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UBC Theses and Dissertations

What has Canada caught, and how much is left? Reconstructing and assessing fisheries in three oceans Schijns, Rebecca


Canada’s marine fisheries occur in three oceans, designated by Pacific, Arctic and Atlantic Exclusive Economic Zones (EEZs), where management bodies utilize catch records in order to make decisions regarding the future of their fisheries. However, current catch reporting systems and stock assessment processes are flawed, as catch records are missing key fishery components and assessments may use time series that do not represent the full scale of change. These shortcomings can directly impact the perception of healthy fisheries and influence future management decisions. This research provides a comprehensive catch record for all available marine populations in Canada’s three surrounding EEZs from 1950-2017 in order to estimate their current status and provide reference points that may be useful for managers to secure marine resources for the future. Catch reconstructions initially done by the Sea Around Us group and external collaborators, are refined and updated to 2017. Using reconstructed time series, the most recent ‘CMSY’ stock assessment method allows reference points to be estimated and reveals that the majority of Canadian fisheries need rebuilding. As well, ‘CMSY’ analyses are used to investigate shifting baseline effects on selected official stock assessments that exhibit shortened catch time series. Overall, this research contributes to improving scientific baselines in order to gain a better understanding of Canadian fisheries from a historical and managerial perspective.

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