You definitely can! They have a defense level of 30 and a defense bonus of 0 (nothing) against a ranged attack. This makes it some of the very best ranged exp on a slayer task when using a cannon. The only combat style that they are weaker to than range is magic, but there is no real spell that is strong enough to effectively kill them if you can only attack 1 or 2 at once. Melee works just as well as ranged against Bloodvelds. So in the end you can pick whatever skill you prefer, or want to train when fighting them.