We certainly don't need to fear that dolphins could try to dominate or exterminate us. So why bother treating them in any special way? The reason for morale and ethics is to maintain society and minimize risk of revenge. In case of dolphins there's hardly a society, the risk of revenge is none. To keep natural balance we should restrain ourselves from killing them all off or domesticating all of them and that's it.

Maybe this is too brutal opinion for modern times but I think people have gone too far in their foolishness. We should remember our real place and our real power, so that we can learn to use it more responsibly, instead of playing silly Ramen (http://en.wikipedia.org/wiki/Concepts_in_the_Ender%27s_Game_...) games out of the boredom.