The marlin tries desperately to pull away. Santiago, no longer able to speak because he has become dehydrated, thinks, "You are killing me, fish... But you have a right to. Never have I seen a greater, or more beautiful, or a calmer or more noble thing than you, brother. Come on and kill me. I do not care who kills who" (92). This marlin continues to circle, coming closer and pulling out. At last it is next to the skiff, and Santiago drives his harpoon into the marlin's chest.
"Then the fish came alive, with his death in him, and rose high out of the water showing all his great length and width and all his power and his beauty" (94). It crashes into the sea, blinding Santiago with a shower of sea spray. With the glimpse of vision he had, Santiago saw the slain beast laying on its back, crimson blood disseminating into the azure water. Seeing his prize, Santiago says, "I am a tired old man. But I have killed this fish which is my brother and now I must do the slave work" (95).
Having killed the Marlin, Santiago lashes its body alongside his skiff. The fish is too heavy to put in the boat itself, so he must tow it back to shore alongside the boat. He pulls a line through the marlin's gills and out its mouth, keeping its head near the bow. "I want to see him, he thought, and to touch and to feel him. He is my fortune, he thought" (95). Having secured the marlin to the skiff, Santiago draws the sail and lets the trade wind push him toward the southwest.
An hour after Santiago killed the marlin, a mako shark appears. It had followed the trail of blood the slain marlin left in its wake. As the shark approaches the boat, Santiago prepares his harpoon, hoping to kill the shark before it tears apart the marlin. "The shark's head was out of water and his back was coming out and the old man could hear the noise of skin and flesh ripping on the big fish when he rammed the harpoon down onto the shark's head" (102). The dead shark slowly sinks into the deep ocean water.
The shark took forty pounds of flesh from the marlin and mutilated its perfect side. Santiago no longer likes to look at the fish; "when the fish had been hit it was as though he himself were hit" (103). He began to regret having caught the marlin at all, wishing that his adventure had been but a dream. Despite the challenges before him, though, Santiago concludes that "man is not made for defeat... A man can be destroyed but not defeated" (103).
Soon Santiago considers whether his killing the fish was a sin. He first says that he killed the marlin to feed himself and others, and if this is a sin, then everything is a sin. But he had not only killed the marlin for food, "you, [Santiago], killed him for pride and because you are a fisherman. You loved him when he was alive and you loved him after. If you love him, it is not a sin to kill him. Or is it more?" (105). Santiago soon ceases this line of thought to concentrate on getting back to shore.
He eats a bit of the fish from where the mako shark tore its flesh. He notes that it is delicious, quality meat, but knows that other sharks will smell it in the water. Two hours later, two shovel-nosed sharks arrive at the skiff. Since he has his harpoon to the mako, Santiago fastens his knife to the end of the oar and now wields this against the sharks. He kills the first shark easily by stabbing it in the eyes.
Santiago's final confrontation with the fish after he wakes further develops Santiago's equality with the fish and the operative conception of manhood which Santiago works to uphold. Pulling in the circling fish exhausts Santiago, and the exasperated old fisherman exclaims, "You are killing me, fish... But you have a right to. Never have I seen a greater, or more beautiful, or a calmer or more noble thing than you, brother. Come on and kill me. I do not care who kills who" (92). As before, the marlin is Santiago's exemplar of nobility. This, like so much of Santiago's relation to the fish, seems to recall an aristocratic code of honor in which dying by the hand of a noble opponent is as noble an end as defeating him.
Santiago's obsession with valorizing his opponent seems to be a far cry from our common idea that one must devalue or dehumanize that which we kill. To view a victim as an equal is supposed to render killing it a sin, and make oneself susceptible to death: the golden rule, if you don't want to die (and who does?), is to not kill others. Santiago defies this reasoning, though he accepts the consequences of its logic of equality. Instead of trying to degrade his object, he elevates it, accepting with it the equalizing proposition that his death is as worthy an outcome of the struggle as his opponent's death. He is only worthy to kill the opponent if he is worthy to he killed by him: two sides of the same coin.
Hemingway accentuates Santiago's personal destruction by reiterating his connection with the marlin he has caught. Soon after he has secured the marlin to the boat and hoisted his sail, he becomes somewhat delirious, questioning if it is he who is bringing in the marlin or vice versa. His language is very telling. "...[I]f the fish were in the skiff, with all dignity gone, there would be no question... But they were sailing together lashed side by side" (99). Even in death, then, the fish has not lost his dignity. This identification is highlighted after the first shark attack when Hemingway tells us that Santiago "did not like to look at the fish anymore since he had been mutilated. When the fish had been hit it was as though he himself were hit" (103).
The sharks are widely read as representations of literary critics, tearing apart the Santiago's (Hemingway's) catch (book). They can also be read as representations of the negative, destructive aspect of the sea and, more generally, human existence. As we have seen, the theme of unity is very important in the novel, but this unity does not only encompass friendly or innocuous aspects of the whole. While he battles against them, the sharks are no less creatures of the sea than the friendly porpoises Santiago encounters earlier in his expedition. This is brought out most strongly in the descriptions of the mako, the first shark Santiago encounters. "He was a very big Mako shark built to swim as fast as the fastest fish in the sea and everything about him was beautiful except his jaws. His back was as blue as the sword fish's and his belly was silver and his hide was smooth and handsome" (100). Indeed, "he was built as a sword fish except for his huge jaws" (100). The mako is not a nasty or brutish beast, but noble in its own way, a predatory marlin. Reflecting on his victory over the mako, Santiago says the shark is "cruel and able and strong and intelligent. But I was more intelligent than he was. Perhaps not... Perhaps I was only better armed" (103).
Santiago's discussion of sin is very significant in a novella about man's resistance against fate. He wonders if it was a sin for him to kill the marlin. "I suppose it was even though I did it to keep alive and feed many people. But then everything is a sin" (105). Santiago attempts to assuage this doubt by recalling that he was "born to be a fisherman as the fish was born to be a fish" (106). According to this reasoning, Santiago is fated to sin and, presumably, to suffer for it. This seems to express Hemingway's belief that human existence is characterized by constant suffering, not because of some avoidable transgression, but because that's just the way it is.
Thinking more, Santiago reasons that he did not only kill the marlin for food. Speaking to himself, he says, "You killed him for pride and because you are a fisherman. You loved him when he was alive and you loved him after. If you love him, it is not a sin to kill him. Or is it more?" (105). Adding to his guilt about killing the marlin, Santiago then recalls his enjoyment of killing the mako. As noted earlier, the mako is not a unconditionally wicked creature. As Santiago says to himself, "He lives on the live fish as you do. He is not a scavenger nor just a moving appetite as some sharks are. He is beautiful and noble and knows no fear of anything." Why then could he enjoy this killing and not the marlin's? Santiago offers two short responses, though neither one really answers the question: "I killed him in self-defense... And I killed him well" (107). The second response seems to more significant, but this would mean that killing the marlin was not a sin since he killed it well too. This suggests Santiago's sin, if it exists, must be interpreted differently.