I'm currently unconvinced either way on this matter. However, enough arguments have been raised that I think this is worth the time of every reader to think a good deal about.
http://nothingismere.com/2014/11/12/inhuman-altruism-inferential-gap-or-motivational-gap/
Wouldn't that logic lead you to killing all predators or all prey depending on the answer to the question of whether the prey has lives not worth living? If "no", kill prey, if "yes", kill predators. In any case you're committed to a lot of killing.