Economic Impacts of Ocean Deoxygenation on Marine Fisheries and Ecosystems
Date: July 29, 2025
Time: 9:00 am
Location: via Zoom (link TBA)
ABSTRACT
Ocean deoxygenation, characterized by declining oxygen content in marine waters, represents a major threat to global fisheries and marine ecosystems. This dissertation examines the ecological and economic impacts of deoxygenation on fish populations and fisheries through an integrated interdisciplinary approach. The research combines oceanographic, biological, and economic perspectives to quantify these impacts at different spatial scales. First, I establish the fundamental relationship between deoxygenation and marine ecosystem changes, discussing how oxygen depletion affects fish physiology, habitat distribution, and food web dynamics. Through literature review, I identify key mechanisms linking biogeochemical processes to fisheries outcomes, including direct effects on fish growth, mortality, and reproduction, as well as indirect effects through habitat compression and predator-prey relationships. The dissertation employs innovative methodological approaches, including the Aerobic Growth Index to assess species vulnerability to deoxygenation, and ecosystem modeling using Ecopath with Ecosim to simulate future scenarios. Case studies of Pacific halibut and the East China Sea fisheries reveal significant potential impacts, with biomass reductions of up to 89% and corresponding total economic losses exceeding ~$200 million projected by 2100 under high-emission scenarios. The research demonstrates that impacts vary across species, fishing fleets, and countries, with mid-trophic level and demersal species most severely affected, and small-scale fleets showing greater vulnerability than their industrial counterparts. This dissertation advances our understanding of the socioeconomic consequences of ocean deoxygenation and highlights the importance of interdisciplinary approaches in developing effective management strategies to address this growing global challenge. The findings support the need for precautionary fisheries management that maintains healthy biomass levels while reducing fishing pressure on vulnerable species.
Examining Committee
Rashid Sumaila (Supervisor, Institute for the Oceans and Fisheries/School of Public Policy and Global Affairs, UBC);
Debby Ianson (Committee member, Ocean Sciences, DFO/Earth and Ocean Sciences, UVic);
William Cheung (University examiner, Institute for the Oceans and Fisheries, UBC);
Harry Nelson (University examiner, Department of Forest Resources Management, UBC);
Karin Limberg (External examiner, Department of Environmental Biology, SUNY);
Carol McAusland (Exam chair, Food and Resource Economics, UBC).