Bibliography: leaves 190-212. / xxiii, 240 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / This thesis describes a thrust vectoring nozzle (TVN) which produces a jet which may be deflected at angles in excess of 80o from the nozzle axis by fluid dynamic means, while maintaining total thrust efficiency of the order of 50%, or at 50o with an efficiency of the order of 70%. The thrust vectoring by fluid dynamic means is achieved by injecting secondary fluid at the nozzle throat and partially separating the primary jet causing it to deform. / Thesis (Ph.D.)--University of Adelaide, Dept. of Mechanical Engineering, 1995

Herbivorous reef fish are a key functional group for the ecological resilience of coral reefs. Asthey feed on algae, a major resource competitor of coral polyps, they can prevent and reversecoral-macroalgal phase shifts. The resilience of the reefs against such phase shifts is given bythe ability of herbivores to keep the system in a cropped state from filamentous algae or bytheir capacity to feed on macroalgae. Most of the management plans that aim to protect coralreefs have been focusing on the establishment of marine protected areas or no-take areas wherefishing activities are strictly restricted or prohibited. In low-income countries, such managedareas can be difficult to accept from a fisher´s perspective and lack of money also tends to leadto limited surveillance capabilities and lowered compliance. These challenges are important toaddress when managing small-scale fisheries and where fish are considered as both, amarketable commodity and a subsistence good.A perhaps less contentious strategy for fishers is gear-based management, where the use offishing gears that are detrimental to coral reef resilience are restricted and at the same timegears that do not compromise resilience are promoted. This study aims to investigate how ninedifferent fishing gears (i.e. different lines, traps, nets and spears) used in the coral reef fisheriesof Zanzibar (Tanzania) capture herbivorous reef fish that can prevent (preventers) or reverse(reversers) coral-macroalgal phase shifts. Two interesting findings emerged from the study.First, different fishing gears had different impacts on these two functional groups where lines,large traps and seine nets fisheries had most impacts. Second, there were monsoonaldifferences in the catch of preventers and reversers. These findings are discussed in relation toi) similar studies conducted in different reef environments and ii) the feasibility of gear-basedmanagement in Zanzibar.