G'day Noreen, petem et al,
Ewan MacColl and Peggy Seeger interviewed a lot of fishermen for the BBC Radio ballad Singing the Fishing - particularly old Sam Larner, of Winterton. The song Shoals of Herring came very directly from Sam's own words and lifetime fishing.
I remember Ewan & Peggy saying that, when they took the song back and sang it to Sam, he declared; "Why, I've known that song all my life!" I would hope that means that they really caught the sound and fact of Sam's experience.