What moral theories are applicable to Life of Pi?

Morality is a system by which people determine right and wrong behavior. A moral theory explains why a certain behavior is right or wrong, and moral theories are absolutely applicable to the book Life of Pi. As a character, Pi even shows us which moral theories he does not adhere to. For example, Pi does not believe in moral subjectivism—that is, he doesn't believe that he is the ultimate authority on what is right and what is wrong—and that is indicated through how he tries to incorporate so many religious beliefs and behaviors into his life. This then describes Pi as a cultural relativist: right and wrong, for him, are determined by a specific set of cultural rules. The culture around him happens to be quite religious, so it is possible to discuss "Divine Command Theory," as it relates to morality and moral theory, as applicable to this story. This moral theory hinges on behavior being right or wrong according to the commands of a divine entity.
http://home.sandiego.edu/~baber/gender/MoralTheories.html