I'm not aware of any character named Ishmael in the movie. Though other biblical names are used, Mat, Ben, etc. And some of the dialogue sounds suspiciously like blank verse.
"Are you going to eat that?" (Is anyone eating that?) was in the movie; but is not the answer.
"Pass the ketchup!" (Anyone got any ketchup?) was "Attack of the Killer Tomatoes," not "Jaws." Though the Jaws theme was used in one sickly funny scene.
The answer may be so obscure that it requires another hint: Song.
By the way, the special edition DVD set is well worth having. Some of the deleted scenes
showed Quint in a light missing from the theatrical release. "I recomend it to your attention" as the old Wiedemann's commercial said.
Chapter XL: Midnight, Forecastle. You got it, KJ. "Farewell and Adieu"
But the words were changed slightly for the movie and I can find no other reference to such a seasong, except in MB and Jaws. That probably means I haven't worked too hard at finding it.
One of the things I liked about the movie was the interplay of music and the plot. It was almost operatic. My very favorite example of this is the scene wherein Quint realizes the Orca is lost and it's now an endgame.
He walks into the cabin, glances up at the lifejackets--after declaring he'll never wear one again--as a flute reproses the tune and juxtaposes it with the shark theme on basses and cellos. It's as if the music mocks him. A brilliant production device on the part of Spielberg and Williams!
Quint is certainly "colorful."
"Front, Bow! Back, Stern! And if you don't get it right, squirt, I'l throw your @** out that little round window in the side. Hahahaha!"
"Back home, we got a taxidermy man. He gonna have a heart attack when he see what I brung in! Hahahaha!"