Personification is used by Hemingway to distinguish between the marlin and the mako sharks that tear it to pieces. Santiago regards the marlin as a noble and worthy opponent, an aristocrat of the sea. He sees his epic encounter with the marlin almost as a duel between two gentlemen. The mako sharks, on the other hand, are just vicious scavengers. There's nothing noble about Santiago's fight with them. This is a nasty, brutal slugfest, with no mercy given and none asked for.

Santiago has a bond with the great fish, an almost mystical connection which naturalizes the man as well as personifying the marlin. But it's not just the marlin to whom Santiago has such a deep connection; turtles, birds, and jellyfish are also his friends as he sails the ocean. It can be a hard and lonely life out there on the high seas, and so one can understand why Santiago gives personalities and thought processes to the animals he encounters on his numerous voyages. That way he's never truly alone.

In The Old Man and the Sea, Ernest Hemingway consistently uses personification to illustrate Santiago’s intimate bond with the natural world. More specifically, Hemingway supplies Santiago’s natural surroundings with human characteristics in order to highlight the respect that Santiago has for the awesome power of nature. As Santiago is out at sea, Hemingway writes:

“Just before it was dark, as they passed a great island of Sargasso weed that heaved and swung in the light sea as though the ocean were making love with something under a yellow blanket” (72).

The most striking instances of personification in the novella, however, occur when Hemingway describes the sea life that Santiago encounters. Hemingway imbues the fish, turtles, and other creatures with human characteristics. In one specific instance of this personification, Hemingway portrays porpoises as distinctly human:

“'They are good,' he said. 'They play and make jokes and love one another. They are our brothers like the flying fish'” (48).

This personification is all used to illustrate the brotherhood and kinship that Santiago feels with the natural world. He holds a deep and sincere relationship with nature that is striking.