My rescue dog has an ear and a half. Does it mean something?

I've been told that they cut their ears to easily identify strays as being fixed. He also has the tattoo to mark him as fixed. It seems weird that he'd have both but you never know.

He's very sweet and friendly but definitely has some abuse in his history. Was somebody just mean to him?

I'm always being asked about it and usually just tell people that it was a shark attack (I adopted him during Shark Week) but it's there a real meaning behind it?