More than 1400 dolphins were killed on Sunday off the coast of the Faroe Islands in a single day, the Sea Shepherd Conservation Society said, as part of the Danish territory's century-old traditional Grindadrap hunt.
The US-based NGO said the slaughter of 1428 Atlantic white-sided dolphins is considered to be the largest single hunt of cetaceans ever recorded worldwide.
The annual dolphin drive, when several hundred pilot whales are slaughtered for their meat and blubber, is part of a 1000-year-old tradition in the North Atlantic archipelago.
The dolphins are herded towards land by motorboats, before being killed by whalers on the shore.
Images of local residents slashing dolphins, turning the water red with blood, have fuelled protests from environmental activists who say the hunt is cruel.
But this year the number of mammals slaughtered prompted an outcry from animal rights groups for the excessive killing, producing "more dolphin meat from this hunt than anyone wants to take", Sea Shepherd said in a press release.
Faroe Islanders fight to preserve their tradition of killing cetaceans, which sustains a key part of their diet.