The cod fishery was the major employment in Newfoundland - a province that is the poorest (I'm pretty sure) in Canada. Over a short period of time it grew radically in size. What else was there to do? Economically, there was very little of anything other than fishing. There have been numerous spectacular failures at bringing industry to the "rock". The closure, or even curtailing of the cod fishery would cause major economic hardship to an already poverty stricken province. Cod was a way of life, and had been for 100's of years. There was a saying in Newfoundland - to the effect that no matter how bad times came, you could always fish. The premier of Newfoundland who brought it into confederation was known as the Cod Father. Politically, cutting back on cod fishing was seen to be suicide, and probably with good reason.
The politicians would cherry pick science in order to keep fishing quotas as high as possible. There was talk of the damage scientists were going to do to Newfoundland. Uncertainty levels were used in ways to maximise the estimates of Cod Stocks, and the resulting size of fish quotas. The result was that cod fishing has been more or less banned - for I don't know - a decade? in a classic case of locking the barn door after the horses escape. The cod still has not recovered.
aspiring to genteel poverty