Santiago hasn’t caught a fish in 84 days. ¬†He sets out alone and soon hooks a large marlin who drags the boat out to sea.
I wasn’t sure if Hemingway could keep me interested in two days at sea for 120 pages, but he did. ¬†At first, I thought this would be the traditional theme of Man Vs. Nature, but it ebbed and flowed with a lot of internal monologue and sometimes the fish was secondary to inner conflict of the fisherman.
I am not sure if I am stretching things to see a Christ-figure in the man.  He injures his hands and at one point Hemingway mentions he gives an involuntary noise like a noise one would make as a nail pierces his hand.  He spends two nights at sea which could be a parallel to the two night Christ spends in the grave.  At the end of the fishing trip, the man sleeps on his bed with his arms stretched out.
If I am way off base, let me know in the comments.