The rock icon made the statement in a recent Instagram post.
He shared an image of himself wearing a T-shirt saying 'please stop killing whales', and accompanied it with a caption talking about what he described as the 'magnificent giants'.
'F*cking up the planet'
"Just the fact that this T-shirt has to get printed blows my mind. I remember the save the whales campaign from the 1970s," Adams wrote.
"Even after years of people campaigning to stop whaling, there are still countries that persist like Japan, St Vincent/Bequia, the Faroe Islands and Norway that consider it acceptable to kill these magnificent giants.
"There's no need for it, despite any cultural or aboriginal claims of sustainability. The future is recognizing that killing animals for food is fucking up the planet."
Adams, a longtime vegan advocate, has previously spoken out about the benefits of a plant-based diet for human health, the environment, and for animals.
"Being sympathetic to animal rights is just something that came very naturally to me," he once told vegan charity PETA. "Perhaps because I used to have dogs growing up, and you know they became part of the family. And it never occurred to me growing up. I never put the whole thing of animal cruelty and that together as a youngster.
"But the moment I began to understand what was going on with the treatment of animals, it led me more and more in the way of the path I am [on] now, which is a complete vegan."