The note to the song on Brenda Wooten and Robert Bartlett 'Starry-Gazey Pie: Songs of Cornwall' Sentinel LP SENS 1031 comments that 'it has been suggested that the song has its origins in an old sun-worship feast held on December 25th in which the cock is the sacred herald of the sun and the fish the emblem of fertility - Bawcock being a corruption of Le Beau Coq'. Perhaps to be taken with a grain of salt.

--Stewie.