Hemingway lived in Cuba and loved deep-sea fishing. He usually wrote in the morning and then went out on his power boat in the afternoon. He was getting old when he wrote "The Old Man and the Sea," and he was afraid that he might have written himself out. He was like the old fisherman, who hadn't been able to catch a big fish in a long time, in that Hemingway himself hadn't been able to get started on a new writing project for a long time. His best novels and most of his short stories were all behind him. He was drinking very heavily and suffering from depression. Fortunately for Hemingway, "The Old Man and the Sea" was a big success. Hemingway, being a fisherman, must have had many long spells during which he himself was unable to hook one of the big marlins which were the fish most sought after in the Caribbean. Hemingway prized courage and endurance, not unlike the old fisherman who refused to give up.
Thanks for the answer, but Is it only one autobiographical element ?