No, I wouldn't call a shark evil, but then they aren't highly organized creatures with the one single goal of eating humans.

Which brings up the question, what the hell do Wraith do other than eat humans? Seriously, I'm really curious. Do you think they do anything? Play cards? Talk to one another? Because you'd think that at their intelligence level, they'd have more of a purpose than merely surviving. Although maybe not, since apparently there's so many of them... maybe just surviving is difficult? hmmmmmm...