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Effective management of freshwater fish habitat is essential to supporting healthy aquatic ecosystems and sustainable fisheries. In Canada, recent changes to the Fisheries Act enhanced the protection of fish habitat, but application of those provisions relies on sound scientific evidence. We employed collaborative research prioritization methods to identify scientific research questions that, if addressed, would significantly advance the management of freshwater fish habitat in Canada. This list was generated by a diverse group of freshwater fish experts, including substantial contributions from practitioners who administer provisions of the Fisheries Act. The research questions generated in this study identify priority topics for future research, while highlighting issues that could be addressed with different funding models. As a result, this study should support evidence-based management of Canada’s aquatic resources by identifying scientific knowledge gaps faced by practitioners, and suggesting mechanisms to address them. Given the important contribution of Canadian freshwater systems to global ecosystem values, and the similar scientific challenges facing fish habitat managers in other jurisdictions, this study is likely to have broad applicability.

The bacterium Clostridium perfringens causes a wide range of diseases in animals and humans. These diseases are typically caused by the production of bacterial toxins. The genetic factors within C. perfringens that carry these toxins are called plasmids. In this thesis, a new family of plasmids that is important for the spread of toxin genes throughout a bacterial population was identified and characterised. In addition, the mechanism by which C. perfringens maintains more than one of these toxin plasmids was determined. This study provides insight into the fundamental processes that allow C. perfringens to be such a successful disease producing bacterium.

Mechanical designs in industry typically do not include adequate specification of allowable part geometry variation. Poorly applied Geometric Dimensioning and Tolerancing (GD&T), ambiguous plus/minus location or orientation controls, and sometimes no variation specifications (only a 3D CAD body) are commonly all that is done. Since improper specifications cause confusion, and since functional requirements are likely either more precise, or less precise, than the manufacturing process will deliver, excessive costs of dealing with geometry variation result. Specifications which unambiguously capture the functional needs of critical part features, combined with properly gathered and consistently reported measurement data would provide a competitive advantage for any company producing a precise mechanical product. The need to capture functional requirements, and also the improved part designs that result when thinking includes the cost & quality issues clarified by GD&T makes this subject an important element of design focused mechanical engineering education. Especially when tolerance analysis and measurement process quality considerations are included, there is sufficient academic rigor to justify additional coursework. The critical seed needed to remedy industry’s knowledge gap regarding dimensional specifications and associated data is to include two academic quarters of GD&T and Dimensional Management design electives as part of every mechanical engineering curriculum.