The Effects of Hydraulic Fracturing Flowback and Produced Water on Exercise Capacity and Metabolic Fuel Selection in Rainbow Trout (Oncorhynchus mykiss)
Creators: Cyr, Anika
Publisher: name: University of Alberta Library
Year: 2022

<p>Hydraulic fracturing is an increasingly popular technique for unconventional hydrocarbon extraction in Canada. As its popularity continues to grow, concerns are being raised regarding its waste product, hydraulic fracturing flowback and produced water (FPW), and its effects on the environment. Over the last decade, several thousand incidents of FPW spills have been recorded in Canada. Many of these releases will eventually make their way into waterways which impact aquatic biota. <br>
This study is the first to investigate the effects of hydraulic fracturing FPW on energetics and swim performance in adult rainbow trout in vivo. Using double aortic cannulation in trout exposed to either control (no exposure), diluted FPW, or a salinity-matched solution (SW), swim performance, metabolic fluxes, fuel utilization, and enzyme activity, were assessed. <br>
Swim performance was not significantly impacted by the exposure of fish to either SW (6.64%) or FPW (6.64%). Metabolic fluxes (glycerol and carbohydrate) were also unaffected by SW and FPW. Plasma metabolites presented some noticeable and significant changes as a result of exercise and/or treatment. Both SW-treated and FPW-treated fish had noticeably lower plasma glycerol concentrations, whereas plasma glucose concentration was generally higher but more variable than control. SW-treated fish were the only group showing significant increases in plasma lactate during exhaustive exercise. <br>
Measurement of metabolic enzyme activity produced mixed results. The carbohydrate-related metabolism enzymes, pyruvate kinase, and lactate dehydrogenase were not altered from exposure to either SW or FPW relative to control, whereas lipase enzyme activity was noticeably increased in SW-treated and FPW-treated fish relative to controls. <br>
Oxidative stress biomarkers were also measured, and both SW and FPW exposure induced noticeable and significant alterations in activity. In FPW-treated fish, liver EROD activity significantly increased whereas the same enzyme in gill tissue was noticeably impaired. TBARS showed an inverse response in liver and gill EROD results. <br>
Although there were alterations in some energetic parameters within this study, they were not consistent with the original hypothesis that FPW would impair metabolic fluxes and subsequently alter energetics and swim performance.  I interpret these results as either the SW and FPW exposures induced an effect on key parameters measured within the study through direct alterations without altering metabolic fluxes or that FPW and SW induced an indirect metabolic and energetic response via stress axes and compensatory mechanisms. <br>
This thesis is the first to examine the effects of complex hydrocarbon-based pollutants (FPW) exposure on adult rainbow trout metabolic substrate physiology, their energetics, and swim performance responses in vivo. Through the culmination of assessing these hazard effects of FPW can we improve risk management and help protect values ecosystems within Canada.</p>