On the shimmering waters of Myanmar's Ayeyarwady River, fishermen tap a wooden stick against the side of a boat and sing out a rhythmic sound of "kroo kroo".
It's a call to summon their unlikely partners — Irrawaddy dolphins.
Together, they perform a delicate choreography.
The dolphins herd shoals of fish toward the fishermen's boat.
When the lead dolphin approaches, it signals by flapping its fin.
A fisherman throws the net, trapping fish between the approaching dolphin and the boat.
It's a win-win situation: The dolphins catch any escaping fish from the net, while the fishermen benefit from the fish driven toward their boat and catch more to sell at market.
"These dolphins take care of us and help meet our needs," 53-year-old fisherman U Kyi told the ABC.
"I feel a sense of pride in the close bond we share, like they're family."
This cooperative relationship between fishermen and dolphins in central Myanmar is as intricate as it is rare and has been passed down over generations.
"My first experience was when I joined my father on a fishing trip as a kid," said U Kyi.
"When there were no boats or other noise around, the dolphins would come to us right away."
But this ancient bond is under threat.
A historic bond in peril
Irrawaddy dolphins, charismatic and uniquely adapted to freshwater, are endangered.
Found only in a few rivers — Myanmar's Ayeyarwady, Cambodia's Mekong, and Indonesia's Mahakam River — their survival is threatened by harmful fishing practices and environmental degradation.
"Illegal fishing is a worsening problem," says Win Hte, a program officer for the Myanmar branch of the Swiss environmental NGO Helvetas.
Some fishermen use destructive methods that indiscriminately kill fish, like detonating dynamite sticks or electrifying waters with car batteries connected to rods or nets, known as "electro-fishing".
"A lot of fish go to waste — many sink to the bottom and only float up once they start to rot," U Kyi said.
Gill nets, toxic chemical use and increased boat traffic have further jeopardised the dolphins' survival.
According to a 2020 report by the Wildlife Conservation Society, 79 Irrawaddy dolphins remained in the Ayeyarwady River — a slight improvement from 69 in the previous year.
However, the situation has deteriorated since Myanmar's military overthrew Aung San Suu Kyi's democratically elected government in 2021, destabilising the nation and halting many government-backed conservation initiatives.
"After 2018, we started getting much more reliable data as experts brought their knowledge to Myanmar," Win Hte said.
"But now, it's nearly impossible."
The instability has driven many researchers away.
For three years, Win Hte has studied dolphin and porpoise populations at the river mouth of the Ayeyarwaddy in the Gulf of Mottama, but his monitoring has been increasingly hampered by the security situation.
"Tracking the exact population is now very challenging," he said.
The rise of 'Dolphin Guardians'
In the absence of formal conservation efforts, community-based conservation efforts have stepped up.
A group of local fishers, known as the "Dolphin Guardians", monitor dolphin populations and report illegal fishing.
The program involves about 75 fishers, including 15 women, across several communities.
Launched during the COVID-19 pandemic, it has helped fill the gap left by halted government monitoring.
"We educate people that the number of dolphins reflects the health of the river — they are interconnected," said U Kyi, who is a member of the group.
The guardians patrol the river, counting dolphins and keeping an eye out for illegal activities like electro-fishing.
However, the war has made river monitoring risky.
"There's ongoing conflict in our area, so we have to check with each other before heading out to the river to avoid trouble," says U Kyi.
Burma Dolphins, a social enterprise that supports the guardians, once offered alternative livelihood programs for fishing families to reduce pressure on fish populations but many of these programs have stalled.
The challenges of cracking down on illegal fishing
Illegal fishing practices, particularly electro-fishing, have devastated fish populations and harmed dolphins.
U Kyi has witnessed species like Gagata catfish decline from areas where he once fished.
He said confronting the illegal fishers was impossible.
"They have more people with dangerous equipment," he said.
Instead, he gathers information on their activities and reports it to the Burma Dolphins who map illegal fishing hotspots.
Although the monitoring was not perfect, it kept communities engaged in conservation, said network co-founder Paul Eshoo.
"We're just trying to do our part and keep our staff fed," Mr Eshoo said, referring to network members like U Kyi who are paid for their participation.
Hope through community efforts
Win Hte said community education, particularly for young people, was important despite the country's despite instability.
"We inform villages along the coast, and they also help us with information like if they find any [dolphins or porpoises] dead, so we can map the incidents," he says.
Before the military coup, conservation initiatives showed promise.
Protected zones were established along the Ayeyarwady, and eco-tourism allowed tourists to watch a dolphin-fisher cooperative for a fee, generating a significant income and awareness.
More women were becoming involved too.
With such programs on hold, grassroots efforts like the Dolphin Guardians' community monitoring provide a glimmer of hope.
"These dolphins have taken care of us and taught us so much," U Kyi said.
"When I see dolphins while fishing, it feels like meeting a relative," he added.
