Grant: Discovery Grants Program - Individual

Climate change has created an urgency to determine species vulnerability to increasing temperatures. Pacific salmon are especially vulnerable given their narrow optimal temperature range, exposure to high freshwater temperatures during juvenile rearing & adult migrations, and a limited capacity to extend upper thermal tolerance. Natal homing and natural selection have led to fine-tuned local adaptations including a population's ability to cope with high temperatures. Upper thermal tolerance is believed to be correlated with historic freshwater thermal experiences suggesting that Pacific salmon populations possess some adaptive potential to warming. However, many populations are already imperiled and potential for these to adapt thermal tolerance to match the pace at which water temperatures are rising remains unknown. The evolutionary race between climate change and salmon thermal vulnerability is well underway. British Columbia Pacific salmon are in a conservation crisis and increasing freshwater temperatures are likely a key factor in the decline. There is recent evidence that Pacific salmon have both physiological and genetic capacities to increase thermal tolerance through heritable changes to thermal performance of their hearts. While our current understanding of large-scale migration behavioural physiology in adult Pacific salmon is one of the most comprehensive of any animal system, the role of thermal tolerance on fitness, the ability to spawn and create abundant healthy offspring, is an important knowledge gap which my proposed research will help address. We will use field-based respirometry and spawning experiments involving several populations of salmon, along with cutting-edge genomic approaches to examine eco-physiological mechanisms of thermal limits in a salmon species across a large spatial scale and provide insight as to why some populations are currently collapsing. We will use results to build a map-based `vulnerability tool', which can be used by the public and decision-makers to visualize locations where populations are at risk of imminent extirpation given climate change projections, so that informed decisions can be made for spatially restricting fisheries and enhancing protection of regional thermal habitats. As one of the few labs in Canada focusing on the eco-physiology, genomics and fitness of salmon migrations, we are training the next generation of students with field, lab, quantitative, communication and decision-making skills necessary to obtain careers in fisheries science, management and policy, and we include considerations for diversity and inclusivity as core elements in our training environment. Our novel science, diverse collaborators and partners, and massive extension efforts, ensures that research results get incorporated into management and policy which is critical given the rapid pace of climate change and its consequences to salmon population sustainability.