CHHNOK TROU, Cambodia — Flashing a broad,
toothless grin, Loeng Yang Boi gazes out from the boat that has been
his home for the last 40 years and indulges in the familiar daydream of
the fisher.

“It was this big,” the 71-year-old said, his dark eyes lighting up and
leathery arms stretching out to indicate the size of the giant catfish
he once caught as a young man. “But that was over 30 years ago, even
before the Khmer Rouge came,” he said, recalling the glory days of
Cambodia’s Tonle Sap, southeast Asia’s biggest lake whose bountiful
waters, ebbing and flowing with the seasons, support some 1.2 million
fishers.

“Now, the fish I catch are getting smaller and smaller. There are so
many fishermen they catch fish faster than they breed,” he said,
pointing to the hundreds of little houseboats that make up this
bustling floating village.

For thousands of years, the chocolate brown waters of the Tonle Sap,
rising and falling in a unique annual cycle, have supported countless
generations of fishers, bringing fame and fortune to this small
southeast Asian nation. Legend has it the stunning temple complexes of
Angkor, built by the mighty Khmer civilization which ruled supreme in
Indochina 1,000 years ago, were built on wealth netted from the lake.

Today, Cambodia, an impoverished international minnow of just 13
million people, lands more than 400,000 tons of freshwater fish a year,
ranking it only behind China, India, and Bangladesh. Some two-thirds of
this comes from the Tonle Sap, providing vital income and food for a
nation slowly emerging from three decades of war.

DAM IT

For all the familiar doom and gloom of the fishers, scientists fear the
future of the lake, and in particular the annual floods so crucial to
its fisheries, could be at risk.

Every spring, as glacial melt-waters from China and Tibet flow down the
Mekong, the lake swells to five times its dry season size, covering
some 5,800 square miles — nearly as big as Lake Ontario in North
America. Come November’s dry season, the level of the mighty river
falls back down and the lake slowly drains away again. Fish follow
these “floods of fortune,” as locals call them, in their billions to
feed in the rich waters of the mangrove swamps and inundated woodlands
around the lake’s shores.

But experts who have studied old Mekong records from Laos — Cambodia’s
data was destroyed by the Khmer Rouge — are worried the ever-growing
number of dams in the river’s upper reaches are smoothing out the
annual ebb and flow and reducing the floods.

“Not only are dams decreasing the water flow, they also cut off access
for fish larvae to their spawning areas,” said Nicolaas van Zalinge, a
Mekong River Commission biologist who says the river level has dropped
some 12 percent since the 1960s.

In China, one huge dam, soon to be joined by a second, already spans
the Mekong. And some 25,000 other minor irrigation projects, many of
them built with U.S. aid in northeast Thailand during the Vietnam war,
are dotted throughout its watershed. With more massive projects planned
for coming years — including a cross-Mekong dam at Sambo in central
Cambodia — van Zalinge urges politicians to pause for reflection.

“For a long time there has been a push for the building of dams and
irrigation systems driven by the big banks,” van Zalinge said.
“Governments must consider their effects when investing in irrigation
and other schemes.”

FISH OR RICE?

Van Zalinge believes the lake’s fisheries are sustainable at current
levels of flooding and fishing — but only if the delicate ecosystem is
protected from a host of other threats. With the increased destruction
of ancient rainforest across the region and the consequent rise in
erosion, it is debatable whether the lake will be there at all in the
long term, or whether it will have completely silted up.

“The level of siltation is very minimal. but we should be concerned
about the amount of deforestation upstream and around the lake,” said
Nao Thuok, director general of Cambodia’s Department of Fisheries.
“Maybe in 100 years’ time there will be one very shallow or two
separate lakes,” he said.

Doomsday predictions of the Tonle Sap disappearing within the next few
decades are looking unlikely, but the Cambodian government and Asian
Development Bank are sufficiently concerned to be investigating
projects to reduce the effects of siltation.

Fishers are also being urged to do their bit by using larger mesh nets
to allow young fish to escape and go off to breed and by stopping the
clearing of mangrove swamps around the lake to make way for new rice
fields in the dry season.

“One of my main concerns is the rampant clearing of the floodwater
forests around the lake, which are the vital habitat of the fish,” Nao
Thuok said.

But for all the strong words, a lack of environmental education for
fisheries officials combined with Cambodia’s notoriously lax law
enforcement does not suggest change will take place overnight.

Meanwhile, far away from the scientists’ bar charts and satellite maps,
the fishers themselves are beginning to contemplate the beginning of
the end of an ancient way of life.

“Nine years ago, all this used to be mangroves,” said Ngyen Yang Chou,
58, with a broad sweep of his arm across the waves which have served as
home to generations of his forebears. “But it’s all been cleared to
make way for rice fields. I think maybe I will look into farming and
send my children to the village. It is too difficult to make a living
on the water.”