Less than a year before the next Summer Olympics will be held in Tokyo, a cetacean-advocacy group is once again drawing attention to Japan's horrific dolphin slaughter.

Ric O'Barry's Dolphin Project has released the first-ever drone footage of the annual kill in the Japanese town of Taiji.

The dolphins are driven into a cove 150 kilometres south of Osaka, where more than 2,000 are slaughtered or killed.

O'Barry, a former dolphin trainer, has dedicated his life to fighting the captivity of these creatures.

This came after he concluded that a dolphin named Kathy, who performed on the 1960s-era Flipper TV show, committed suicide in his arms by refusing to breathe.

https://twitter.com/Dolphin_Project/status/1192096739374878720

This ecological tragedy in Taiji was brought to the big screen in the unforgettable Oscar-winning documentary The Cove in 2009.

Director Louis Psihoyos relied on B.C. free diver Mandy-Rae Cruickshank to place underwater camera to record the killing.

But even that wasn't enough to persuade Japanese authorities to put an end to the carnage.