The reader is introduced to the marlin because Santiago sees one of the projecting sticks dip in the water (B).
In <em>The Old Man and the Sea</em>, the main character becomes aware of the presence of the marlin when he realizes something is tugging at his hundred-fathom-deep fishing line. Because of the strength of the bite, the stick to which the line is attached is pulled into the water. Santiago immediately recognizes the fish as being a large marlin.
He was used to being made fun of.
We know this by him taking this reply in ‘with a sort of humble patience’. This means that he has experienced this kind of teasing - or even bullying before and he is used to it.
