Blood flowed from beneath a shoreside tent as dolphins were killed at Taiji, Japan, on Tuesday.

The waters made famous by the Oscar winning documentary The Cove ran red in the killings by local fishermen, who worked for four days on a herd of 250 bottlenose dolphins held in nets.

Activist Melissa Sehgal, of Sea Shepherd's Cove Guardians, said in a livestream from the scene that 52 of the dolphins were separated to be trained for marine park work, but many of the remaining dolphins were killed for their meat.

Ms Sehgal described the scene as dozens of dolphins were herded or dragged into the tent, later to emerge stacked on skiffs for transfer to the town's butcher house.