This paper explores, using an historical example, the challenges that small island economies face when they are heavily invested in one or two productive sectors, and where they have had privileged historical access to the resources that underpin those sectors, and suddenly that access is removed or reduced. The Islands of St. Pierre et Miquelon (SPM), a territory of France situated 25 km south of Newfoundland (Canada), were from the 1700s granted access rights to exploit cod fisheries and other species without much competition from European fleets. Later, only North American, Canadian, US, Greenland and SPM fleets were authorized by Canada to maintain a limited fishing effort after the implementation of the Canadian EEZ in 1977. French trawlers from the mainland were also excluded beginning in 1987 by Canada, increasing the incentives for fishermen from SPM to invest in the sector. SPM continued on that historical development trajectory of the cod industry, which became increasingly path dependent, with increased catch capacity and processing plants, further specializing and limiting alternative development that might have taken hold on the island. The economy of the Island was further pushed onto that path because of the exclusion of European fleets from Canada’s EEZ for the period from 1977-1992. However, the collapse of the northern cod stocks led to the cod fishing moratorium, imposed by Canada in 1992. This might argue for more concerted efforts over time at maintaining and enlarging economic diversification thus adding more resilience to these economies.