in the middle of the lake, overriding Inle’s ability to clean itself. Nine artificial lakes built a century ago to catch sediment are mostly full, he said.

Minerals from the sediment have dissolved in the lake, he said, hurting water quality while feeding the growth of weeds and algae.

Until about eight years ago, the lake bed was mostly clear of plants. Now weeds have choked the bottom and are shooting up to the surface.

Too many plants reduce the amount of oxygen in the water, making it difficult for fish and other organisms to survive, he said.

The Department of Irrigation has been trying to clear out the weeds on the main waterways, but it is an uphill battle.

“About three weeks later, they grow the same again,” said U Nay Aye, the department’s assistant engineer.

The weeds have now spread across the entire lake, he said – probably due to overuse of fertilisers on floating farms.

Local residents are beginning to realise the danger posed to their homeland.

“Our mother [Inle] has given us many resources so that we can live well. . . . Now she is old and wearing out,” said a concerned Intha who is active in the conservation movement.

“It is a delicate time to realise that our turn has come to take good care of her.”