(Orcaella brevirostris) remain in the Mekong River's Cheuteal trans-boundary pool, which separates southern Laos from northern Cambodia. That number is down from six just a few months ago, and the drop was unexpected.
Unlike many freshwater animals, Irrawaddy dolphins can live in both salt and sweet water, but groups rarely move between the two. Only the freshwater populations are considered critically endangered, and barring the Mekong River, the animals exist in just two other localities: the Ayeyarwady River (Myanmar) and the Mahakam River (Indonesian Borneo).
"The alarming decline of Mekong Irrawaddy dolphins in Laos that we have witnessed this year is tragic," says Teak Seng, Conservation Director for the Greater Mekong region. "At this stage, we fear that in a year or two, there may be no more dolphins in Laos." Irrawaddy females give birth only every two to three years, and just 0.8% of calves survive to adulthood. All things considered, there is little chance of reversing the situation in Laos.
A previous survey, which wrapped up in 2015, provided a glimmer of hope when it showed that the dolphins' rate of decline had slowed substantially – so what went wrong this year? The team suspects an upsurge in gill-net fishing is to blame: the curtain-like argyle nets have long been known to snag dolphins as they move in and out of deep water.
"The use of gill nets in the Mekong River is prohibited in Cambodia – where there are an estimated 80 dolphins – but not in Laos," says WWF. "Only the actual deep pool where the dolphins are is protected." In fact, the nets are often draped bank-to-bank in local waters – including in the section of river directly outside the trans-boundary pool.
The survey team has called for an immediate ban on gill-net use within two kilometres (1.24 miles) of the pool to protect its last dolphin survivors, but whether that appeal succeeds remains to be seen. Like many other conservation challenges in poverty-stricken regions, the situation in Laos is about balancing species-saving efforts with the needs of local communities.
Fish contribute some 61 percent of the protein intake in Laos – Southeast Asia's poorest state – and it's estimated that 71 percent of the fishermen who supply that high demand use gill nets. But while modifying such harmful fishing practices seems like an obvious and urgently needed step to save the area's dolphins, a strict ban could affect the livelihoods of thousands of local families. This human-wildlife conflict has been WWF's biggest campaign hurdle. Success in neighbouring Cambodia, however, suggests that working with, rather than against, the fishing community is key.
A small initiative in the Sekong River basin, a Lao tributary of the Mekong, also supports this approach. In collaboration with WWF, a team of educators from Conservation International helped usher in a programme that allowed local fishing communities to play an integral role in conservation. Proper management, the project hoped to show, would actually benefit fisheries because a healthy, balanced ecosystem boosts fish production and species diversity. Conservation zones were set up for 24 villages along a 500-kilometre (310 mile) stretch of river, with community members elected to protect them. After the initial test period, 75 percent of those communities reported better catch rates.
"The loss of [the Irrawaddy dolphin] for Laos is even more tragic given that it was entirely preventable through strict enforcement against gill-net fishing," adds Seng, noting that the time to act is now.
Entanglement in fishing gear isn't the only threat these dolphins will face in the coming years: despite the objections of Thailand, Cambodia and Vietnam, construction plans continue for the Don Sahong hydropower dam. The dam site is less than two kilometres upstream from the trans-boundary pool – and this is just one of 11 proposed dams along the river. The structures threaten to block the only year-round migratory channel for fish and dolphins in the Mekong.
A rerouting of local fish populations could also spell trouble for inland fisheries, and the extent of that impact is difficult to predict. Some research suggests entire portions of the lower Mekong could be transformed into sterile zones. "If the measures don't work well, it will be too late to undo the damage," University of Wisconsin-Madison professor Ian Baird, who studies Mekong fisheries, told AP.
Top header image: WWF Cambodia