UBC Theses and Dissertations

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UBC Theses and Dissertations

Get it in gear : evaluating gear-based trade-offs in fisheries Cashion, Timothy Robert


Fishing gears’ damaging effects on the ecosystems in which they operate are a major environmental challenge of capture fisheries. The full cost of fisheries is currently not internalized into the economy, and thus to properly evaluate the benefits received from fisheries globally we must undertake a quantitative evaluation of the costs and benefits of including the ecosystem services upon which it relies. This thesis fills this gap through a full cost-benefit analysis of the world’s fishing fleets. First, I quantify the catches, discards and values of marine capture fisheries by gear type. Different gears disproportionately contribute to landings and landed value in comparison to their costs of discards and the potential shadow-value of these discards. Second, I propose a method to evaluate the short-term trade-offs necessary for fishing firms to maximize their revenues and profits. I find that through optimal management and rebuilding that fishers could increase their catches and profits in the selected case studies. Third, I evaluate whether current consumer-based sustainability initiatives are achieving ‘on-the-water’ effects. Here, I find that there is little reward for best-performing actors but a strong effect causing worst-performers to decrease their catches. Finally, I use the data on capture fisheries by gear type from earlier in the thesis to evaluate areas of low-cost conservation for species threatened by fishing gear. My results highlight areas of high conservation concern for particular fishing gears, and areas of high overlap between multiple fishing gear threats and multiple species of conservation concern. Taken together, this thesis advances our knowledge of impacts and trade-offs associated with different fishing gear types and improves our ability to restrict these impacts through management and market-based initiatives.

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