Amongst the various ailments plaguing Southeast Asia’s Mekong River, “hungry water” stands out with particular clarity. In recent dry seasons, the Mekong has in places turned a pristine blue as upstream dams rob it of the nutritious particles that normally color the river a healthy mud brown. It’s a phenomenon that could be highly destructive, with the sediment-starved water eating away at unbuffered river banks — hence the “hungry” epithet — and causing harmful erosion.
It also encapsulates the troubled state of the Mekong, a river which will look healthy on the surface but has grown increasingly sick from a wide selection of problems, including dam constructing, overfishing, deforestation, plastic pollution, and the insidious impacts of a changing climate. During El Niño-induced droughts in recent times, things got so bad that some people suggested the Mekong River was approaching an ecological tipping point beyond which it couldn’t get well.
But events previously yr suggest such doomsday predictions could also be premature, especially in Cambodia, which sits at the center of the Mekong basin. Because of the last monsoon season, which delivered above-average rainfall to the region, and authorities cracking down on illegal fishing, fish stocks have increased. Fishers along the Mekong have discovered giant fish thought to have disappeared, and the Cambodian government, which has a mixed environmental record, has stepped up conservation efforts.
“We’ve seen huge environmental pressures,” says a researcher. “And yet we also see the incredible resilience of this river.”
Amongst them is a latest government-backed proposal that seeks to show a very bio-rich stretch of the river in northern Cambodia right into a UNESCO World Heritage Site. Such a designation, reserved for sites of great scientific or cultural significance, means this a part of the river should, not less than on paper, enjoy protection from various types of development, including dam constructing. And so some conservationists at the moment are offering a more hopeful, if cautious, message: that with higher decision-making and management, the river may proceed to deliver the bounty of natural resources it has for millennia.
“The Mekong will not be dead,” says Sudeep Chandra, director of the Global Water Center on the University of Nevada, Reno, who leads the USAID-funded Wonders of the Mekong research project. “We’ve seen huge environmental pressures causing the Mekong to dry up and fisheries to almost collapse. And yet we also see the incredible resilience of this river within the face of those threats.”
Originating within the Tibetan highlands and winding its way through six countries before disgorging into the South China Sea, the two,700-mile-long Mekong River is home to the world’s largest inland fishery, with about 1,000 species of fish. Most of the 70 million people living within the basin depend on the river for his or her livelihoods, whether that’s farming, fishing, or other occupations. “A case could possibly be made that the Mekong is the world’s most significant river,” says Chandra.
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The river’s extraordinary productivity is linked to a large flood pulse that, within the wet season, can raise water levels 40 feet. With the rise comes sediment that’s essential to agriculture in addition to vast numbers of young fish, that are swept into Cambodia’s vital Tonle Sap Lake and other floodplains where they feed and grow.
However the river’s natural flow regime has been increasingly disrupted by dams, especially those who China began constructing within the early Nineteen Nineties within the Upper Mekong and which the country has operated with little regard for downstream impacts. A subsequent frenzy of dam constructing in Laos and elsewhere, totally on tributaries to the Mekong, has greatly exacerbated the issue, with dams blocking fish from completing their natural migrations. Already under extreme pressure from overfishing, some fish populations have plummeted, especially large species just like the critically endangered Mekong giant catfish, which may grow to 10 feet in length and greater than 600 kilos, but is now on the point of extinction.
With climate change intensifying, monsoon rains have develop into more unpredictable. During droughts in 2019 and 2020, the flow of water from the Mekong into Tonle Sap, the biggest lake in Southeast Asia, dried up, and dam operators made matters worse by holding back much of their impounded water for their very own economic gains. In consequence, mass deaths of fish attributable to shallow and oxygen-poor water were reported within the lake, and lots of the a whole bunch of 1000’s of fishers operating on the lake were forced to desert their work.
On the Tonle Sap River, which connects the Mekong and the lake, two thirds of the 60-something business “dai” operators working stationary nets, which in years past could each catch several tons of fish in only an hour, needed to shut down. “The situation became so dire there have been concerns these fisheries could not be sustained,” says Peng Bun Ngor, a fish ecologist and dean of the college of fisheries science at Cambodia’s Royal University of Agriculture in Phnom Penh. That might be a catastrophe for Cambodians, whose per capita fish consumption is higher than that of another people on the planet.
“Overall we’re seeing more fish being caught, with a greater diversity of species,” says an ecologist.
Nonetheless, the river system caught a break with essentially the most recent monsoon season, which runs roughly from June to November, delivering greater than average rainfall to the lower basin and the Tonle Sap Lake region. Although China continued to carry back water to counter its persisting drought, water levels in Tonle Sap rose multiple meter above recent-year averages. With the lake expanding into seasonally flooded forests, which offer excellent feeding grounds for fish, fish populations appear to have been boosted. “Overall we’re seeing more fish being caught, with a greater diversity of species and bigger sizes of individual fish,” says Ngor.
On a recent visit to the lake, Ngor noticed a rise in medium- and large-size carps, including Jullien’s golden carp, also generally known as the isok barb, a critically endangered species. There have been spottings of other rare fish too, just like the Laotian shad and clown featherback, together with increases of more common fish, just like the climbing perch and snakehead. Several wallagos, a catfish that may grow as much as 8 feet long, could possibly be seen jumping from the open water.
On the dai fishery, 13,000 metric tons of fish were caught last yr, up 30 percent from the yr before. “We’re seeing fish come back if conditions improve,” says Heng Kong, director of the Inland Fisheries Research and Development Institute of the Cambodian Fisheries Administration in Phnom Penh.
A 661-pound stingray caught within the Mekong River last June was the biggest freshwater fish ever recorded.
Chhut Chheana / Wonders of the Mekong
A crackdown by authorities on the usage of illegal fishing methods within the lake, similar to trawling and electrofishing, has also alleviated pressure on fish populations, experts say. The campaign followed a speech last yr by Cambodia’s long-serving Prime Minister, Hun Sen, by which he excoriated provincial officials for failing to tackle illegal fishing. However the crackdown has also come under strong criticism. Ostensibly targeted at larger-scale business fishers, it has resulted within the prosecution of small-scale fishers, especially those of Vietnamese origin, for minor infractions. Lots of these fishers, who’ve lived on and across the lake for a long time, have reportedly needed to flee.
Enforcement issues aside, conservationists worry that ecological improvements could possibly be temporary if more dams are built: the drive by Laos to rapidly expand its hydropower sector shows few signs of slowing down. Preliminary construction on a dam near Luang Prabang, on the important stem of the Mekong, is underway. Laos already has two dams on the Mekong itself.
Many hydropower projects, in Laos and elsewhere, are driven by political or private interests and infrequently have in mind environmental costs, observers say. One example is a small dam being planned in Laos near the Cambodian border, on the Sekong River, a vital Mekong tributary that has until now remained the one large free-flowing tributary within the basin.
Plans for 2 large dams along the Mekong mainstem appear to have been shelved, not less than for now.
Often known as Sekong A, the dam is being constructed by a state-owned Vietnamese company, however the project is shrouded in secrecy. No formal construction contract has been put in place. “It’s essentially being built illegally,” says Brian Eyler, who monitors dam developments within the Mekong as director of the Southeast Asia program on the Stimson Center in Washington, D.C.
While the dam is anticipated to provide only a tiny fraction of the region’s power supply, studies show it is going to have a robust negative impact on fish abundance and variety within the Sekong, in addition to alter water quality and further decrease the quantity of sediment and nutrients that reach the Mekong. “It’s an ideal example of a high-cost, low-benefit project,” says Eyler.
Cambodia, for its part, has begun to reconsider its own dam developments. A big dam it accomplished in 2019 on one other major Mekong tributary, the Sesan River, has proven a costly failure, with lower-than-expected energy production and disastrous environmental impacts. Plans for 2 large dams along the Mekong mainstem within the northern a part of the country appear to have been shelved, not less than for now. As an alternative, the federal government has proposed that the roughly 100-mile stretch of river where the dams could be built be designated a UNESCO World Heritage Site in recognition of its ecological importance and biological richness.
The Lower Sesan II dam on Cambodia’s Sesan River.
Chen Gang / Xinhua via Alamy Stock Photo
This section of the river, which flows leisurely past sandbanks and islands covered in seasonally flooded forest, has historically spawned as much as 200 billion fish every year, and its many deep pools, a few of which reach a depth of 260 feet, are believed to be refuges for huge fish, including the enormous freshwater stingray.
Last yr, fishers here caught a stingray weighing 661 kilos, which Guinness World Records verified as the biggest freshwater fish species ever recorded. The stingray was tagged and released by a team of U.S. and Cambodian scientists as a part of a first-ever regional telemetry study, which goals to learn more about fish movements and behavior.
The World Heritage Site proposal has also been described as a last-ditch effort to guard the Mekong’s remaining population of Irrawaddy River dolphins. While the last individual of a small dolphin group that lived on the Cambodia-Laos border died at the tip of last yr, a population of fewer than 100 individuals stays within the deep pools of Kampi, positioned toward the southern end of the river section proposed for defense. The pools are also a well-liked tourist destination.
Earlier this yr, fishers caught a large catfish weighing greater than 200 kilos within the Mekong River.
“The dolphins symbolize the biological importance of the Mekong River, and this designation would significantly attract the eye of all of the stakeholders concerned with protecting the Mekong River and its aquatic biodiversity,” says Somany Phay, a senior conservation officer with the World Wildlife Fund who also holds a senior position with the Cambodian Fisheries Administration.
There are signs that outreach efforts encouraging fishers to guard critically endangered fish are producing results. Earlier this yr, fishers caught a Mekong giant catfish weighing greater than 200 kilos within the Mekong River in Kang Meas district. Not one of the fishers within the group had ever seen such an enormous catfish before. But relatively than killing it and selling the meat for a sizeable profit, they decided to release it in a special ceremony, by which the fish was sprinkled with flowers and perfume before it was let go. “We knew this was a really special fish and it will be bad luck to kill it,” says one in all the fishers, Thou Theary.
Giant fish are sometimes considered good indicators of river health, so the capture of the adult giant catfish in Kang Meas sent a positive signal in regards to the Mekong’s future. “People have been saying that the Mekong is so degraded that it can’t be fixed, but this will not be true,” says Chea Seila, the Cambodian program manager for the Wonders of the Mekong project. “The Mekong River still flows, and the fish are still abundant.”
