Open Collections

Sajanthan, Linoja

University of British Columbia

Salmon aquaculture has expanded significantly along the coast of British Columbia over the past several decades, contributing to food security and rural economies. However, this growth has coincided with widespread declines in wild Pacific salmon populations. A growing body of research points to disease transmission and ecological stressors from open-net pen farms particularly those situated along key migration corridors and near spawning habitats as contributing factors. While biological and experimental studies have highlighted these risks, they often focus on specific species or localized areas, limiting generalization. This thesis estimates the causal impact of salmon farms on wild Pacific salmon across British Columbia. Using stream-level salmon escapement data and geospatial records of aquaculture operations, we construct a spatial exposure framework linking salmon farms to river mouths of salmon spawning streams. Employing two-way fixed effects models controlling for stream, species, and year, we find that each additional salmon farm within 10 km of stream mouths significantly reduces wild salmon returns by approximately 638 fish (p < 0.05). These negative effects are consistent across species, with particularly strong impacts observed for Pink and Chinook salmon. This research provides the first province-wide, stream-level econometric analysis of aquaculture impacts on wild Pacific salmon returns. The results underscore the ecological risks posed by spatial overlap between aquaculture infrastructure and salmon migration corridors, and support the development of spatially informed regulatory policies aimed at safeguarding wild salmon populations in British Columbia.

Text

2025-06-23

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/91411

Integrated Studies in Land and Food Systems

University of British Columbia

UBCV

http://creativecommons.org/licenses/by-nc-nd/4.0/