A former fisherman who admits to having killed thousands of dolphins in Japan’s infamous dolphin hunt sat down with Australia's version of 60 Minutes to discuss why he is now trying to end the slaughter.

In an interview with reporter Liz Hayes, third-generation dolphin hunter Izumi Ishii describes how he grew up believing that killing and eating dolphins was something that everyone did. And although he says that he “felt really sorry for the dolphins,” Ishii began participating in the hunt when he was just a child -- killing countless dolphins over the course of his career.

Ishii says that years of hunting dolphins left him with feeling of sorrow and regret, so much so that in 1997 he quit the practice and cut ties with his colleagues. Now the former dolphin hunter has begun to campaign against the annual hunt, urging others throughout the world to write letters to the Japanese government asking that the hunt be banned.

“I have so far received nearly 900 letters,” says Ishii.“My plan is to take these letters to Japan’s Fisheries Ministry. I would like to get more and more voices so that the Fisheries Ministry cannot ignore voices gathering across the world.”