Why does Santiago feel remorse for the killing of the marlin?

Santiago repeatedly apologizes to the marlin in a way that provides another way to read Santiago's sin. He says, "Half fish... Fish that you were. I am sorry that I went out so far. I ruined us both" (115). Santiago's transgression is no longer his killing of the fish, but going out too far in the ocean, "beyond all people in the world" (50). While the former sin helped account for the inescapable misery of the human condition, the latter focuses instead on avoidable misery brought about by intentional action. Santiago chose to go out so far; he did not need to do so, but in doing so he must surrender his prize, the marlin, to the jealous sea.