I recently read the book "Cinq siècles de pêche à la morue - Terre-Neuvas & Islandais" (Five centuries of cod fishing) written by Nelson Cazeils (in French, sorry!). The book discusses the history of cod fishing in all its aspects.
Bretons and Basques have been fishing and exploring the seawaters of Newfoundland and the Saint-Laurent before Samuel de Champlain and even before Jacques Cartier.