Animal Treasure Island

Extremely well animated and generally well made 1971 movie by Toei. The bored and adventure-craving young (human) protagonist Jim and his talking mouse sidekick Glan are visited by a peg-legged cat pirate who is being pursued by a group of cloaked pig assassins. The feline promptly has them hold on to a mysterious casket as he attempts to take on his many assailants. After trying to evade the conflict unharmed, our two heroes return to the inn only to find out that the pirate is nowhere to be found. They decide to open the casket, which contains a map to the treasure of the infamous pirate Captain Flint.

Despite the fact that he wasn't the director, the movie features a lot of work from Hayao Miyazaki; he animated a very lengthy action scene and is credited as the "idea man":

looks like it's been remastered

I would watch that in a second. Great find!

It's not an anime, but there is an actual furry Treasure Island cartoon series... it has a weird mystical undertone and some episodes really left me wondering as a kid what the heck was going on (I suspect the writers were smoking a lot of weed ). It's hard to hunt down, only VHS rips exists.