In "The Old Man and the Sea," the sea functions as a symbol of the entire natural world, isolation, loneliness and solitude. The sea is also a symbol for love, beauty, danger and cruelty. The sea is also a woman for the old man.
The old man chooses to work with "her" by reading the signs of the ocean in order to determine the best place to fish.
His relationship with the sea is founded in respect, whereas the other, younger fisherman in the story looks to conquer the sea. The sea symbolizes a more masculine entity for the younger fisherman. The difference in their relationships with the sea is exaggerated through their language. The old man refers to the sea by its feminine name "la mar," while the younger fisherman uses its masculine name "el mar."
The sea as a symbol of isolation and solitude is reinforced by the change in the narrating style the author uses when the old man is at sea. The narrator tells the story from a third-person perspective when the old man is on land, and then changes to reveal to the reader what the old man is thinking when he is out at sea.