The terrified animals are then left overnight trapped in the tiny inlet. The fishermen claim this makes the dolphins' flesh softer, sweeter, tastier.
At dawn the next morning, traders arrive from all over the world to buy dolphins they can train for aquaria. A particularly cute creature can fetch 100,000.
But once the buyers have chosen their specimens, the rest are slaughtered. The fishermen begin slashing at the animals with gutting knives and impale them with sharpened poles.
The terrified animals thrash around in the water - turning it a bright frothy red. Agonised sounds fill the air as mother dolphins call out to their young and try desperately to protect them.
When the petrified animals have been weakened by blood-loss and pain, they are hauled aboard the fishing boats. Here, the 'lucky' ones have their throats cut. Others have their spinal cords slashed open to paralyse them. Many more are simply left to drown.
Such horrific scenes are seen every few days during the six-month dolphinhunting season, according to Ric O'Barry, head of the international Save Japan Dolphins Coalition and trainer of Flipper, star of the Seventies TV series.
'Every year, the fishermen try to provoke us so that the government has an excuse to deport us,' he says. 'They will often torture animals in front of us. A few years ago, one fisherman held up a baby dolphin in front of my face and sliced its head off.'
Other witnesses to the slaughter describe equally horrific scenes. Mandy-Rae Cruikshank, seven times world free-diving champion, saw the cull two years ago while making a documentary. She was stunned by the brutality she witnessed when a pod of 40 dolphins was herded into the Taiji killing cove.
'They separated the babies - some were only as big as my arm - and then they began to kill them,' says Ms Cruikshank. 'The emerald water in front of us began to turn red.
'One dolphin had been stabbed and tried to escape the killing cove by leaping over two nets. Blood was streaming from it. We saw its final breaths - it was impossible not to cry.'
Then something even more barbaric occurred. Ms Cruikshank was forced to watch helplessly as the fishermen turned their attention to the young dolphins.
'The babies were led out to sea and were either killed or left to die of starvation,' she says. 'It was awful to watch. Awful.'
In The Cove, a documentary about the cull to be released in UK cinemas next month, Ms Cruikshank tells of the countless times that dolphins have rescued drowning sailors and surfers. They are the only creatures who regularly risk their own lives to save humans from certain death.
One celebrated case involved the rescue of surfer Todd Endris in Monterey Bay, California, in 2007. A 15ft Great White shark attacked him, ripping the skin off his back 'like a banana peel', he said.
The shark then attacked again, swallowing his right leg and trying to wrench it off. Only his surfboard, which had become sandwiched between his thigh and the shark's lower teeth, prevented the loss of his leg.
But as the shark moved in to deliver thecoup de grace,a miracle happened. A pod of dolphins surrounded Todd and attacked the shark. Within moments, the shark was beaten back and swam away. The dolphins stayed with him until he was able to re-mount his surfboard and struggle ashore.