After three days and two uncomfortable nights on the Irrawaddy River in Myanmar, it was starting to feel like we weren't going to find the dolphins.
Each morning since leaving Mandalay, a team of three researchers had taken up their positions at the front of the boat.
With binoculars glued to their eyes, they'd scoured the shallow waters. Wind conditions and GPS readings were carefully noted, but the column titled Dolphin Sighted remained defiantly blank.
We had hitched a ride aboard a research boat run by the Department of Fisheries in Myanmar (also known as Burma). A creaking wooden vessel with a dodgy engine, it is the front line for Burmese efforts to save the Irrawaddy dolphin.
There are larger numbers of the dolphin in both India and Bangladesh but in the Irrawaddy river, just 63 are thought to be left. That makes this population critically endangered, one step away from extinction.
Just as we were beginning to lose hope, a telephone call came through from villagers further upstream. A pod of dolphins had been sighted. We were soon in a small boat heading into one of the river's many narrow channels.
The dolphins in the Irrawaddy are special because - as long as anyone can remember - they've fished co-operatively with the local villagers, chasing shoals of fish towards waiting nets. The officials with us are understandably keen for us to see this in action, so we stop at a village and join up with some local fishermen.
Once we're within range, the fishermen get to work and begin to try to communicate with the dolphins. That means splashing loudly with an oar in the water and tapping a stick repeatedly on the side of the boat.
Soon there are four or five dolphins 10m away from us. The water is murky so we only see them briefly each time they surface for air.
They are interested for sure, but it's hard to know if they are really up for fishing.
Our fishermen cast their nets several times, but pull them up empty.
After a couple of hours of splashing, tapping and empty nets the dolphins have had enough and swim off. The fishermen put their equipment away and sheepishly give us their excuses.
"There aren't many fish here," one says. "It's dolphin mating season," says another, "they're distracted."
Then a man called Aung Thin speaks up, with a clarity that cuts through the chatter.
"We used to be like a family with the dolphins," he says. "When we make the tapping sound the dolphins used to come to us. Now they don't come close because they're scared of being trapped by the electric shock fishermen who make the same tapping sound."
The other fishermen nod in agreement. Things have changed.
The rise of electric shock fishing means an age-old bond of trust between man and dolphin has been broken. The dolphins are now wisely keeping their distance, unsure as to whether man is a friend or foe.
Back on board the boat, one of the researchers shows some gory pictures of dead dolphins in varying state of decay.
"There are three reasons why dolphins die here - ageing, electric shock or being trapped in a fishing net," Kyaw Hla Thein from Myanmar's Wildlife Conservation Society says.
"But these dolphins are only one year old - so it's not age - and there are no injuries from a net - so obviously the cause of death is electric shocks."
Electric shock fishing is not new on the Irrawaddy. For more than a decade fishermen have been wiring car batteries up to bamboo poles, electrocuting everything within range.
What's different now is the scale, says Han Win from the Department of Fisheries.
"Now they're using bigger batteries and better equipment and transformers from China to boost the voltage," he says.
"They work in big groups and when we patrol there's just five of us - so we're outnumbered and have no chance to arrest them."
That night we moor up and go with the government officials into a village known to be home to several electric shock fishermen. There will be no arrests, this is part of an outreach programme, educating people about the threat their fishing techniques poses to dolphins.
Several hundred villagers sit down and then watch as a Japanese documentary on the Irrawaddy dolphins is projected onto a screen. It's a mystifying experience.
Burmese ministry budgets have not stretched to a translation, so we watch the pictures of the dolphins and while listening, befuddled, to the Japanese commentary. There's a loud cheer whenever a fragment of Burmese can be heard and understood.
When the documentary has given way to a (much more popular) Burmese soap opera we chat with some of the villagers.
Everyone has seen the electric shock fishermen at work. Some like farmer Aung Khin even admit to having some sympathy for them.
"They use that technique because life is getting difficult now," he says. "We didn't see it when I was young - but in recent years there's no doubt that electric shock fishing is getting more and more popular."
For now the number of dolphins being killed seems to be offset by new births. It's thought that in the last 10 years the population has remained fragile but stable at about 60.
From what we witnessed what appears to have been lost, possibly for ever, is trust, and a special relationship between man and mammal.