Mystery & Murder Riddles.

53: An Island.

Two best friends are stuck on an island for days. They have no food left and were starved for days.

Suddenly, a fisherman sees them,pulls his boat closer and talked to them. After much talking,he and one of the guys decided to go fishing to find something for them to eat.

After a couple of hours,only the fisherman returned with the salmon that he had prepared. He tells the guy that his best friend fell down from the boat and drowned before he could save him. Although the news was shocking and remorseful,due to his hunger,he ate the salmon.

After being rescued and he arrived home safely,the guy went to a diner and orders Salmon. Just after a bite,he pulls out his gun and shot himself right there.

Why did he commit suicide?