I'd say its a good theory. Mine would be injury from other pike and then infection. When CPR used to be loaded i caught pike with similar markings but larger as they were proportionally smaller. (make sence? maybe not) Anyway, i caught many with teeth marks from larger pike and some of the attacked pike weighed 10-12 pounds. I don't think it hurts the flesh but you should always cook pike fully anyway (tapeworms). I know theres another fungus pike get in those water bodies in the summer where they appear fuzzy. I'd never eat one but i believe they perish as you'll often see them washed up days later in same area. I think its due to the warm rich water.