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A staple's physical properties set the organization of the economy built around it. For cod these were perishability, dependence on salt, seasonal runs, and dispersal along thousands of miles of coast. Trace what those properties demand in capital, labor, shipping and land, and you can predict the settlement patterns, credit systems and political conflicts that follow.
France had abundant cheap salt, so its fishermen could heavily salt a 'green' cure aboard ship on the offshore banks. England lacked cheap salt, so it lightly salted the fish and dried it on land. That forced the English to occupy harbors and beaches in Newfoundland. A difference in curing technique became a difference in territorial presence and, eventually, sovereign claims.
West Country merchants ran a seasonal migratory fishery from England. They saw permanent residents as rivals for the best shore space and as a drain on the seamen who returned home each year. They lobbied to discourage settlement and to govern the island through 'fishing admirals.' As a result, Newfoundland's resident population, local government and agriculture developed long after those of other colonies.
New England sold its best cod to Catholic Europe and its refuse grades to feed slaves in the West Indies. It took sugar and molasses in return, including from foreign islands. This built an independent shipping and merchant class whose commerce collided with mercantilist restrictions such as the Molasses and Sugar Acts. The fishery's trade network therefore gave New England both the means and the motive to break from the empire.
European states valued the distant-water fishery for its fish and also as a training ground for sailors who could be pressed into naval service in wartime. This strategic rationale justified subsidies, bounties and fierce treaty bargaining over fishing rights. It also explains why powers fought to keep access to fisheries they could have bought fish from more cheaply.
The cod fishery needed little capital and could be run by small independent boats from many scattered harbors. It therefore resisted centralized monopoly control, unlike continental staples. That dispersal encouraged local commercial autonomy and competing regional interests. It helps explain why Newfoundland, the Maritimes and New England drifted apart politically instead of consolidating under one authority.