The two pieces of evidence that show Harborough considers the shark as belonging in the ocean are:
C. “The shark was not passive, in the element, as I was; it was monarch of the waves, it could drive through them with the precision of a torpedo.”
E. “I had invaded a realm which I had no business to invade ... and its guardian was come to punish me.”
These selections illustrate the shark's dominance in its natural habitat (the ocean) and convey the idea that the ocean is the shark's rightful realm, which Harborough acknowledges he has intruded upon.