Q: Do you believe there are more creatures in the 95% of the undiscovered part of the sea?

Look up the definition of "undiscovered". Nobody has any basis to believe there is or is not any such thing. You are talking about guessing. The best we can say is that television cameras dropped into the ocean near a California maritime museum have been revealing creatures never seen before every day. But nobody knows any such thing until they observe one. Science is based on observations, not guesses and polls.