The Old Man and The Sea - Symbolism in the Marlin

I know I already posted a little about symbolism, but I wanted to elaborate on that a little more than I did previously.  I only wanted to elaborate because I feel the need to emphasize the symbolism behind the marlin. I feel that the marlin could very well represent conflict and struggle in the old man's mind.  
First off, when the fish lurches forward, the old man's hand is cut open (Hemingway 30). The old man's job is already difficult as it was, the fish was only making it even worse.  This fish is obviously being used to accentuate the conflict and make the situation even more difficult.  
Another instance where the marlin worsens the struggle is when the old man is attempting to stop his hand from cramping up.  After he has been doing this for quite a while, the marlin leaps out of the sea (Hemingway 33).  The old man sees the fish for the very first time, yet he is already struggling to get his hand working again.  I think that the fish appears then because the old man is going through such a difficult time.  The fish symbolizes his challenge.  
As the giant marlin decides to start jumping out from the water, the fishing line is ripped from Santiago's hands so quickly that each of them are cut wide open (Hemingway 41). Now the left hand has been cut once, and the right hand has been cut twice, making the struggle even more difficult.  The conflict is now intensified due to the marlin, once again.  
The symbolism in the marlin is especially apparent when it starts to circle the boat.  Each time the fish takes a turn about the boat. the old man finds it harder and harder to stop himself from giving up (Hemingway 46).  He starts off strong, but at the fish continues to pass it becomes more difficult for the man to move on.  The symbolism is obvious here because the fish keeps the reader locked on the page as the suspense grows.  He represents the old man's struggle.  
In then end, the fish is only a skeleton, nothing but bones on  the beach.  He is no longer (Hemingway 59). To me, this represents Santiago letting go of this huge struggle and moving forward with his life.  

Hemingway, E. The Old Man and The Sea. New York, NY: Scribner, 1980