You are encouraged to attend the defence. The details of the defence and attendance information is included below:  

Date: July 10, 2025  
Time: 1:00 PM to 3:00 PM (PT)

Defence mode: Hybrid
In-Person Attendance: Small Lecture Theatre Agora (7-150), UNBC Prince George Campus  
Virtual Attendance: via Zoom

LINK TO JOIN: Please contact the Office of Graduate Administration for information regarding remote attendance for online defences.  

To ensure the defence proceeds with no interruptions, please mute your audio and video on entry and do not inadvertently share your screen. The meeting will be locked to entry 5 minutes after it begins: please ensure you are on time.  

Thesis entitled: GAAT (SOCKEYE SALMON, ONCORHYNCHUS NERKA) MIGRATION UP THE GAAT HÉENI (SILVER SALMON RIVER): INFLUENCE OF ATMOSPHERIC RIVERS ON HYDROLOGIC VARIABILITY   

 Abstract: Atmospheric rivers (ARs) drive hydrometeorological variability, influencing precipitation, river discharge and water temperature. This study quantifies how ARs contribute to precipitation and hydrology in the Gaat Héeni (Silver Salmon River) Watershed, a key migration corridor for Sockeye Salmon. I integrate ERA5-Land reanalysis and the SIO-R1 atmospheric river catalog with in situ hydrometric measurements and biological monitoring data, including video observations at a waterfall barrier and escapement counts from a weir. This approach allows me to evaluate how AR-driven changes in hydrologic conditions subsequently influence Sockeye Salmon migration success.

Sockeye Salmon jump success, modelled using logistic regression, was primarily influenced by river discharge, with peak success occurring at 10–12 m³ s⁻¹ discharge levels. Jump success at SR3-3 declined at discharge levels above 16 m³ s⁻¹ or below 9 m³ s⁻¹. Although water temperatures of 13–15 °C coincided with optimal jump success, water temperature was not a statistically significant predictor, reducing confidence in its influence relative to discharge.

Results show that AR events contributed between 15.9% and 39.1% of seasonal precipitation from 1991 to 2023, with the highest contributions in fall (37.9%) and winter (24.1%). During the 2024 monitoring season, an AR event on 22–24 July triggered a discharge surge from 8.7 to 30.0 m³ s⁻¹ within two days, reflecting the watershed’s rapid hydrologic response. Centroid lag analysis revealed a median discharge lag of 1.6 days following AR-driven precipitation, underscoring the sensitivity of discharge timing to ARs.

Defence Committee:  
Chair: Dr. Pranesh Kumar, University of Northern British Columbia  
Supervisor: Dr. Stephen Dery, University of Northern British Columbia  
Committee Member: Dr. Peter Jackson, University of Northern British Columbia  
Committee Member: Dr. Jonathan Moore, Simon Fraser University
External Examiner: Dr. Eran Hood, University of Alaska Southeast