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UBC Theses and Dissertations

Estimating aerobic and anaerobic capacities using the respiratory assessment paradigm : a validation using Atlantic salmon (Salmo salar) and European sea bass (Dicentrarchus Labrax) Zhang, Yangfan


Assessing fish performance, whether for extrapolation to natural conditions, culture conditions or toxicology, has a long history of using swim performance, metabolic rates and performance in hypoxia. However, rarely are these metrics unified in a test. Hence, thesis’ objective was to test a respiratory assessment paradigm (RAP), which comprehensively evaluated aerobic and anaerobic metabolism by explicitly measuring aerobic capacity, recovery and performance in hypoxia. To provide high fish throughput with each test, RAP used multiple intermittent-flow respirometry systems. I tested RAP by examining two practical questions: do aquaculture practices compromise the respiratory robustness of domesticated Atlantic salmon (Salmo salar) and, if so, how might it be reversed? Second, does an acute sub-lethal exposure to chemically dispersed oil have a chronic residual respiratory effect on European sea bass (Dicentrarchus labrax). RAP revealed a domesticated (Bolaks) strain of Atlantic salmon had a lower aerobic capacity than a wild (Lærdal) strain. Incremental exercise training significantly increased aerobic and recovery capacities in only the Lærdal strain. Thus, the Bolaks strain appeared to be athletically less robust than Lærdal strain. As a conclusion, ten generations of growth-oriented breeding program of Bolaks strain in commercial aquaculture have reduced its athletic robustness and cardiorespiratory plasticity as compared to their wild conspecifics. Given the success in improving athletic robustness of the wild strain, it still remains to explore whether an exercise- training protocol can be developed that will provide benefits to the salmon aquaculture industry. RAP discovered no residual effect of oil on aerobic capacity for either hypoxia tolerant (HT) or hypoxia sensitive (HS) sea bass. Instead, RAP discovered a residual effect for only the HT phenotype on its ability to survive in hypoxia, which was evidenced by an impaired tolerance to hypoxia and an increased oxygen deficit in hypoxia. Therefore, RAP identified a chronic impairment from acute exposure to oil to the hypoxia-tolerant segment of the sea bass population, perhaps increasing their risk of perishing in hypoxic episodes. These successful applications illustrate that RAP is a reliable methodology that could find further application to comparative studies of thermal, hypoxic and anthropogenic effects on the ecological performances of fishes.

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