The University of British Columbia
Our Research
Coho salmon (Oncorhynchus kisutch) and chum salmon (Oncorhynchus keta) spawn in streams which traverse highly urbanized areas of the Vancouver Lower Mainland. Contaminants in road runoff pose a threat to the health of freshwater streams, which are home to juvenile salmon and important spawning habitat for returning adults. At UBC, students and professors are analyzing the data from our network of conductivity loggers and are investigating the impact of road salt on the development of early life stages of salmonids. We have found that in some streams, salt concentrations in winter pulses may exceed the BC acute water quality guideline for chloride (600 mg/L), by more than 10-fold. In pilot experiments with rainbow trout (Oncorhynchus mykiss) we have found that these pulses cause significant mortality and developmental abnormalities. We are now investigating how such pulses in salinity are impacting the survival, development, and physiology of coho and chum salmon at early life stages.
MAIN FINDINGS
During spawning, as well as embryonic and larval development, Pacific salmon are frequently exposed to pulses of road salt. Laboratory-based experiments are being conducted to investigate the effects of road salt contamination on these critical early life stages, focusing on various concentrations and exposure frequencies.
(Carley Winter, UBC)
How much salt, is too
much salt?
Coho salmon eggs were fertilized and then immediately exposed to one 24H road salt pulse at one of five environmentally relevant salt concentrations, ranging from 0 to 4,800 mg/L of chloride. After 24H, embryo continued to develop in freshwater until hatch.
Significant mortality was observed when chloride concentrations reached >1,800 mg/L. (3x the provincial guideline for chloride)
(Carley Winter, UBC)
Accumulated Thermal Units (ATU) is the cumulation of daily temperature used to identify salmonid life stages.
Fish develop faster at warmer temperatures!
Do repeated salt pulses increase mortality?
Freshly fertilized coho eggs were exposed to road salt pulse regimes meant to mimic what they might realistically experience in a Vancouver stream. Eggs were exposed to either 1, 2 or 3 salt pulses, spaced 48 hours apart, at 2,400 mg/L chloride (4x the province’s acute guideline).
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There was an increase in mortality with an increase in pulse frequency!
(Clare Kilgour, UBC)
Recent Publications
Kilgour, C.L., Winter, C.E., Brauner, C.J., Chara‑Serna, A.C., James, A.C., Kroetsch, N.C., Schulte, P.M., & Wood, C.M. (2025). Tracking road salt contamination through community monitoring: Annual surface water chloride trends in streams of a major urban area, the Vancouver Lower Mainland, B.C., Canada. Archives of Environmental Contamination and Toxicology. doi: 10.1007/s00244-025-01156-3
Winter, C.E., Kilgour, C.L., Brauner, C.J., Schulte, P.M., & Wood, C.M. (2026). Effects of pulse exposures to road salt at various stages of early development in rainbow trout (Oncorhynchus mykiss). Comparative Biology and Biochemistry C. https://doi.org/10.1016/j.cbpc.2025.110334
Winter, C.E., Kilgour, C.L., Brauner, C.J., Schulte, P.M., & Wood, C.M. (2026). Road Salt Creates a Slippery Slope for Pacific Salmon: Environmentally Realistic Salt Pulses Have Lethal and Sublethal Effects on Developing Coho Salmon (Oncorhynchus kisutch). Aquatic toxicology. https://doi.org/10.1016/j.aquatox.2026.107737
RESEARCH TEAM
Dr. Patricia Schulte
Professor in Department of Zoology, UBC
The Schulte lab uses approaches including physiology, genomics, and population genetics to understand the physiological adaptations that allow animals to live in particular environments
Dr. Chris Wood
Adjunct Professor in Department of Zoology, UBC
The Wood lab focuses on animal physiology and toxicology, investigating the sublethal effects of natural factors (temperature, oxygen, water chemistry, exercise, feeding, social interactions) and anthropogenic pollutants (metals, ammonia, low and high pH, climate change, salinization) on organismal function, and the strategies by which animals adapt to extreme environments.
Dr. Colin Brauner
Professor in Department of Zoology, UBC
The Brauner lab investigates environmental adaptations (both mechanistic and evolutionary) in relation to gas-exchange, acid-base balance and ion regulation in fish, integrating responses from the molecular, cellular and organismal level.
Carley Winter
Research Technician
MSc Graduate. Department of Zoology, UBC
"My interests led me to an environmental research and toxicology lab where I performed standardized and specialized tests
working with various vertebrates and invertebrates.
On the Road Salt Project I am investigating the effects of environmentally relevant salt concentrations, determining which concentrations have the greatest developmental impact on rainbow trout and coho and chum salmon. "
Clare Kilgour
PhD Candidate. Department of Zoology, UBC
"My technical background is in
freshwater ecology and developmental biology, so I equally love getting muddy in the field and spending time behind a microscope. As part of the Road Salt Project, I'll be simulating multiple pulses of salinity, to determine the impact pulses of road salt has on the development and success of juvenile Coho and Chum salmon"
Jack Hall
MSc Student. Department of Zoology, UBC
"Coming from the world of habitat restoration, I have a keen interest in how organisms are affected by changes humans make to their environment. My part of the Road Salt Project will be to study the effects of repeated salinity pulses across the entire developmental timeline of Chum salmon, and investigate what effects this might have on their growth, survival, and genetic expression."