Collapse of the Atlantic northwest cod fishery

In 1992 the Canadian Federal Minister of Fisheries and Oceans, John Crosbie, declared a moratorium on the Northern Cod fishery, which for the preceding 500 years had largely shaped the lives and communities of Canada's eastern coast. Fishing societies interplay with the resources which they depend on: fisheries transform the ecosystem, which pushes the fishery and society to adapt. In the summer of 1992, when the Northern Cod biomass fell to 1% of its earlier level, Canada's federal government saw that this relationship had been pushed to breaking point, and declared a moratorium, ending the region's 500-year run with the Northern Cod.

Observations on the reduced number and size of cod, and concerns of fishermen and amateur marine biologists was offered, but generally ignored in favour of the uncertain science and harmful federal policies of Canada's Department of Fisheries and Oceans until the undeniable complete collapse of the fishery. According to any reasonable analysis, the collapse was first due to massive overfishing. Second, the dependence for maintenance of the fishery itself on the nutrient cycle that was being disrupted by removal of megatons of biomass from a closed system resulted in the starvation of the residual fish. Academics have highlighted these following four contributing factors in the eventual collapse of the cod fishery.

A major factor that contributed to the depletion of the cod stocks off the shores of Newfoundland included the introduction and proliferation of equipment and technology that increased the volume of landed fish. For centuries local fishermen used technology that limited the volume of their catch, the area they fished, and let them target specific species and ages of fish. From the 1950s onwards, as was common in all industries at the time, new technology was introduced that allowed fishermen to trawl a larger area, fish to a deeper depth and for a longer time. By the 1960s, powerful trawlers equipped with radar, electronic navigation systems and sonar allowed crews to pursue fish with unparalleled success, and Canadian catches peaked in the late 1970s and early 1980s.

The new technologies adversely affected the northern cod population in two important ways: by increasing the area and depth that was fished, the cod were being depleted until the surviving fish could not replenish the stock lost each year; and secondly, the trawlers caught enormous amounts of non-commercial fish, which were economically unimportant but very important ecologically: incidental catch undermines the whole ecosystem, depleting stocks of important predator and prey species. With the northern cod, significant amounts of capelin – an important prey species for the cod – were caught as bycatch, further undermining the survival of the remaining cod stock.

...
Wikipedia